This PDF file contains the front matter associated with SPIE Proceedings Volume 13092, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

NASA’s Astrophysics Division features annual solicitations to fund technology development for future space flight missions. Two major, repeated calls for proposals are the Astrophysics Research and Analysis (APRA) and the Strategic Astrophysics Technology (SAT) opportunities, and there are occasional solicitations for other technology development programs. We will present the paradigm used in these solicitations, including the process for how technologies have been prioritized for inclusion in the SAT opportunity. We have statistics on selections, including groupings by subject matter and how these have evolved over time. We will discuss anecdotal aspects of NASA’s technology innovation, maturation, and flight pipeline, and how it supports early-career researchers.

The Pandora SmallSat mission is a NASA Astrophysics Pioneers mission whose goal is to assess the impact of stellar activity on exoplanet transmission spectroscopy. A secondary goal of both the Pioneers program and the Pandora mission is to provide space mission experience to early career participants with a range of expertise including scientists, engineers, and project managers. Pandora is facilitating the involvement of early career participants from undergrad to post-grad through a variety of formal and informal programs including summer internships, year long graduate student shadow opportunities, post-doctoral programs, and formal mission roles. The success of early career participants within the mission is enabled by pairing them with mentors as well as the identification and assignment of responsibilities that match their capabilities with mission needs. In addition, the Pandora mission leadership team developed and established rules of conduct to set clear expectations for all mission participants. We will discuss the details of these programs, lessons learned, and summarize the best practices Pandora has developed which enable us to contribute to the pipeline of scientists and technologists with space mission experience (while simultaneously developing a SmallSat mission).

This paper describes the development of a new system from the vantage point of our previous experience on Chandra and James Webb. We introduce and define what we call the problem of newness, namely system development with an incomplete understanding of the system performance. We will discuss programmatic and technical approaches to maximize engineering productivity in the development of a new complex system like NASA’s Habitable Worlds Observer or other future flagship missions.

The rise of time-domain astronomy including electromagnetic counterparts to gravitational waves, gravitational microlensing, explosive phenomena, and even astrometry with Gaia, are showing the power and need for surveys with high-cadence, large area, and long time baselines to study the transient universe. A constellation of SmallSats or CubeSats providing wide, instantaneous sky coverage down to 21 Vega mag at optical wavelengths would be ideal for addressing this need. We are assembling CuRIOS-ED (CubeSats for Rapid Infrared and Optical Survey–Exploration Demo), an optical telescope payload which will act as a technology demonstrator for a larger constellation of several hundred 16U CubeSats known as CuRIOS. The full CuRIOS constellation will study the death and afterlife of stars by providing all-sky, all-the-time observations to a depth of 21 Vega magnitudes in the optical bandpass. In preparation for CuRIOS, CuRIOS-ED will launch in late 2025 as part of the 12U Starspec InspireSat MVP payload funded through the Canadian Space Agency. CuRIOS-ED will be used to demonstrate the <1” pointing capabilities of the StarSpec ADCS system and to space-qualify a commercial camera package for use on the full CuRIOS payload. The CuRIOS-ED camera system will utilize a Sony IMX455 CMOS detector delivered in an off-the-shelf Atik apx60 package which has no previous space heritage. We deconstructed and repackaged the apx60 camera to make it compatible with operations in vacuum environments as well as the CubeSat form factor, power, and thermal constraints. By qualifying this commercial camera solution, the cost of each CuRIOS satellite will be greatly decreased (∼ 100×) when compared with current space-qualified cameras with IMX455 detectors. Therefore, the results from this work have great implications on the CuRIOS mission as well as other Cube or SmallSat missions. We discuss the CuRIOS-ED mission design with an emphasis on the disassembly, repackaging, and testing of the Atik apx60 for space-based missions. The testing results include characterization of the Sony IMX455 detector and Atik electronics performance. We find a read noise of 2.43±0.05 e- at a gain of 1 electron/ADU and detector temperatures ranging from -10 C to 25 C. The apx60’s dark current is well below an electron per second at the temperatures and exposure times tested. The apx60 camera also exhibits patterned noise in the form of horizontal striping and an asymmetric signal gradient which increases across the detector’s columns. We will also comment on preliminary environmental testing results.

CubeSpec is an in-orbit demonstration CubeSat mission in the ESA GSTP programme, developed and funded by the Belgian federal space policy BELSPO. The goal of the mission is to demonstrate high-spectral-resolution astronomical spectroscopy from a 12-unit CubeSat. The technological challenges are numerous. The optical payload, consisting of an off-axis Cassegrain telescope and a compact Echelle spectrometer have been designed to fit in the bigger half of a 12U CubeSat (12x20x30cm). The telescope is built entirely from a ceramic material to limit defocusing when the spacecraft thermal environment changes. The payload radiator is shielded from the Sun via a deploying Sun shade, allowing pointing to a large part of the sky without illuminating the radiator panel. The high resolution spectrograph requires arcsecond-level pointing stability. This is achieved using a performant 3-axis wheel stabilised attitude control system with two star trackers augmented with a piezo-actuated 3-axis fine beam steering mechanism in the payload. CubeSpec is now starting the implementation phase, with a planned launch in 2026. A qualification and a flight model are being constructed and tested. We give an overview of the mission, its technologies and qualification status.

The CANDLE Engineering Demonstration Unit (EDU) was selected by the 2022 APRA program to develop and demonstrate the ability to reach the flux accuracy and range required for an artificial flux calibration star. A critical issue in producing accurate and reliable flux calibration is systematic effects; this EDU is providing a path to deploying an artificial star calibration payload outside Earth’s atmosphere with SI-traceable calibration that enables accurate throughput characterization of astronomical and earth science observatories in space and on the ground. Such a payload could be carried independently on a dedicated platform such as an orbiting satellite, e.g. the Orbiting Configurable Artificial Star (ORCAS), by a star shade at L2, or some other independent platform to enable accurate end-to-end throughput vs. wavelength calibration that can be measured repeatedly throughout the operational lifetime of an observatory. Once calibrated, the observatory is enabled to carry out astrophysical programs whose science objectives demand high accuracy and/or high precision observations. One specific and immediate application is establishing SI-traceable standard stars beyond the current limited set. We show in this paper the progress made in developing this EDU.

The Line Imaging Orbiter for Nanosatellite-Enabled Spectrographic Surveys (LIONESS) is a 6U cube satellite mission in development at Columbia University, supported for a 2027 launch by the NASA CubeSat Launch Initiative. The student-driven CubeSat will host a narrowband integral field spectrograph with a microlens field slicer, drawing inspiration from, and intending to complement Columbia’s ground-based Circumgalactic Hα Spectrograph (CHαS) deployed at MDM Observatory. The circumgalactic medium (CGM) may account for up to 90% of a galaxy’s mass, yet its properties are not well understood. LIONESS will observe the diffuse CGM in low-redshift galaxies, imaging hydrogen spectra to extract information about gas distribution, mass, composition, and kinematics, and aiming to provide insights into galactic formation and gas flow between the CGM and disk. As a space-based companion to CHαS, LIONESS will offer comparable narrowband H-alpha imaging over a one-degree field of view, with a significantly lower background. We present results from an initial mission concept study, flight hardware plans, and the development of an at-scale optomechanical prototype of the LIONESS spectrograph.

To investigate the evolution of our Galaxy, we plan to measure the distances and motions of stars in the Galactic center region. Additionally, our goal is to detect planets within the habitable zone around mid-M-type stars using transit phenomena. To achieve these objectives, we initiated the Japan Astrometry Satellite Mission for Infrared Exploration (JASMINE) project, targeting a 40 microarcsecond annual parallax measurement and aiming photometric accuracy of less than 0.3% for mid-M-type stars. A conceptual study of the observation instrument was conducted. As a result, the telescope is designed with high stability in orbit through carefully chosen materials and a special thermal design. A three-year operation is planned to collect sufficient data for annual parallax measurements. The telescope, with a diameter of 36 cm, covers wavelengths from 1.0 to 1.6 microns using InGaAs detectors. This paper will detail how instrument parameters were selected based on scientific objectives.

With sub-microarcsecond angular accuracy, the Theia telescope will be capable of revealing the architectures of nearby exoplanetary systems down to the mass of Earth. This research addresses the challenges inherent in space astrometry missions, focusing on focal plane calibration and telescope optical distortion. We propose to assess the future feasibility of large-format detectors (50 to 200 megapixels) in a controlled laboratory environment. The aim is to improve the architecture of the focal plane while ensuring that specifications are met. The use of field stars as metrological sources for calibrating the optical distortion of the field may help to constrain telescope stability. The paper concludes with an attempt to confirm in the laboratory the performance predicted by simulations. We will also address the possibility of using such techniques with a dedicated instrument for the Habitable World Observatory.

The TOLIMAN mission will fly a low-cost space telescope designed and led from the University of Sydney. Its primary science targets an audacious outcome in planetary astrophysics: an exhaustive search for temperateorbit rocky planets around either star in the Alpha Centauri AB binary, our nearest neighbour star system. By performing narrow-angle astrometric monitoring of the binary at extreme precision, any exoplanets betray their presence by gravitationally, engraving a tell-tale perturbation on the orbit. Recovery of this challenging signal, only of order micro-arcseconds of deflection, is normally thought to require a large (meter-class) instrument. By implementing significant innovations optical and signal encoding architecture, the TOLIMAN space telescope aims to recover such signals with a telescope aperture of only a 12.5cm. Here we describe the key features of the mission: its optics, signal encoding and the 16U CubeSat spacecraft bus in which the science payload is housed - all of which are now under construction. With science operations forecast on a timescale of a year, TOLIMAN aims to determine if the Sun’s nearest neighbour hosts a potential planetary stepping stone into the galaxy. Success would lay down a visionary challenge for futuristic high speed probe technologies capable of traversing the interstellar voids.

On 29th September 2022, the airborne observatory SOFIA flew its final science flight, concluding nearly 12 years of successful science operations. While the Astro2020 review has enabled the possibility of a NASA far-IR probe mission, such a platform - if realized instead of the alternative X-ray option - would likely not observe at best until the early-2030s. Therefore, for at least the next decade, the wavelength regime between ~30-300 µm has become inaccessible to the international community, aside from an assortment of upcoming and planned balloon-borne missions. This regime encompasses a range of key astrophysical observables across multiple spatial scales - from local star-forming cores, to molecular cloud complexes, to entire galaxies. As demonstrated by SOFIA observations, these include tracers of star formation & feedback, strong gas cooling lines, and diagnostics of dense ISM morphology, dynamics & polarization. The launch of JWST has opened new possibilities in the near- and mid-IR universe; however, the lack of complementary access to the far-IR will hamper our understanding of key concepts. In this paper, we will overview some of SOFIA’s science highlights, and present a number of major science cases for continuing far-IR observations. We will outline ongoing efforts to reprocess and preserve SOFIA’s scientific and technical archive. Finally, we will discuss how SOFIA’s scientific legacy was enabled by particular instrumentation & platform capabilities, establish where and how these capabilities can be improved upon, and place these in the context of future airborne and spaceborne far-IR mission proposals and concepts.

Single Aperture Large Telescope for Universe Studies (SALTUS) is a proposed NASA Probe class mission that will provide a powerful far-infrared (far-IR) pointed space observatory to explore our cosmic origins and the possibility of life elsewhere. During its 5 year baseline mission, SALTUS will perform groundbreaking studies towards 1000s of astrophysical targets, including the first galaxies, protoplanetary disks, and numerous solar system objects. SALTUS employs a deployable 14-m aperture, with a sunshield that will radiatively cool the off-axis primary to <45K, along with cryogenic coherent and incoherent detectors that span the 34 to 660 𝜇m far-IR range at both high and moderate spectral resolutions. This spectral range is unavailable to any existing ground or space observatory. SALTUS will have 16x the collecting area and 4x the angular resolution of Herschel and is de-signed for a lifetime ≥5 years. With its large aperture and powerful suite of instruments, SALTUS’s observations will provide a giant leap forward in our capabilities to study the local and distant universe.

The SAFARI-lite instrument on the SALTUS mission with its large 14 meter diameter aperture, will present the astronomical community with an unprecedented observational capability providing extremely sensitive FarIR spectroscopy at high spatial resolution. With the combination of SALTUS’ large collecting area and an array of sensitive Kinetic Inductance Detectors (KIDs) in a compact grating spectrometer configuration the SAFARI-lite instrument will generate R~300 resolution 34-230 μm spectra reaching sensitivities of order 10-20 W/m2 (5σ/1 hour) – an observing capabilityy in the Far Infra-Red domain with both spatial resolution and sensitivity at levels comparable to JWST. The instrument will provide both point source optimized spectroscopy observing modes, as well as spectroscopic imaging for small fields. With this breakthrough capability astronomers will be able to fully address many fundamental astrophysical issues like understanding the evolution of galaxies over cosmic time, following the distribution and role of water in the evolution those galaxies, and unveiling the formation history of planetary systems in general and our own solar system in particular.

FIRSST is a far-infrared pointed space-borne observatory led at APL for the 2023 Astrophysics $1B Probe Class mission competition. FIRSST payload consists of a 1.8m telescope that is cryo-cooled to a temperature of 4.7K and two instruments that allow sensitive far-infrared spectroscopy between 35 to 600 microns with resolving powers up to a million. The PI-led science program of FIRSST aims to understand how galaxies grow in the universe, why super-Earths to mini-Neptunes are the most frequent planets, and what is the source of water in rocky planets. As required by NASA, 75% of the mission five-year lifetime is left open to be used by the astronomical community through a time allocation process, similar to the selection of science programs with Hubble and JWST. This talk will summarize the history of far-infrared astronomy, science objectives and requirements, and the technical details of FIRSST.

The Direct Detection Spectrometer Instrument (DDSI) is one of two instruments designed for the Far-IR Spectroscopy Space Telescope (FIRSST) recently proposed to NASA in response to the Astrophysics Probe Explorer call. The DDSI consists of two modules: HR delivering spectra at R~20,000 to 100,000 in three select bands (HR1-3) across 56-184μm, and LR providing broadband spectral coverage at R~100 in four bands (LR1-4) across 35-260 µm. The dispersive element of the HR bands is a compact optical resonator known as a virtually imaged phase array. All DDSI bands use microwave kinetic inductance detector (MKID) arrays cooled to 120mK. The total DDSI MKID pixel count is 2612 pixels.

The Heterodyne Spectrometer Instrument (HSI) is one of two instruments designed for the Far-IR Spectroscopy Space Telescope (FIRSST) recently proposed to NASA in response to the Astrophysics Probe Explorer call. HSI will be the first THz cryogenic heterodyne array receiver implemented for a space mission. It has extremely high spectral resolving power (R>10^6) in order to allow detailed spectral observations. HSI covers a very wide bandwidth range between 150 and 600 microns in only 3 bands, each equipped with two 5-pixel arrays. HSI enables highly sensitive dual-polarization, multi-pixel and multi-frequency observations on a space telescope, by a careful design and by employing low-heat dissipating, low-power, but high TRL components.

PRIMA addresses questions about the origins and growth of planets, supermassive black holes, stars, and dust. Much of the radiant energy from these formation processes is obscured and only emerges in the far infrared (IR) where PRIMA observes (24–261 um). PRIMA’s PI science program (25% of its 5-year mission) focuses on three questions and feeds a rich archival Guest Investigator program: How do exoplanets form and what are the origins of their atmospheres? How do galaxies’ black holes and stellar masses co-evolve over cosmic time? How do interstellar dust and metals build up in galaxies over time? PRIMA provides access to atomic (C, N, O, Ne) and molecular lines (HD, H2O, OH), redshifted PAH emission bands, and far-IR dust emission. PRIMA’s 1.8-m, 4.5-K telescope serves two instruments using sensitive KIDs: the Far-InfraRed Enhanced Survey Spectrometer (continuous, high-resolution spectral coverage with over an order of magnitude improvement in spectral line sensitivity and 3-5 orders of magnitude improvement in spectral survey speed) and the PRIMA Imager (hyperspectral imaging, broadband polarimetry). PRIMA opens new discovery space with 75% of the time for General Observers.

The PRobe far-Infrared Mission for Astrophysics (PRIMA) is an actively cooled, infrared observatory for the community for the next decade. On board, an infrared camera, PRIMAger, will provide observers with coverage of mid-infrared to far-infrared wavelengths from about 25 to 264 microns. PRIMAger will offer two imaging modes: the Hyperspectral mode will cover the 25-80 microns wavelength range with a resolution R~10 while the Polarimetric mode will have four broad-band filters, sensitive to polarization, from 80 to 264 microns. These capabilities have been specifically tailored to answer fundamental astrophysical questions such as black hole and star-formation coevolution in galaxies, the evolution of small dust grains over a wide range of redshifts, and the effects of interstellar magnetic fields in various environments, as well as opening a vast discovery space with versatile photometric and polarimetric capabilities.

FIRESS is the multi-purpose spectrometer proposed for the PRobe far-Infrared Mission for Astrophysics (PRIMA). The sensitive spectrometer on the cold telescope provide factors of 1,000 to 100,000 improvement in spatial-spectral mapping speed relative to Herschel, accessing galaxies across the arc of cosmic history via their dust-immune far-infrared spectral diagnostics. FIRESS covers the 24 to 235 micron range with four slit-fed grating spectrometer modules providing resolving power between 85 and 130. The four slits overlap in pairs so that a complete spectrum of any object of interest is obtained in 2 pointings. For higher-resolving-power studies, a Fourier-transform module (FTM) is inserted into the light path in advance of the grating backends. The FTM serves all four bands and boosts the resolving power up to 4,400 at 112 microns, allowing extraction of the faint HD transition in protoplanetary disks. FIRESS uses four 2016-pixel arrays of kinetic inductance detectors (KIDs) which operate at the astrophysical photon background limit. KID sensitivities for FIRESS have been demonstrated, and environmental qualification of prototype arrays is underway.

During its 6-year nominal mission, Euclid shall survey one third of the sky, enabling us to examine the spatial distributions of dark and luminous matter during the past 10 Gyr of cosmic history. The Euclid satellite was successfully launched on a SpaceX Falcon 9 launcher from Cape Canaveral on 1 July 2023 and is fully operational in a halo orbit around the Second Sun-Earth Lagrange point. We present an overview of the expected and unexpected findings during the early phases of the mission, in the context of technological heritage and lessons learnt. The first months of the mission were dedicated to the commissioning of the spacecraft, telescope and instruments, followed by a phase to verify the scientific performance and to carry out the in-orbit calibrations. We report that the key enabling scientific elements, the 1.2-meter telescope and the two scientific instruments, a visual imager (VIS) and a near-infrared spectrometer and photometer (NISP), show an inorbit performance in line with the expectations from ground tests. The scientific analysis of the observations from the Early Release Observations (ERO) program done before the start of the nominal mission showed sensitivities better than the prelaunch requirements. The nominal mission started in December 2023, and we allocated a 6-month early survey operations phase to closely monitor the performance of the sky survey. We conclude with an outlook of the activities for the remaining mission in the light of the in-orbit performance.

Euclid is a European Space Agency mission dedicated to the mapping of the dark Universe launched the 1st of July 2023. The mission will investigate the distance-redshift relationship and the evolution of cosmic structures. This is achieved by measuring shapes and redshifts of galaxies and clusters of galaxies up to 10 billion years away. Euclid makes use of two cosmological probes, in a wide survey over the full extragalactic sky: the Weak Gravitational Lensing (WL) and the Baryonic Acoustic Oscillations (BAOs). The WL is a method to map the dark matter and measure dark energy by measuring the apparent distortion of galaxy images by mass inhomogeneities along the line-of-sight. This probe requires extreme image quality thus constraining the optical system imaging quality and its characterization both on-ground and in-flight. The BAOs are wiggle patterns, imprinted in the clustering of galaxies, which provide a standard ruler to measure dark energy and the expansion in the Universe. The first images were released on the 7th of November 2023 showcasing the capabilities of the space segment. To achieve the stunning first images and the scientific objectives of the mission, the space segment (i.e. the spacecraft) underwent a thorough and extensive test campaign on-ground. These tests demonstrated the excellent image quality and the overall stability of both the payload and the spacecraft in a representative operational environment. In complement, further tests were performed during the commissioning phase, just after launch, to validate the spacecraft pointing stability.

Launched successfully on July 1st, 2023, Euclid, the M2 mission of the ESA cosmic vision program, aims mainly at understanding the origin of the accelerated expansion of the Universe. Along with a visible imager VIS, it is equipped with the NISP instrument, a Near Infrared Spectrometer and Photometer, bespoke tailored to perform a 3D mapping of the observable Universe. It operates in the near-infrared spectral range, from 900 nm to 2000 nm with 2 observing modes: as a spectrometer, the NISP instrument will permit measuring millions of galaxy spectroscopic redshifts over the 6.5 years lifetime of the Euclid mission; as a photometer, it will obtain photometric redshifts of billions of galaxies. This paper provides a description of the NISP instrument, its scientific objectives, and offers an assessment of its current performance in flight.

Due to the space radiation environment at L2, ESA’s Euclid mission will be subject to a large amount of highly energetic particles over its lifetime. These particles can cause damage to the detectors by creating defects in the silicon lattice. These defects degrade the returned image in several ways, one example being a degradation of the Charge Transfer Efficiency, which appears as readout trails in the image data. This can be problematic for the Euclid VIS instrument, which aims to measure the shapes of galaxies to a very high degree of accuracy. Using a special clocking technique called trap pumping, the single defects in the CCDs can be detected and characterised. Being the first instrument in space with this capability, it will provide novel insights into the creation and evolution of radiation-induced defects and give input to the radiation damage correction of the scientific data. We present the status of the radiation damage of the Euclid VIS CCDs and how it has evolved over the first year in space.

In November 2022, the ESA Science Programme Committee (SPC) selected ARRAKIHS as the second Fastimplementation mission (F2) within the Agency’s Scientific Programme, with a launch planned in 2030. ARRAKIHS is designed specifically to explore, at unprecedented depth, the predictions of the Λ-Cold Dark Matter (ΛCDM) cosmological model, and to assess the significance of reported tensions between model and observations in the local Universe. Through multi-band, ultra-low surface brightness imaging of the halos of a statistically representative sample of nearby Milky Waytype galaxies, ARRAKIHS will provide key tests with which to probe both the nature of Dark Matter in the Universe, and baryonic physics currently adopted in state-of-the-art galaxy formation models. This paper describes the ARRAKIHS mission concept and the main design and implementation challenges.

The Nancy Grace Roman Space Telescope (“Roman”) was prioritized by the 2010 Decadal Survey in Astronomy and Astrophysics and is NASA’s next astrophysics flagship Observatory. Launching no earlier than 2026, it will conduct several wide field and time domain surveys, as well as conduct an exoplanet census. Roman’s large field of view, agile survey capabilities, and excellent stability enable these objectives, yet present unique engineering and test challenges. The Roman Observatory comprises a Spacecraft and the Integrated Payload Assembly (IPA), the latter of which includes the Optical Telescope Assembly (OTA), the primary science Wide Field Instrument, a technology demonstration Coronagraph Instrument, and the Instrument Carrier, which meters the OTA to each instrument. The Spacecraft supports the IPA and includes the Bus, Solar Array Sun Shield, Outer Barrel Assembly, and Deployable Aperture Cover. It provides all required power, command handling, attitude control, communications, data storage, and stable thermal control functions as well as shading and straylight protection across the entire field of regard. This paper presents the Observatory as it begins integration and test, as well as describes key test and verification activities.

Surveys in space and time are key to answering outstanding questions in astrophysics. The power to study very large numbers of stars, galaxies, and transient events over large portions of the sky and different time scales has repeatedly led to new breakthroughs. The Nancy Grace Roman Space Telescope (Roman), NASA’s next Astrophysics Flagship mission, elevates wide field and time domain survey observations to previously inaccessible scales. Roman carries the Wide Field Instrument (WFI), which provides visible to near-infrared imaging and spectroscopy with an unprecedented combination of field-of-view, spatial resolution, and sensitivity. When combined with a highly stable observatory and efficient operations, the WFI allows surveys never before possible. These observations will lead to new discoveries in cosmology, exoplanets, and a very wide array of other astrophysics topics ranging from high redshift galaxies to small bodies in the solar system. This paper provides an overview of Roman survey science, connects this science to the design of the WFI, and provides a status update on WFI hardware build and test.

Slated for launch in 2025, SPHEREx will be NASA’s next astrophysics explorer mission. Optimized to meet rigorous requirements to precisely map the Universe’s large scale structure, produce deep maps of the diffuse extra-galactic background, and to survey the Milky Way’s biogenic ice content, the SPHEREx telescope’s widefield optical design utilizes a series of custom near infrared linear variable filters to survey the entire sky spectroscopically. This unique instrument has now completed its construction phase and is fully assembled for flight. To precisely focus and calibrate the optical and spectroscopic properties of SPHEREx, a custom optical-cryogenic facility was developed and commissioned. In this overview, we describe the implementation of the recently completed instrument integration and testing campaign, delivering a well characterized imaging spectrometer to be integrated with the rest of the observatory.

REX is a NASA Astrophysics Small Explorer Mission concept to chart the history of cosmic dawn in unprecedented detail in space and time. REX will identify very young galaxies and black holes by means of their powerful Lyman alpha (Lyα) line emission using about 10 narrow-bandpass filters covering about 100 square degrees. The strong line emission identifies samples of the most actively star-forming early galaxies, believed to be the drivers of reionization. Moreover, mapping the distribution and properties of the Lyman alpha emitting population will reveal the distribution of ionized and neutral gas, because neutral gas scatters Lyman alpha light, rendering them difficult to detect. REX will use an 0.5-1m telescope and 1 square degree field of view, tiled with HgCdTe detectors with development heritage from the Nancy Grace Roman Space Telescope. Its large, flexible filter complement will be used in a point-and-stare mode to identify Lyα emitting galaxies at a range of discrete redshift slices spanning the reionization era. In addition to its core reionization surveys, REX brings a new capability of tracing gas emission over large scales at the peak of star and black formation era. We will find millions of the youngest, least massive galaxies in epochs spanning the most active growth period of the universe. Applications will include ionized gas in nearby and distant galaxies, active galactic nuclei, and galaxy clusters. In summary, the REX survey will have the sensitivity and the area coverage to find the sites of earliest galaxy formation and will have the pixel size to enable good localization for follow up of individual galaxies with JWST and future telescopes.

The extragalactic background light (EBL) is the integrated diffuse emissions from unresolved stars, galaxies, and intergalactic matter along the line of sight. The EBL is regarded as consisting of stellar emissions and thus an important observational quantity for studying global star formation history throughout cosmic time. Intensity and anisotropy in the near-infrared EBL as measured by the Cosmic Infrared Background ExpeRiment (CIBER), NASA’s sounding rocket experiment, and previous infrared satellites exceed the predicted signal from galaxy clustering alone. The objective of CIBER-2 is to unveil the EBL excess by observing it at extended wavelengths into the visible spectrum with an accuracy better than CIBER. The onboard instrument of CIBER2 comprises a 28.5-cm telescope cooled to 90K, and three HAWAII-2RG detectors coupled with dual-band filters for photometric mapping observations in six wavebands simultaneously and with linear variable filters for lowresolution spectroscopy. Although CIBER-2 made a successful first flight from White Sands Missile Range in New Mexico in 2021, technical problems such as contamination of thermal radiation from the rocket chassis and degradation of the mirror coat were recognized. Despite a successful second flight in 2023 solving the problems with the revised onboard instrument, the experiment was aborted because of trouble with the rocket tracking system. In this paper, we describe the parachute-recovered payload rebuilt after the second flight and the testing, and we report the successful flight on May 5th 2024.

We describe scientific objective and project status of an astronomical 6U CubeSat mission VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat). The scientific goal of VERTECS is to reveal the star-formation history along the evolution of the universe by measuring the extragalactic background light (EBL) in the visible wavelength. Earlier observations have shown that the near-infrared EBL is several times brighter than integrated light of individual galaxies. As candidates for the excess light, first-generation stars in the early universe or low-redshift intra-halo light have been proposed. Since these objects are expected to show different emission spectra in visible wavelengths, multi-color visible observations are crucial to reveal the origin of the excess light. Since detection sensitivity of the EBL depends on the product of the telescope aperture and the field of view, it is possible to observe it with a small but wide-field telescope system that can be mounted on the limited volume of CubeSat. In VERTECS mission, we develop a 6U CubeSat equipped with a 3U-sized telescope optimized for observation of the visible EBL. The bus system composed of onboard computer, electric power system, communication subsystem, and structure is based on heritage of series of CubeSats developed at Kyushu Institute of Technology in combination with high-precision attitude control subsystem and deployable solar array paddle required for the mission. The VERTECS mission was selected for JAXA-Small Satellite Rush Program (JAXA-SMASH Program), a new program that encourages universities, private companies and JAXA to collaborate to realize small satellite missions utilizing commercial small launch opportunities, and to diversify transportation services in Japan. We started the satellite development in December 2022 and plan to launch the satellite in FY2025.

The extragalactic background light (EBL) is the integrated emission from all objects outside of the Milky Way galaxy and is a crucial observational quantity in the broader study of the history of cosmic structures. In the nearinfrared EBL, there have been measurements of an emission component several times brighter than the cumulative light from extragalactic galaxies. This unknown radiation component has led to proposals for candidate source objects, such as first stars and galactic halo brown dwarfs. These source objects exhibit distinct radiation spectra in the visible wavelength. The VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat) project is focused on continuously observing the visible EBL using a wide-field small telescope on a 6U CubeSat. The primary characteristic of this telescope is its high-throughput (SΩ > 10⁻⁶ m²sr). The 3U-sized optical telescope onboard this satellite consists of a lens optics with a total field of view of 6° × 6°, pixel field of view of 11” × 11”, a highly sensitive and low-noise detector module, and a baffle to eliminate stray light from the Sun and Earth. Additionally, color filters divide the wavelength range from 400 to 800 nm into four bands. Our observation strategy involves capturing 60-second exposure images while shifting the observed field by 3° increments and stacking the acquired images to perform photometry in the four bands. Thus far, most of the telescope design has met the required specifications, and the project is currently advancing towards the production of an engineering model. This project was selected in the JAXA-SMASH and is currently progressing in satellite development with a planned launch in the 2025 fiscal year. In this presentation, we will report on the strategy for observing the visible EBL, the progress in the development of the optical telescope, and the future plans.

GREX-PLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer) is one of the three candidates of ISAS/JAXA’s Strategic L-class mission for the 2030s. The 1.2 m aperture, 50 K cryogenic space telescope with the wide-field camera (WFC) will provide the 1,260 square arcmin field-of-view for five photometric bands between 2 and 8 μm. The high resolution spectrometer (HRS) will observe the 10–18 µm with a wavelength resolution of 30,000. The GREX-PLUS WFC field-of-view is 130 times larger than that of the James Webb Space Telescope and similar to those of Euclid and Roman Space Telescope. Since these two survey missions are limited to the wavelength less than around 2 µm, GREX-PLUS will extend the wavelength coverage beyond 2 μm, providing versatile legacy imaging survey significantly improved from previous Spitzer imaging survey in the same wavelength range. The spectral resolution of the GREX-PLUS HRS is 10 times higher than that of the James Webb Space Telescope, opening a new window of the mid-infrared high-resolution spectroscopy from space. The main scientific themes are the galaxy formation and evolution and the planetary system formation and evolution. The GREX-PLUS WFC aims to detect the first generation of “bright” galaxies at redshift z > 15. The GREX-PLUS HRS aims to resolve the Kepler motion of water vapor molecules and identify the location of the water “snowline” in ∼ 100 proto-planetary disks. Both instruments will provide unique data sets for a broad range of scientific topics including galaxy mass assembly, origin of super massive blackholes, infrared background radiation, molecular spectroscopy in the interstellar medium, transit spectroscopy for exoplanet atmosphere, planetary atmosphere in the Solar system, and so on. This paper presents the status of the concept design of GREX-PLUS, including telescope system, WFC, HRS, cooling system, and spacecraft bus system.

SIRMOS (Satellite for Infrared Multi-Object Spectroscopy) is a SMEX mission concept to map the universe in 3D over a cosmic volume of ~ 500 cubic gigaparsecs using 131 million H-alpha and [OIII] emission line galaxies (optimal for tracing cosmic large-scale structure) at 1 < z < 4. SIRMOS will probe the cosmic origin by placing unprecedented constraints on primordial non-Gaussianity, advance fundamental physics by precisely measuring the sum of neutrino masses, and definitively differentiate dark energy and modification of general relativity as the cause for the observed low-redshift cosmic acceleration. SIRMOS will measure galaxy evolution before and during the peak era of cosmic star formation over three orders of magnitude in environmental density, from cluster cores to cosmic filaments. SIRMOS has a 50 cm aperture telescope with 1.6 square degree FoV, and more than 4.4 million micromirrors on 2 digital micro-mirror devices (DMDs) to provide a programmable reflective slit mask allowing multi-slit spectroscopy at R~1300 over the wavelength range of 1.25 to 2.5 microns and a total survey area of 15,000 square degrees. The telescope is a modified Cassegrain followed by a prism mirror that splits the field toward 2 identical arms. Fore-optics reimage each subfield onto a DMD. The micro-mirrors in ON positions send the light to a spectrograph while those in OFF positions send the light to an imager which permits very precise measurements of the telescope pointing and everything not selected for spectroscopy.

Based on phase retrieval of defocused point source images from JWST commissioning, routine maintenance, and science data, we characterize components of the JWST OTE wavefront error variations over a wide range of time scales, including the accumulation of segment pose changes (tilt events) over days and weeks of typical wavefront control cycles, smooth drifts over hours and days, oscillation due to thermal cycling of the ISIM Electronics Compartment heaters with periods of a few minutes, and mechanical vibration modes with periods ~1 second and less. We extract the spatial and temporal forms of the detected WFE variations and explore correlation with relevant observatory telemetry data, including reaction wheel rotation speeds, IEC heater panel temperatures, and spacecraft attitude. This analysis extends the initial performance characterization during JWST commissioning and is intended to enhance the understanding and utility of JWST observations, as well as to provide more detailed in-flight characterization of optical stability for evaluation of integrated modeling and insight for the design and development of future observatories.

The Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope affords the astronomical community an unprecedented space-based Multi-Object Spectroscopy (MOS) capability through the use of a programmable array of micro-electro-mechanical shutters. Launched in December 2021 and commissioned along with a suite of other observatory instruments throughout the first half of 2022, NIRSpec has been carrying out scientific observations since the completion of commissioning. These observations would not be possible without a rigorous program of engineering operations to actively monitor and maintain NIRSpec’s hardware health and safety and enhance instrument efficiency and performance. Although MOS is only one of the observing modes available to users, the complexity and uniqueness of the Micro-Shutter Assembly (MSA) that enables it has presented a variety of engineering challenges, including the appearance of electrical shorts that produce contaminating glow in exposures. Despite these challenges, the NIRSpec Multi-Object Spectrograph continues to perform robustly with no discernible degradation or significant reduction in capability. This paper provides an overview of the NIRSpec micro-shutter subsystem’s state of health and operability and presents some of the developments that have taken place in its operation since the completion of instrument commissioning.

The Near Infrared Imager and Slitless Spectrograph (NIRISS) with its Single Object Slitless Spectrograph (SOSS) mode is a key instrument of the James Webb Space Telescope (JWST). This mode is optimized for exoplanet spectroscopy and time series observations of bright stars with J-band Vega magnitudes between 7 and 15 covering a broad wavelength range from 0.6 to 2.8 µm with a moderate spectral resolution (R ≈ 700 at 1.25 µm). In this work, we showcase some of the key efforts by the NIRISS/SOSS team to mitigate some unique aspects of this instrument. These include studying and predicting trace and wavelength solution movements as a function of small, visit-to-visit pupil wheel position variations, spectral extraction with spectral overlap, dispersed zodiacal light contamination, among others. We highlight the implementation of solutions to these challenges through publicly available code, as well as its integration into the JWST Calibration Pipeline. As more SOSS mode data becomes available and the instrument calibration improves, we continuously update observational resources and tools to help users optimize their science observations. We are committed to providing the community with advanced tools, code, and data models to aid in observational planning and data reduction, ensuring robust, science-grade data products through both the JWST calibration pipeline and user-developed pipelines.

Twinkle is one of the first in a series of innovative science satellites managed and operated by Blue Skies Space Ltd. The satellite design is based on a high-heritage Airbus platform, with a spectrometer designed by ABB Canada. The spacecraft will carry a 0.45 m telescope and a spectrometer that covers wavelengths from 0.5–4.5 𝜇m simultaneously. Placed in a thermally-stable, sun-synchronous, low-Earth orbit, the mission will operate for seven years and conduct large-scale survey programs. The first three years will focus on both Solar System and Extrasolar targets. This paper presents the satellite’s updated design, and key science themes developed by the Twinkle surveys’ members.

The Pandora SmallSat is a NASA flight project designed to study the atmospheres of exoplanets. Transmission spectroscopy of transiting exoplanets provides our best opportunity to identify the makeup of planetary atmospheres in the coming decade, and is a key science driver for HST and JWST. Stellar photospheric inhomogeneity due to star spots, however, has been shown to contaminate the observed spectra in these high-precision measurements. Pandora will address the problem of stellar contamination by collecting long-duration photometric observations sampled over a stellar rotation period with a visible-light channel and simultaneous spectra with a near-IR channel. These simultaneous multiwavelength observations will constrain star spot covering fractions of exoplanet host stars, enabling star and planet signals to be disentangled in transmission spectra to then reliably determine exoplanet atmosphere compositions. Pandora will observe exoplanets with sizes ranging from Earthsize to Jupiter-size and host stars spanning mid-K to late-M spectral types. Pandora was selected in early 2021 as part of NASA’s inaugural Astrophysics Pioneers Program. Herein, we present an overview of the mission, including the science objectives, operations, the observatory, science planning, and upcoming milestones as we prepare for launch readiness in 2025.

PLATO (PLAnetary Transits and Oscillations) mission is a space-based optical multi-camera photometer mission of the European Space Agency (ESA) to identify and characterize exoplanets and their hosting stars using two main techniques: planetary transit and asteroseismology. Selected as the M3 (third Medium class mission) of the ESA 2015-2025 Cosmic Vision program, PLATO is scheduled to launch end of 2026 and designed for 4 years of nominal observation. The PLATO spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the conventional spacecraft subsystems and the sun shield with attached solar arrays. The Payload Module consists of a highly stable optical bench, equipped with 26 optical cameras covering a global field of view of > 2232deg². The PLATO spacecraft data is complemented by ground-based observations and processed by a dedicated Science Ground Segment. We describe the mission and spacecraft architecture and provide a view of the current status of development.

PLATO (PLAnetary Transits and Oscillations of stars)1 is the M3 class ESA mission dedicated to the discovery and study of extrasolar planetary systems by means of planetary transits detection. PLATO Payload Camera units are integrated and vibrated at CSL before being TVAC tested for thermal acceptance and performance verification at 3 different test facilities (SRON, IAS and INTA). 15 of the 26 Flight Cameras were integrated, tested and delivered to ESA for integration by the Prime between June 2023 and June 2024, with the remaining flight units to be tested by the end of 2024. In this paper, we provide an overview of our serial testing approach, some of the associated challenges, key performance results and an up-to-date status on the remaining planned activities.

Leonardo SpA is leading an Italian Space Industry Team, funded by ASI, collaborating to the ESA mission PLATO program for the realization of the 26 telescopes, which will fly on a single platform, aimed to discover, observe and analyze the exoplanets. The mission is based on a challenging telescope design with peculiar optical performance to be assured at very low operative temperature (-80°C). The “large” number of telescopes, produced in high rate (up to 3 telescopes every 2 months), is quite unusual for the production of scientific payloads. It has imposed a change with respect the prototypical manufacturing and test approach, generally a few flight units for space equipment, addressing the implementation of smart and fast methodologies for aligning and focusing each telescope, based on simulation of the peculiar “as-built” data. The opto-mechanical design of the telescope has been optimized to implement an industrial approach for all the manufacturing, assembly, integration and test (MAIT) phases. The number, production rate and the performance results of the flight units so far delivered by Leonardo to the PLATO Consortium, are validating the selected design solutions and all the selected MAIT processes. All the units already delivered present very similar performance, full specs and very close to the theoretical design.

The Earth 2.0 (ET) space mission has entered its phase B study in China. It seeks to understand how frequently habitable Earth-like planets orbit solar-type stars (Earth 2.0s), the formation and evolution of terrestrial-like planets, and the origin of free-floating planets. The final design of ET includes six 28 cm diameter transit telescope systems, each with a field of view of 550 square degrees, and one 35 cm diameter microlensing telescope with a field of view of 4 square degrees. In transit mode, ET will continuously monitor over 2 million FGKM dwarfs in the original Kepler field and its neighboring fields for four years. Simultaneously, in microlensing mode, it will observe over 30 million I < 20.5 stars in the Galactic bulge direction. Simulations indicate that ET mission could identify approximately 40,000 new planets, including about 4,000 terrestrial-like planets across a wide range of orbital periods and in the interstellar space, ~1000 microlensing planets, ~10 Earth 2.0s and around 25 free-floating Earth mass planets. Coordinated observations with ground-based KMTNet telescopes will enable the measurement of masses for ~300 microlensing planets, helping determine the mass distribution functions of free-floating planets and cold planets. ET will operate from the Earth-Sun L2 halo orbit with a designed lifetime exceeding 4 years. The phase B study involves detailed design and engineering development of the transit and microlensing telescopes. Updates on this mission study are reported.

MIRASET (Mid-IR Array Spectrometer demonstration for Exoplanet Transits) is an ultra-stable laboratory spectrometer. Its purpose is to demonstrate a novel approach for isolating mid-infrared spectral lines detected in the atmospheres of transiting planets orbiting M-stars. Certain combinations of these spectral lines could potentially indicate the existence of life on these planets. To achieve this objective, we employ a black body source as a calibration standard, which also mimics the emission of an M-star in our lab setup. The power range of the black body emission can be adjusted to emit the same power on the detectors as would be observed from Proxima Cen B and Trappist-1 if they were observed using space-based observatories like ORIGINS or specialized MIR exoplanet missions like MIRECLE. All major elements in the experiment at all relevant stages can be temperature controlled, from the detector package, spectrometer, to the photo diode that monitors the output of the black body source in the visible, thereby measuring the temperature on the Wien side of the BB curve, which yields a higher temperature to emission ratio than in the MIR, which is on the Rayleigh Jeans part of the curve. With this experimental setup we have demonstrated the ability to monitor the black body emission over about an hour with a photometric precision of about 2 ppm in the MIR. Over more than 6 hours of integration, the noise floor still remains well below 5 ppm, which is the requirement for the detection of important atmospheric lines from earth-like planets around M-stars (~5 ppm).

Ariel, part of the European Space Agency's (ESA) Cosmic Vision science program, is an innovative medium-class mission designed for atmospheric remote sensing of exoplanets. It is the first mission solely dedicated to investigating the atmospheres of more than 500 transiting exoplanets, ranging from gas giants to super-Earths, using a combination of transit photometry and spectroscopy. The mission's primary goal is to analyze these exoplanets' chemical composition and thermal structures, paving the way for large-scale, comparative planetology. Ariel is scheduled for launch in 2029 aboard Ariane 6.2. It will operate from an orbit around the Sun-Earth system's second Lagrange point. The mission has a nominal lifetime of four years, with the potential for a two-year extension. The spacecraft comprises two main modules: the Service Module (SVM) and the Payload Module (PLM). The SVM manages platform elements, including attitude control, power, data handling, and communication systems. The PLM incorporates an all-aluminium cryogenic telescope with two scientific instruments, the Ariel IR Spectrometer (AIRS) and the Fine Guidance System (FGS). The Operational Ground Segment consists of ground stations and the Mission Operation Centre (MOC) located at ESOC, responsible for the operations of the spacecraft and instruments. The Science Ground Segment (SGS) consists of the Science Operation Centre (SOC), located at ESAC, along with the Instrument Operations and Science Data Centre (IOSDC) provided by the Ariel Mission Consortium (AMC). The SGS will perform the science mission planning as well as processing of the data to generate the mission data products and provision of the Ariel mission archive for the user community. While ESA holds overall responsibility for Ariel, the Ariel Mission Consortium is responsible for the procurement of the payload units, as well as managing the IOSDC. This collaborative effort aims to unlock the mysteries of exoplanetary atmospheres and deepen our understanding of these distant worlds.

The Ariel space mission will characterize spectroscopically the atmospheres of a large and diverse sample of hundreds of exoplanets. Through the study of targets with a wide range of planetary parameters (mass, density, equilibrium temperature) and host star types the origin for the diversity observed in known exoplanets will be better understood. Ariel is an ESA Medium class science mission (M4) with a spacecraft bus developed by industry under contract to ESA, and a Payload provided by a consortium of national funding agencies in ESA member states, plus contributions from NASA, the CSA and JAXA. The payload is based on a 1-meter class telescope operated at below 60K, built all in Aluminium, which feeds two science instruments. A multi-channel photometer and low-resolution spectrometer instrument (the FGS, Fine Guidance System instrument) operating from 0.5 – 1.95 microns in wavelength provides both guidance information for stabilizing the spacecraft pointing as well as vital scientific information from spectroscopy in the near-infrared and photometry in the visible channels. The Ariel InfraRed Spectrometer (AIRS) instrument provides medium resolution spectroscopy from 1.95 – 7.8 microns wavelength coverage over two instrument channels. Supporting subsystems provide the necessary mechanical, thermal and electronics support to the cryogenic payload. This paper presents the overall picture of the payload for the Ariel mission. The payload tightly integrates the design and analysis of the various payload elements (including for example the integrated STOP analysis of the Telescope and Common Optics) in order to allow the exacting photometric stability requirements for the mission to be met. The Ariel payload has passed through the Preliminary Design Review (completed in Q2 2023) and is now developing and building prototype models of the Telescope, Instruments and Subsystems (details of which will be provided in other contributions to this conference). This paper will present the current status of the development work and outline the future plans to complete the build and verification of the integrated payload.

Ariel (Atmospheric Remote-Sensing Infrared Exoplanet Large Survey) is the adopted M4 mission in the framework of the ESA “Cosmic Vision” program. Its purpose is to survey the atmospheres of known exoplanets through transit spectroscopy. The launch is scheduled for 2029. The scientific payload consists of an off-axis, unobscured Cassegrain telescope feeding a set of photometers and spectrometers in the waveband 0.5-7.8 µm and operating at cryogenic temperatures (55 K). The Telescope Assembly is based on an innovative fully aluminium design to tolerate thermal variations to avoid impacts on the optical performance; it consists of a primary parabolic mirror with an elliptical aperture of 1.1 m (the major axis), followed by a hyperbolic secondary that is mounted on a refocusing system, a parabolic re-collimating tertiary and a flat folding mirror directing the output beam parallel to the optical bench. An innovative mounting system based on 3 flexure hinges supports the primary mirror on one of the optical bench sides. The instrument bay on the other side of the optical bench houses the Ariel IR Spectrometer (AIRS) and the Fine Guidance System / NIR Spectrometer (FGS/NIRSpec). The Telescope Assembly is in phase B2 towards the Critical Design Review; the fabrication of the structural and engineering models has started; some components, i.e., the primary mirror and its mounting system are undergoing further qualification activities. This paper aims to update the scientific community on the progress concerning the development, manufacturing and qualification activity of the ARIEL Telescope Assembly.

AIRS is the infrared spectroscopic instrument of ARIEL: Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey mission adopted in November 2020 as the Cosmic Vision M4 ESA mission and planned to be launched in 2029 by an Ariane 6 from Kourou toward a large amplitude orbit around L2 for a 4-year mission. Within the scientific payload, AIRS will perform transit spectroscopy of over 1000 exoplanets to complete a statistical survey, including gas giants, Neptunes, super-Earths and Earth-size planets around a wide range of host stars. All these collected spectroscopic data will be a major asset to answer the key scientific questions addressed by this mission: what are exoplanets made of? How do planets and planetary systems form? How do planets and their atmospheres evolve over time? The AIRS instrument is based on two independent channels covering 1.95-3.90 µm (CH0) and 3.90-7.80 µm (CH1) wavelength ranges with prism-based dispersive elements producing spectra of low resolutions R>100 in CH0 and R>30 in CH1 on two independent detectors. The spectrometer is designed to provide a Nyquist-sampled spectrum in both spatial and spectral directions to limit the sensitivity of measurements to the jitter noise and intra pixels pattern during the long (10 hours) transit spectroscopy exposures. A full instrument overview will be presented covering the thermo-mechanical design of the instrument functioning in a 60 K environment, up to the detection and acquisition chain of both channels based on 2 HgCdTe detectors actively cooled to below 42 K. This overview will present updated information of phase C studies, in particular on the assembly and testing of prototypes that are highly representative of the future engineering model that will be used as an instrument-level qualification model.

The FGS is one of two scientific instruments on board the ESA ARIEL space telescope, which ESA plans to launch in 2029. The aim of the mission is to characterize the atmospheres of several hundred different exoplanets. The FGS is an opto-electronic instrument – a photometer and a near infra-red spectrometer. Although FGS stands for Fine Guidance System, in fact it has two main goals: to deliver scientific data of observed exoplanets, precisely speaking, their atmospheres, and to support the spacecraft’s AOCS with very precise pointing and guiding towards observation objects. This paper presents an overview of the current FGS design and implementation. The instrument is in the middle step between successfully passed iPDR and upcoming iCDR. Up to now, the team successfully built a prototype of the instrument, and is working on the manufacturing of the engineering and engineering-qualification models.

The Ariel space mission will characterize spectroscopically the atmospheres of a large and diverse sample of hundreds of exoplanets. Targets will be chosen to cover a wide range of masses, densities, equilibrium temperatures, and host stellar types to study the physical mechanisms behind the observed diversity in the population of known exoplanets. With a 1-m class telescope, Ariel will detect the atmospheric signatures from the small, < 100 ppm, modulation induced by exoplanets on the bright host-star signals, using transit, eclipse, and phase curve spectroscopy. Three photometric and three spectroscopic channels, with Nyquist sampled focal planes, simultaneously cover the 0.5-7.8 micron region of the electromagnetic spectrum, to maximize observing efficiency and to reduce systematics of astrophysical and instrumental origin. This contribution reviews the predicted Ariel performance as well as the design solutions implemented that will allow Ariel to reach the required sensitivity and control of systematics.

The James Webb Space Telescope is the first segmented observatory in space to conduct, among other things, high-contrast direct observations of exoplanetary systems. Such observations are thus to date the more technically akin to the future reconnaissance of nearby habitable zones with the Habitable Worlds Observatory. While JWST coronagraphs are not sensitive to temperate telluric planets, mostly due to the absence of critical Deformable Mirrors that will fly on the Roman Coronagraph Instrument (CGI), their capabilities are have achieved a few milestones relevant to HWO. This paper is part of a series to be presented by the JWST Telescope Scientist Team, JWST-TST. A common theme of these investigations is the desire to pursue and demonstrate science for the astronomical community at the limits of what is made possible by the exquisite op- tics and stability of JWST. The high-contrast programs of TST were crafted to rapidly advance knowledge of high-contrast strategies and best practices with JWST early in the mission. In this paper, we summarize our results and discuss their implications for the ongoing HWO architecture formulation.

The Coronagraph Instrument on the Nancy Grace Roman Space Telescope is a critical technology demonstrator for NASA’s Habitable Worlds Observatory. It recently successfully completed all the required instrument-level functional, environmental, and performance tests. This paper will review the coronagraph instrument system, the final test results, and the plans for coronagraph integration with the Roman Space Telescope.

In preparation for the operational phase of the Nancy Grace Roman Space Telescope, NASA has created the Coronagraph Community Participation Program (CPP) to prepare for and execute Coronagraph Instrument technology demonstration observations. The CPP is composed of 7 small, US-based teams, selected competitively via the Nancy Grace Roman Space Telescope Research and Support Participation Opportunity, members of the Roman Project Team, and international partner teams from ESA, JAXA, CNES, and the Max Planck Institute for Astronomy. The primary goals of the CPP are to prepare simulation tools, target databases, and data reduction software for the execution of the Coronagraph Instrument observation phase. Here, we present the current status of the CPP and its working groups, along with plans for future CPP activities up through Roman’s launch. We also discuss plans to potentially enable future commissioning of currently-unsupported modes.

NASA’s Habitable Worlds Observatory (HWO) mission is intended to search for biosignatures from ~25 exoplanets in the habitable zones of their host stars using a coronagraph instrument. This requires the coronagraph to directly detect and spectrally analyze photons from planets that are merely ~ 0.1 arcsec from the host star and ~ 10 billion times fainter. Achieving extreme contrast levels at extremely small angular separations is a daunting technological challenge. A working group of 50+ multi-institutional experts has been developing a first cut at a coronagraph technology roadmap to identify key technology gaps and enabling technology developments for HWO’s coronagraph instrument system. This paper will present a summary of the working group’s findings.

NASA’s Habitable Worlds Observatory will consist of a segmented telescope and high contrast coronagraph to characterize exoplanets for habitability. Achieving this objective requires an ultra-stable telescope with wavefront stability of picometers in certain critical modes. The NASA funded Ultra-Stable Large Telescope Research and Analysis – Technology Maturation program has matured key component-level technologies in 10 areas spanning an “ultra-stable” architecture, including active components like segment edge sensors, actuators and thermal hardware, passive components like low distortion mirrors and stable structures, and supporting capabilities like precision metrology. This paper will summarize the final results from the four-year ULTRA-TM program, including advancements in performance and/or path-to-flight readiness, TRL/MRL maturation, and recommendations for future work.

The Deformable Mirror (DM) Technology Roadmap (DMTR) working group is a team tasked by NASA’s Exoplanet Exploration Program Office (ExEp) with studying the path to bring deformable mirror systems to a Technology Readiness Level (TRL) 5. It is operating jointly with Coronagraph Architecture Study and Coronagraph Technology Roadmap working groups to inform the newly formed Habitable Worlds (HabWorlds) Observatory (HWO) Technology Assessment Group (TAG) and Science, Technology, Architecture Review Team (START). DMs are the critical component of any exoplanet direct imaging coronagraph, and there is no device that exists today which can meet the ambitious requirements expected for HWO. The objective of the DMTR is to survey the field of DM technologies, define a baseline set of device requirements from which we can iterate on a development plan with vendors, and recommend a development and verification program. The purpose is to provide a more mature starting point for the future HWO technology development plans. To that end, the DMTR effort builds on the HabEx and LUVOIR decadal studies, as well as the flight development experience of Roman Coronagraph Instrument. The key deliverable is a general TRL development architecture, and assessments of cost, schedule, and risks for all vendors to the extent they are able to engage in the study. In this effort we consider the TRL of the DM as a system, meaning the device, drive electronics, and harnessing. This is an important distinction since TRL-5 is only achieved by demonstrating that the system meets performance requirements with a form and fit that matches a flight-worthy device subjected to relevant environments. Here we present progress on our development of validation plan for HWO DM system technologies.

This talk will discuss the science activities associated with these studies performed by the Science, Technology, and Architecture Review Team (START) for the Habitable Worlds Observatory, including the team and organization, and with a focus on identifying those key science drivers which inform trades that will lead to architecture choices as the mission enters the Pre-Phase A stage and beyond.

NASA began the Great Observatory Maturation Program (GOMAP) with the goal of studying and advancing the Habitable Worlds Observatory (HWO), a large ultraviolet, optical, infrared space telescope recommended by the Astro 2020 Decadal Survey. Among its many goals, HWO will obtain spectra of at least 25 exo-Earth candidates to search for signs of life and conduct transformative astrophysics at ultraviolet, optical, and near-infrared wavelengths. The observatory, like HST and JWST, will be a powerful general class observatory. This past fall the GOMAP program stood up two study groups, the Science Technology Architecture Review Team (START) and the Technical Assessment Group (TAG) aimed at helping to study the science, technology and architecture options for this new flagship mission. This talk will discuss the engineering activities associated with these studies including the team and organization, the study plan and the use of the Concept Maturity Level (CML) approach. In addition, the talk will discuss the key initial engineering efforts, the key technology gaps, and overall engineering plans.

Modeling played a vital role on the James Webb Space Telescope (JWST) program. From early modeling to aid in requirements development to final verification and on-orbit performance determination, modeling evolved and grew as the program progressed. With the heavy reliance on modeling that large, complex missions like JWST has had and Habitable Worlds Observatory (HWO) will have, enabling accurate and timely modeling results as the design matures is extremely important. This paper will discuss the types of modeling necessary and the lessons learned during the development of JWST that are applicable to HWO.

The Habitable Worlds Observatory will have uniquely stringent wavefront stability requirements, in the single-digit picometers for observations lasting days, to preserve coronagraph contrast for imaging earth-like exoplanets. This need will be addressed using high-precision Wavefront Sensing and Control methods, including continuous picometerprecision metrology and control of the Optical Telescope Assembly (OTA). This paper reviews methods for initializing and maintaining the OTA wavefront, evolved from those used for the James Webb Space Telescope, but extended to much higher precision. It concludes by identifying performance targets for WFSC technology development, to help guide NASA technology investments.

The Astro2020 Decadal Survey recommends an ambitious mission named Habitable Worlds Observatory (HWO) to explore the universe and search for life on exoplanets. HWO builds upon NASA investments, including the James Webb Space Telescope segmented optical system, Roman Space Telescope coronagraph, large mission concept studies, and technology development. Studies continue to drive our understanding of the HWO mission trade space and increase the readiness of relevant technologies. NASA’s Great Observatory Maturation Program (GOMAP) will explain how mission architecture decisions impact science yields and improve understanding of the boundaries and opportunities within the mission trade spaces.

The Habitable Worlds Observatory will revolutionize our understanding of the universe by directly detecting biosignatures on extrasolar planets and allow us to answer the question if we are alone in the universe. To accomplish the tight science goals associated with this mission, the development of an ultrastable observatory with a coronagraphic instrument is necessary. The observatory itself may need to stay stable on the order of 10 picometers over a wavefront control cycle, orders of magnitude more stable than what is required on current space missions. The metrology to verify stability requirements must be roughly a factor of ten more stable. The ultrastable laboratory at NASA’s Goddard Space Flight Center has further stabilized its testbed to allow for dynamic measurements on diffuse and specular objects on the order of single picometers, and we are currently measuring drifts on the orders of tens of picometers over different temporal bands. This paper will discuss the mechanical updates to the testbed setup, the analysis performed on several test articles, and the path forward on the road to measuring achieving the required stability for Habitable Worlds Observatory.

Theoretical ideal coronagraph performance is achieved when the light from an exoplanet can be coherently decomposed into a linear combination of spatial modes indistinguishable from that containing starlight, and an orthogonal mode. The intensity in the exoplanet mode orthogonal from the stellar modes as a function of separation from the star represents theoretical ideal coronagraph performance. Here we introduce a photonic coronagraph architecture capable of achieving this near-ideal exoplanet throughput at small inner working angles. We will review progress at the NASA Jet Propulsion Lab on prototype hardware implementing this photonic coronagraph concept and discuss our progress at device calibration and closed-loop control required for a photonic coronagraph in a changing wavefront environment.

The Habitable Worlds Observatory (HWO) is the leading recommendation of the Astro2020 decadal survey. The HWO flagship, to be launched in the early 2040s, will directly survey 100 of the nearest stellar systems and their habitable zones with the goal of detecting and spectroscopically characterizing 25 potentially “Earth-like planets” (or “Exo-Earths”). Photonic-based technologies can substantially improve technical and science margins by improving coronagraphic efficiency for HWO. We present the architecture of a photonic-integrated circuit (PIC)-based coronagraph (“AstroPIC”), currently being studied as a near-infrared channel coronagraph that can be adopted as part of a suite of coronagraphs that could be deployed on the HWO. The PIC architecture miniaturizes a traditional coronagraph reducing the mass and volume of the coronagraph while providing an avenue to simply enhance the functionality, bandwidth coverage, and exoplanet yield of HWO by adopting a Mach-Zehnder Interferometric (MZI) mesh for photonic nulling. In this architecture we consider two cases: (1) a hybrid AstroPIC using a small number of modes (16-25) can still enhance exoplanet yields through complementary coronagraphic sensitivities to a traditional coronagraph, and (2) a full photonic chip AstroPIC that uses larger number of modes (400+) that can be operated as a stand-alone coronagraph that approaches the optimal coronagraph performance limit. We summarize recent experiments carried out at the Stanford photonic teststand which demonstrate key coronagraphic functionality including: (1) 1e-7 contrast (70 dB nulling) achieved with a simple PIC consisting of a 4-MZI mesh, (2) 8e-9 contrast (81 dB nulling) achieved with 6-MZI elements, and (3) a free-space coupling on chip of a beam demonstrating coronagraphic nulling and coronagraphic throughput of an off-axis source. We discuss the recent AstroPIC Cycle-1 tape-out which will enable additional coronagraphic demonstrations including deeper nulling and scaling to larger numbers of modes initiating a technology development process to mature PIC-based coronagraphy for inclusion into HWO.

The Habitable Worlds Observatory (HWO) aims for high-contrast imaging of exoplanets, targeting 1e-10 contrasts. Current coronagraph designs fall short of the fundamental coronagraphic limit, providing an opportunity for increasing the science yield of HWO. Photonic integrated circuits (PICs) are in theory able to achieve the fundamental limit. However, manufacturing errors in PICs introduce modal crosstalk, degrading contrast. To address this, we use a traditional PIAACMC coronagraph as a pre-filter before injection into the PIC. The entire system is optimized for its coronagraphic performance. We show initial simulations of this hybrid coronagraph for unobscured and obscured telescope pupils, with a focus on circuit design and active tuning algorithms for the PIC.

High Contrast Imaging systems (HCIs) must simultaneously optimize contrast, throughput, inner working angle, and angular resolution. HCIs must also be resilient to residual wavefront errors (WFEs), which is achieved by coronagraph design (low sensitivity to WFEs), active control (WFEs are suppressed) and self-calibration (the contribution of WFEs to residual starlight is accurately known and numerically removed). We establish a process for designing optimal HCIs considering resilience to WFEs, from which we derive fundamental performance limits in the presence of wavefront errors. We show that a discretized version of an optimal HCI system can be realized as a photonic nulling chip (PNC), an approach providing more design flexibility than is accessible with coronagraph masks. We demonstrate on-sky self-calibration capability with the PNC-based GLINT instrument at the Subaru Telescope, and discuss future developments for ground and space-based HCI.

One of the primary science goals of the Habitable Worlds Observatory (HWO) as defined by the Astro2020 decadal survey is the imaging of the first Earth-like planet around a Sun-like star. A key technology gap towards reaching this goal are the development of ultra-low-noise photon counting detectors capable of measuring the incredibly low count rates coming from these planets which are at contrasts of ∼ 1 × 10⁻¹⁰. Superconducting energyresolving detectors (ERDs) are a promising technology for this purpose as, despite their technological challenges, needing to be cooled below their superconducting transition temperature (< 1K), they have essentially zero read noise, dark current, or clock-induced charge, and can get the wavelength of each incident photon without the use of additional throughput-reducing filters or gratings that spread light over many pixels. The use of these detectors on HWO will not only impact the science of the mission by decreasing the required exposure times for exo-Earth detection and characterization, but also in a wavefront sensing and control context when used for starlight suppression to generate a dark zone. We show simulated results using both an EMCCD and an ERD to “dig a dark zone” demonstrating that ERDs can achieve the same final contrast as an EMCCD in about half of the total time. We also perform a simple case study using an exposure time calculator tool called the Error Budget Software (EBS) to determine the required integration times to detect water for HWO targets of interest using both EMCCDs and ERDs. This shows that once a dark zone is achieved, using an ERD can decrease these exposure times by factors of 1.5–2 depending on the specific host star properties.

Deformable mirrors (DMs) are a critical technology to enable coronagraphic direct imaging of exoplanets with current and planned ground- and space-based telescopes as well as future mission concepts, such as the Habitable Worlds Observatory (HWO), which aims to image exoplanet types ranging from gas giants to Earth analogs. These missions set several requirements on the DMs such as large actuator count (≥96×96) and resolution smaller than 2.5 pm. This paper presents the first demonstration of single-picometer wavefront control utilizing a new high-resolution, vacuum-compatible DM electronics and a Zernike Wavefront Sensor for measurement. The controller can handle 2,040 actuators with 125 V maximum voltage with 20-bit resolution, resulting in voltage steps of 119 microvolts that allowed us to demonstrate 0.65 pm resolution of the DM surface.

Starlight suppression to levels of contrast of 1×10⁻¹⁰ with an internal coronagraph would allow for detection and spectral characterization of Earth-analogs. Many coronagraph architectures have been proposed to address this science case. Among them, the vector vortex coronagraph (VVC) stands out for its exquisite sensitivity especially at small angular separations. However, the VVC has yet to demonstrate 1×10⁻¹⁰ contrast in the laboratory. The limitation of VVCs with respect to the Lyot Coronagraph, which holds the contrast record, has been thought to be the vortex mask. Indeed, the mask fabrication imperfections limit how well the deformable mirrors can suppress starlight in the image during wavefront control. Furthermore, the polarization leakage inherent to the VVC has not been fully addressed as a source of incoherent light that limits this type of coronagraph’s performance. Our new experiments in the Decadal Survey Testbed confirm these suspicions. Here we present the results of these experiments with a comprehensive characterization of our two best VVC masks.

We present the final results of the Apodized Pupil Lyot Coronagraph (APLC) on the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed, under NASA’s Strategic Astrophysics Technology program. The HiCAT testbed was developed over the past decade to enable a system-level demonstration of coronagraphy for exoplanet direct imaging with the future Habitable Wolds Observatory. HiCAT includes an active, segmented telescope simulator, a coronagraph, and metrology systems (Low-order and Mid-Order Zernike Wavefront Sensors, and Phase Retrieval camera). These results correspond to an off-axis (un-obscured) configuration, as was envisioned in the 2020 Decadal Survey Recommendations. Narrowband and broadband dark holes are generated using two continuous deformable mirrors (DM) to control high order wavefront aberrations, and low-order drifts can be further stabilized using the LOWFS loop. The APLC apodizers, manufactured using carbon nanotubes, were optimized for broadband performance and include the calibrated geometric aperture. The objectives of this SAT program were organized in three milestones to reach a system-like level demonstration of segmented-aperture coronagraphy, from static component demonstration to system-level demonstration under both natural and artificial disturbances. HiCAT is, to this date, the only testbed facility able to demonstrate high-contrast coronagraphy with a truly segmented aperture, as is required for the Habitable World Observatory, albeit limited to ambient conditions, corresponding to NASA’s Technology Readiness Level (TRL) 4. Results presented here include 6 × 10⁻⁸ (90% CI) contrast in 9% bandpass in a 360 deg dark hole with inner and outer working angles of 4.4λ/D_pupil and 11λ/D_pupil. Narrowband contrast (3% bandpass) reaches 2.4 × 10⁻⁸ (90% confidence interval). We first explore the open-loop stability of the entire system quantify the baseline testbed performance. Then we present dark hole stabilization using both high-order and low-order loops under both low-order and segment level drifts in narrow and broadband. We compare experimental data with that obtained by the end-to-end HiCAT simulator. We establish that current performance limitations are due to a combination of ambient conditions, detector and deformable mirrors noises (including quantization), and model mismatch.

We have built a laboratory testbed called the Exoplanet Imaging System Testbed (EXIST) to develop future highcontrast imaging technologies. The main objective of the EXIST is the development of broadband coronagraph and wavefront control techniques. The EXIST is equipped with several fiber-coupled laser and broadband light sources to model star and planets. A spatial light modulator (SLM) is used to carry out the wavefront control in front of the coronagraph. We incorporated a variety of coronagraphic masks, including four-quadrant, eightoctant, and 12-sector phase masks. These masks exhibit second-, fourth-, and sixth-order starlight suppression properties, respectively. When combined with the wavefront control, higher-order coronagraphic masks provided better dark hole contrast. This paper reports on recent experimental results and prospects for future technological development at the EXIST.

Directly imaging Earth-like exoplanets around Sun-like stars with the future Habitable Worlds Observatory (HWO) will require coronagraphic focal plane masks able to suppress starlight to the 1 × 10⁻¹⁰ contrast levels. Furthermore, to collect enough photons for broadband imaging and detection and to minimize the number of parallel channels for spectroscopic characterization, this level of contrast must be achieved across a 20% bandwidth. Scalar vortex coronagraphs show promise as a polarization-independent alternative to polarizationsensitive vector vortex coronagraphs, but still face chromatic limitations. New scalar vortex mask designs incorporate radial phase dimples to improve the broadband performance. We present initial manufacturing results of prototype masks of these designs including phase metrology and microscope images, in preparation for broadband chromatic characterization and starlight suppression measurements, to be taken on a high contrast imaging testbed. We also present a preliminary narrowband (2%) dark hole result achieving 1.8 × 10⁻⁸ average contrast from 3.5-10λ₀/D on the High Contrast Spectroscopy Testbed at Caltech. This work aims to advance the technological maturity of scalar vortex coronagraphs as a viable option for consideration for HWO.

The Space Coronagraph Optical Bench (SCoOB) is a high-contrast imaging testbed built to demonstrate starlight suppression techniques at visible wavelengths in a space-like vacuum environment. The testbed is designed to achieve <10⁻⁸ contrast from 3 − 10λ/D in a one-sided dark hole using a liquid crystal vector vortex waveplate and a 952-actuator Kilo-C deformable mirror (DM) from Boston Micromachines (BMC). We have recently expanded the testbed to include a field stop for mitigation of stray/scattered light, a precision-fabricated pinhole in the source simulator, a Minus K passive vibration isolation table for jitter reduction, and a low-noise vacuum-compatible CMOS sensor. We report the latest contrast performance achieved using implicit electric field conjugation (iEFC) at a vacuum of ∼10⁻⁶ Torr and over a range of bandpasses with central wavelengths from 500 to 650nm and bandwidths (BW) from ≪ 1% to 15%. Our jitter in vacuum is < 3 × 10⁻³λ/D, and the best contrast performance to-date in a half-sided D-shaped dark hole is 2.2 × 10⁻⁹ in a ≪ 1% BW, 4 × 10⁻⁹ in a 2% BW, and 2.5 × 10⁻⁸ in a 15% BW.

We present simulated results for the Phase Induced Amplitude Apodization (PIAA)-Vortex coronagraph for on-axis telescope architectures. In previous studies, we demonstrated that the PIAA-Vortex coronagraph has the potential to overcome limitations on coronagraph performance for on-axis telescopes, and can maintain insensitivity to stellar angular diameters on the order of 0.1 λ/D at a contrast of 10⁻¹⁰. Here, we present designs for the PIAA-Vortex coronagraph optimized for a segmented, on-axis telescope aperture that creates a 10⁻¹⁰ - contrast, broadband dark zone with a 20% bandwidth and an inner working angle of 2.5 λ/D. These designs are part of ongoing modelling work. We show that the Earthlike exoplanet yield of the design presented here reduces the performance gap between on-axis and off-axis coronagraphy, and describe preliminary results which increase the throughput, aberration sensitivity, and overall yield of the coronagraph further. The PIAA-Vortex coronagraph will contribute to enabling consideration of obstructed telescope pupils for the Habitable Worlds Observatory, thereby taking advantage of previous NASA optical observatory heritage and potentially allowing for greater flexibility in observatory design.

With the commencement of the development of the Habitable Worlds Observatory, it is imperative that the community has an understanding of (1) the stability requirements for the observatory to inform the design and (2) the gains expected from post-processing to inform observing scenarios and science yield estimates. We demonstrate that a previously developed, photon-efficient dark-zone maintenance (DZM) algorithm, that corrects quasi-static wavefront error drifts by using only science images, is compatible with traditional post-processing techniques. Further, we augment the DZM algorithm to estimate the coherent and incoherent light separately and introduce three novel post-processing techniques that leverage the concurrent estimation of coherent and incoherent light. With the DZM algorithm implemented on the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed at the Space Telescope Science Institute (STScI), artificial drifts are injected as a random walk on a set of deformable mirrors (DMs) and are corrected with DZM. An injected fake planet is recovered in post-processing using a variety of techniques, such as angular differential imaging (ADI), and three novel techniques presented in this paper: incoherent accumulated imaging (IAI), software-based coherent differential imaging (CDI), and coherent reference differential imaging (CoRDI). All post-processing techniques can recover an injected planet at the same contrast level as the dark-zone background contrast (∼ 8 × 10⁻⁸), and the ADI technique is shown to recover a 4 × 10⁻⁸ planet in a 8 × 10⁻⁸ dark zone. For a space-based observatory, this would mean that if the instrument can reach a contrast level, we can maintain it and recover a planet that is undetectable in a single frame.

Direct detection of Earth-like exoplanets requires a high-contrast imaging system to suppress bright stellar light that prevents the detection. The wavefront sensing and control technique which is one component of the high-contrast imaging system can suppress stellar scattered light (speckles) caused by wavefront aberrations. However, deformation of the system due to temperature changes in space telescopes or atmospheric turbulence in ground-based telescopes cause speckles that fluctuate faster than the wavefront sensing and control. As the post-processing technique, the Coherent Differential Imaging on Speckle Area Nulling (CDI-SAN) method was proposed to suppress the fast-fluctuating speckles. We are conducting the laboratory demonstration of the CDISAN method using two types of experimental facilities. One of them is equipped with a deformable mirror and a field programmable gate array. In our initial laboratory demonstration, we achieved 10⁻⁸ level contrast. To achieve higher contrast, we are updating our facility. The other facility is equipped with a spatial light modulator (SLM). In this facility, the contrast was improved by 10⁻¹ using the CDI-SAN method.

Stellar coronagraphs use closed-loop focal-plane wavefront sensing and control algorithms to create high-contrast dark zones suitable for imaging exoplanets and exozodiacal dust clouds around nearby stars. Model-based algorithms are susceptible to model mismatch, wherein a departure of the coronagraph's true optical characteristics from the assumed model causes reduced control loop performance. Here, we report on a collection of techniques, including prediction-error minimization, expectation-maximization, and maximum-likelihood estimation, for empirically tuning the wavefront control Jacobian matrix in a statistically rigorous fashion during closed-loop wavefront control operations. This mitigates model mismatch and recovers near-optimal control loop performance.

This paper presents initial results from the ESA-funded “SUPPPPRESS” project, which aims to develop highperformance liquid-crystal coronagraphs for direct imaging of Earth-like exoplanets in reflected light. The project focuses on addressing the significant challenge of polarization leakage in vector vortex coronagraphs (VVCs). We utilize newly manufactured multi-grating, liquid-crystal VVCs, consisting of a two- or three-element stack of vortex and grating patterns, to reduce this leakage to the 10⁻¹⁰ contrast level. We detail the experimental setups, including calibration techniques with polarization microscopes and Mueller matrix ellipsometers to enhance the direct-write accuracy of the liquid-crystal patterns. The performance testing of these coronagraph masks will be conducted on the THD2 high-contrast imaging testbed in Paris.

LiteBIRD, the next-generation cosmic microwave background (CMB) experiment, aims for a launch in Japan’s fiscal year 2032, marking a major advancement in the exploration of primordial cosmology and fundamental physics. Orbiting the Sun-Earth Lagrangian point L2, this JAXA-led strategic L-class mission will conduct a comprehensive mapping of the CMB polarization across the entire sky. During its 3-year mission, LiteBIRD will employ three telescopes within 15 unique frequency bands (ranging from 34 through 448 GHz), targeting a sensitivity of 2.2 μK-arcmin and a resolution of 0.5° at 100 GHz. Its primary goal is to measure the tensor-toscalar ratio r with an uncertainty δr = 0.001, including systematic errors and margin. If r ≥ 0.01, LiteBIRD expects to achieve a > 5σ detection in the ℓ = 2–10 and ℓ = 11–200 ranges separately, providing crucial insight into the early Universe. We describe LiteBIRD’s scientific objectives, the application of systems engineering to mission requirements, the anticipated scientific impact, and the operations and scanning strategies vital to minimizing systematic effects. We will also highlight LiteBIRD’s synergies with concurrent CMB projects.

LiteBIRD is a JAXA-led international project aimed to make high sensitivity measurements of the primordial B modes through cosmic microwave background (CMB) polarization observations. The Low-Frequency Telescope (LFT) is a modified crossed Dragone reflective telescope with a 18° × 9° field-of-view across the 34-161 GHz. To achieve the required observational sensitivity, the telescope’s sidelobe response must be characterized to high precision to minimize signal contamination systematic effects from galactic and foreground emission. We report on the development of LFT optical simulation models that include the reflector optics, optimized serrations, finite absorptivity baffling, and V-grooves, and characterize the LFT sidelobes accounting for multiple reflection and diffraction optical effects. We find that the implementation of triangular and cos² shaped serrations on the primary and secondary reflectors are effective in reducing asymmetric sidelobe power fluctuations to ≤ 1.42×10−4 and ≤ 1.20 × 10⁻⁴, respectively, at 34 GHz at 5.5° ≤ θbeam ≤ 35° from the beam center. Without telescope baffling, the LFT optics show prominent direct sidelobe and diffuse triple reflection sidelobes with peak powers of ≤ −35.49 dB and ≤ −38.65 dB, respectively. It was found that implementing a finite absorptivity focal plane (FP) hood and forebaffle allows for effectively mitigating these sidelobes to ≤ −58.66 dB at 34 and 42 GHz for θ > 45° from boresight. Further including V-grooves in the optical simulation model, it was found that the V-grooves attenuate the far sidelobe power at El < −50° to ≤ −74.8 dB. All these far-sidelobe features are found to be below the LiteBIRD sidelobe knowledge requirement levels.

Recent advancements in imaging the magnetic field in the interstellar medium (ISM) have been made using instruments like PILOT, NIKA2, and HAWC+. These instruments, operating in submillimeter and millimeter domains, have revealed that the magnetic field tends to be orthogonal to the filamentary structures in star-forming regions of the ISM. However, further observations with higher spatial resolution are needed to better understand the physical processes in these areas. An upgraded version of the BBOP instrument, initially developed for the SPICA mission, is proposed for future large aperture space observatories. This enhanced BBOP features three bolometer arrays sensitive to 100, 220, and 350-micron spectral bands. These silicon bolometers offer significantly improved sensitivity and polarimetric capabilities. Each pixel can detect two orthogonal polarization components, and the bolometer arrays operate at 50 mK with a differential read-out scheme. This allows simultaneous measurement of both total light intensity and polarization for each pixel. The presentation will cover the instrument's concept, design, estimated performance, and initial laboratory tests.

The HiZ-GUNDAM is a time-domain and multi-messenger astronomy mission by monitoring high-energy astronomical transient events such as gamma-ray bursts (GRBs). The HiZ-GUNDAM is designed to provide alerts of high-redshift GRBs with wide field X-ray monitors (WFXMs) and a co-onboard 30-cm optical and near-infrared telescope (NIRT) for immediate photometric follow-up observations. The HiZ-GUNDAM satellite automatically changes its attitude toward the discovered transient object, starts the follow-up observations with NIRT, and sends alert information including the detailed position, the apparent magnitude, and the photometric redshift of the transient object within one hour. This mission was selected as one of the mission concept candidates of the competitively-chosen medium-class mission of ISAS/JAXA. Aiming for launch in 2030s, conceptual studies of the satellite and onboard instruments are currently ongoing. The five-band simultaneous observation at 0.5-2.5 μm is realized by a beam splitter and a Kösters prism. The incoming beam is split into visible light (0.5-0.9 µm) and near-infrared light by the beam splitter, and visible light is received by an optical detector. The near-infrared light is additionally split into four bands (0.9-1.3 μm, 1.3-1.7 μm, 1.7-2.1 μm, and 2.1-2.5 μm, respectively) by the Kösters prism, and received by an infrared detector. The telescope, the beam-splitter, the Kösters prism, and the optical detector are cooled down to <200 K, and the infrared detector is additionally cooled down to <120 K by radiation cooling. All mirrors in the telescope are made of aluminum alloy to reduce alignment errors during cooling. In this presentation, we introduce the current status of the development of NIRT onboard HiZ-GUNDAM.

The study of the universe through gravitational waves will yield a revolutionary new perspective on the universe, which has been intensely studied using electromagnetic waves in many wavelength bands. A space based gravitational wave observatory will enable access to a rich array of astrophysical sources in the measurement band from 0.1 mHz to 1 Hz. A space based mission complements ground based gravitational wave observatories, which typically search for signals at higher frequencies. LISA is a space based gravitational wave mission. Telescopes are one of the technology contributions from NASA to the European Space Agency (ESA) for the Laser Interferometer Space Antenna (LISA) Mission. ESA adopted the LISA mission in January of 2024. We will describe the key requirements for the flight telescopes and summarize the current status of the technology development effort.

We present the Black Hole Explorer (BHEX), a mission that will produce the sharpest images in the history of astronomy by extending submillimeter Very-Long-Baseline Interferometry (VLBI) to space. BHEX will discover and measure the bright and narrow “photon ring” that is predicted to exist in images of black holes, produced from light that has orbited the black hole before escaping. This discovery will expose universal features of a black hole’s spacetime that are distinct from the complex astrophysics of the emitting plasma, allowing the first direct measurements of a supermassive black hole’s spin. In addition to studying the properties of the nearby supermassive black holes M87∗ and Sgr A∗ , BHEX will measure the properties of dozens of additional supermassive black holes, providing crucial insights into the processes that drive their creation and growth. BHEX will also connect these supermassive black holes to their relativistic jets, elucidating the power source for the brightest and most efficient engines in the universe. BHEX will address fundamental open questions in the physics and astrophysics of black holes that cannot be answered without submillimeter space VLBI. The mission is enabled by recent technological breakthroughs, including the development of ultra-high-speed downlink using laser communications, and it leverages billions of dollars of existing ground infrastructure. We present the motivation for BHEX, its science goals and associated requirements, and the pathway to launch within the next decade.

The Black Hole Explorer (BHEX) is a next-generation space very long baseline interferometry (VLBI) mission concept that will extend the ground-based millimeter/submillimeter arrays into space. The mission, closely aligned with the science priorities of the Japanese VLBI community, involves an active engagement of this community in the development of the mission, resulting in the formation of the Black Hole Explorer Japan Consortium. Here we present the current Japanese vision for the mission, ranging from scientific objectives to instrumentation. The Consortium anticipates a wide range of scientific investigations, from diverse black hole physics and astrophysics studied through the primary VLBI mode, to the molecular universe explored via a potential single-dish observation mode in the previously unexplored 50-70 GHz band that would make BHEX the highest-sensitivity explorer ever of molecular oxygen. A potential major contribution for the onboard instrument involves supplying essential elements for its high-sensitivity dual-band receiving system, which includes a broadband 300 GHz SIS mixer and a space-certified multi-stage 4.5K cryocooler akin to those used in the Hitomi and XRISM satellites by the Japan Aerospace Exploration Agency. Additionally, the Consortium explores enhancing and supporting BHEX operations through the use of millimeter/submillimeter facilities developed by the National Astronomical Observatory of Japan, coupled with a network of laser communication stations operated by the National Institute of Information and Communication Technology.

The Black Hole Explorer (BHEX) mission will enable the study of the fine photon ring structure, aiming to reveal the clear universal signatures of multiple photon orbits and true tests of general relativity, while also giving astronomers access to a much greater population of black hole shadows. Spacecraft orbits can sample interferometric Fourier spacings that are inaccessible from the ground, providing unparalleled angular resolution for the most detailed spatial studies of accretion and photon orbits and better time resolution. The BHEX mission concept provides space Very Long Baseline Interferometry (VLBI) at submillimeter wavelengths measurements to study black holes in coordination with the Event Horizon Telescope and other radio telescopes. This report presents the BHEX engineering goals, objectives and TRL analysis for a selection of the BHEX subsystems. This work aims to lay some of the groundwork for a near-term Explorers class mission proposal.

The Black Hole Explorer (BHEX) is a space very-long-baseline interferometry (VLBI) mission concept that is currently under development. BHEX will study supermassive black holes at unprecedented resolution, isolating the signature of the “photon ring” — light that has orbited the black hole before escaping — to probe physics at the edge of the observable universe. It will also measure black hole spins, study the energy extraction and acceleration mechanisms for black hole jets, and characterize the black hole mass distribution. BHEX achieves high angular resolution by joining with ground-based millimeter-wavelength VLBI arrays, extending the size, and therefore improving the angular resolution of the earthbound telescopes. Here we discuss the science instrument concept for BHEX. The science instrument for BHEX is a dual-band, coherent receiver system for 80-320 GHz, coupled to a 3.5-meter antenna. BHEX receiver front end will observe simultaneously with dual polarizations in two bands, one sampling 80-106 GHz and one sampling 240-320 GHz. An ultra-stable quartz oscillator provides the master frequency reference and ensures coherence for tens of seconds. To achieve the required sensitivity, the front end will instantaneously receive 32 GHz of frequency bandwidth, which will be digitized to 64 Gbits/sec of incompressible raw data. These data will be buffered and transmitted to the ground via laser data link, for correlation with data recorded simultaneously at radio telescopes on the ground. We describe the challenges associated with the instrument concept and the solutions that have been incorporated into the baseline design.

The Near-Earth Object Mission in the Infra-Red (NEOMIR) is the first ESA’s space-based mission fully dedicated to discovering near-Earth objects (NEOs), with a focus to detect and raise early warning for the smaller objects that are coming from the Sun direction, thus nearly impossible to be detected by ground-based optical survey. NEOMIR is currently in the early phases of mission study (phase A), with a potential launch date in the early 2030s.

The COronal Diagnostic EXperiment (CODEX) is a Heliophysics mission to measure the density, temperature, and velocity of the electrons in the solar corona with the primary goal of improving our understanding of the physical conditions of the solar wind in the acceleration region. The temperature and velocity measurement requires much higher signal-to-noise ratio than the density measurements. In solar coronagraphs, the diffraction of the solar disk light due to the occulting element is the dominant source of noise. Therefore, to further suppress the diffracted sun light with respect to the existing coronagraphs is a critical element of the CODEX design. To minimize the stray light due to diffraction, the selected optical design is a two-stage standard coronagraph with an external occulter, an internal occulter, and a Lyot stop. What is unique for this design is that a focal mask was inserted at the telescope focal plane. It works together with the field lens suppressing the stray light down by ~ another order of magnitude as compared to a traditional three-stage approach. During the optical design, a Fourier Transform based beam propagation software, i.e., GLAD, was used to model the beam path through the full coronagraph, from the external occulter to the detector array. All diffraction sensitive elements: external occulter, internal occulter, focal mask, and Lyot stop were carefully modeled and optimized. As a result, the requirement of achieving a stray light level which is one order of magnitude lower than F-corona was satisfied. On the other hand, to achieve the final suppression, a precision optical alignment is another must. This paper also presents our creative alignment procedure: using the combination of metrology, precision alignment equipment, and real time diffraction ring monitoring to minimize the diffraction. The final test results show that the suppression ratio (B/B0) reaches 10-11 level, which is equivalent to one order of magnitude lower than F-corona.

Understanding the origin of the Martian moons is the main objective of the JAXA MMX (Martian Moons eXploration) mission, that will be launched in October 2026. Among the 13 instruments composing the payload, MIRS is an infrared imaging spectrometer that will map the mineralogy and search for organic compounds on the moons’ surfaces. MIRS will also study the Martian atmosphere, focusing on the spatial and temporal variations of water, dust and clouds. MIRS is operating in the 0.9-3.6 μm spectral range with a spectral resolution varying from 22 nm to 32 nm. The field of view covers 3.3° whereas the instantaneous field of view is 0.35 mrad. This presentation will detail the design and present the end-to-end performance obtained during the final instrument test in a representative thermal environment.

The Lunar Thermal Mapper (LTM) is a compact multi-band push-broom infrared radiometer on the NASA Lunar Trailblazer mission due to launch in 2024. The LTM optics consists of a fast (F1.5) 5-mirror diamond turned free-form system. The mirrors are machined from lightweighted aluminium blanks with integral mounting flexures. The system is assembled on an athermal aluminium optical bench to maintain alignment through the launch and under the challenging thermal environment of lunar orbit. With this novel optical system LTM achieves high resolution infrared imagery in a compact, low mass instrument. We present the design and model performance of the optics, details of the optomechanical design and manufacture, and results from AIT of an optical breadboard and LTM flight model instrument. As the LTM optical system is seeing reuse for future missions (such as MIRMIS on ESAs Comet Interceptor) we discuss the use of the LTM optical design with higher resolution detectors.

Aim to Japan's participation in the Artemis program in the 2030s in mind, we pursue the feasibility studies of lunar telescope, including astronomical observations. Focusing on the meter-wavelength observations (observing frequency of lower than 50MHz), which cannot be observed in the harsh environments on the ground from the Earth, including the ionosphere and radio frequency interference, we have reported on conceptual design based on the results of our feasibility studies in Japan. The main scientific objectives we have studied so far are broadly covering the following three areas: astronomy and astrophysics, planetary science, and lunar science. In astrophysics, the observing frequency range of 1- 50MHz gives us an opportunity to observe the 21 cm global signal (spatial average temperature) from the Dark Ages, which is determined purely by cosmology and is not affected by first-generation star formation and cosmic reionization. In astronomy, it provides the images of the Milky Way galaxy at meter wavelengths. In planetary science, it will be possible to study the environments of exoplanets through 1) radio waves from auroras on gas giant exoplanets like Jupiter and 2) stellar radio-wave bursts. In lunar science, it has the potential to observationally study the lunar ionosphere, subsurface structure, and dust environment. At present, we plan the meter-wavelength interferometric array as lunar telescope, including the single-dish observations. In this paper, focused on the scientific requirements from cosmology, we will report the design concepts of Japanese lunar telescope project, including the advanced feasibility studies of antenna, receiver, signal chain and spectrometer that are compared as other studies in US, China and Europe. We named this project TSUKUYOMI.

The Dark Ages Explorer (DEX) is the European initiative for a radio interferometry facility on the lunar far side. DEX will focus on performing neutral hydrogen cosmology observations, aiming to obtain the spatial power spectrum of density fluctuations throughout the history of the early Universe. DEX is planned to consist of a large number (≥1024) of planar antenna elements deployed onto the lunar surface around the landing site, providing a densely filled aperture. The antenna elements are arranged in a regular grid, making it possible to generate sky snapshots by using the efficiency of a spatial 2D Fourier transform for every frequency bin. This talk introduces the concept design of DEX, shows the expected performance of the array in the presence of lunar regolith and discusses current and future efforts in technology development that are required to realise this design.

MoonLITE (Lunar InTerferometry Explorer) is an Astrophysics Pioneers proposal to develop, build, fly, and operate the first separated-aperture optical interferometer in space, delivering sub-milliarcsecond science results. MoonLITE will leverage the Pioneers opportunity for utilizing NASA’s Commercial Lunar Payload Services (CLPS) to deliver an optical interferometer to the lunar surface, enabling unprecedented discovery power by combining high spatial resolution from optical interferometry with deep sensitivity from the stability of the lunar surface. Following landing, the CLPS-provided rover will deploy the pre-loaded MoonLITE outboard optical telescope 100 meters from the lander’s inboard telescope, establishing a two-element interferometric observatory with a single deployment. MoonLITE will observe targets as faint as 17th magnitude in the visible, exceeding ground-based interferometric sensitivity by many magnitudes, and surpassing space-based optical systems resolution by a factor of 50×. The capabilities of MoonLITE open a unique discovery space that includes direct size measurements of the smallest, coolest stars and substellar brown dwarfs; searches for close-in stellar companions orbiting exoplanet-hosting stars that could confound our understanding and characterization of the frequency of Earth-like planets; direct size measurements of young stellar objects and characterization of the terrestrial planet-forming regions of these young stars; measurements of the inner regions and binary fraction of active galactic nuclei; and a probe of the very nature of spacetime foam itself. A portion of the observing time will also be made available to the broader community via a guest observer program. MoonLITE takes advantage of the CLPS opportunity to place an interferometer in space on a stable platform – the lunar surface – and delivers an unprecedented combination of sensitivity and angular resolution at the remarkably affordable cost point of Pioneers.

LuSEE Night is a low frequency radio astronomy experiment that will be delivered to the farside of the Moon by the NASA Commercial Lunar Payload Services (CLPS) program in early 2026. LuSEE Night is designed to characterize the galactic radio foreground with best-yet sensitivity and depth but will also measure solar, planetary, and other astrophysical sources. The payload system under contract and being developed jointly by NASA and the US Department of Energy (DOE) and consists of a 4 channel, 50 MHz Nyquist baseband receiver system and 2 orthogonal ~6m tip-to-tip electric dipole antennas. LuSEE Night will enjoy standalone operations through the lunar night, without the electromagnetic interference (EMI) of an operating lander system and antipodal to our noisy home planet. LuSEE Night will also be supported by a NASA-funded far-field calibration source, in the form of a lunar-orbiting radio transmitter that broadcasts a pseudo-random code sequence; LuSEE Night will correlate against the code and use the signal to calibrate antenna pattern and system spectral chromaticity.

The Pandora NASA Astrophysics Pioneers SmallSat mission employs a dual-channel observational approach, simultaneously utilizing visible photometry and infrared spectroscopy to assess stellar contamination of exoplanet transmission spectra. For the near-infrared spectroscopy Pandora will use a 2.5-micron cutoff Teledyne H2RG detector. The engineering design unit has undergone thermal-vacuum testing at Lawrence Livermore National Labs to characterize its performance under flight-like conditions. This paper provides an overview of testing conducted to date, shedding light on critical detector properties derived from subsequent analyses. Key parameters include read noise, gain, and saturation, offering insights into the detector’s capabilities and paving the way for enhanced data interpretation in the pursuit of unraveling the complexities within exoplanetary atmospheres.

CubeSpec is an ESA in-orbit-demonstration mission, based on a 12U CubeSat, targeting high-resolution optical astronomical spectroscopy of bright targets. It is developed and funded in Belgium and scheduled for launch early 2026. The CubeSpec payload consists of an off-axis Cassegrain telescope with a rectangular aperture filling the surface area of two CubeSat units, followed by a prism cross-dispersed echelle spectrograph folded behind the primary mirror of the telescope. The complete optical payload fits in approximately 6 units (∼12 x 20 x 30 cm) of the spacecraft. CubeSpec delivers a spectral resolution of R = 55 000 and covers the wavelength range from 420 to 620 nm. The optical design is sufficiently flexible to allow tuning it with minimum hardware changes to a wide range of spectral resolution and coverage. A fine-guidance system consisting of a piezo-actuated fine steering mirror and a fine-guidance sensor provide arcsec-precise centering of the source image on the slit of the spectrograph, cancelling out pointing errors and spacecraft jitter. In this contribution, we describe the optical and optomechanical design of the CubeSpec payload, and discuss the challenged imposed by the extremely compact size and the large temperature excursions endured during each orbit.

KU Leuven’s CubeSpec mission is pioneering the use of a CubeSat platform for advanced space-based spectroscopy.1 This innovation is partly due to its payload electronics, which must be space-efficient and powerconscious. To achieve exceptional pointing accuracy, CubeSpec employs a High-Pointing Precision Platform (HPPP) that works in tandem with the onboard Attitude Determination and Control System (ADCS). The HPPP utilizes a Fine Steering Mirror (FSM), controlled by piezo actuators, to direct light precisely onto the spectrograph slit. The design incorporates a DC-DC boost converter and a linear amplifier to meet the highvoltage demands of the piezo actuators. The HPPP setup is controlled in a closed-loop system with a Fine Guidance Sensor (FGS), a CMOS detector, and strain gauges that provide real-time feedback. The spectrograph output is captured by the Science Detector, which is the same detector model as the FGS. Due to stringent time requirements, a Xilinx Zynq 7000 FPGA manages the detector readout. The payload processor can communicate with the OBC over a CAN bus employing the CubeSat Space Protocol. This paper outlines the current progression in the development of CubeSpec’s payload electronics.

A-DOT (Active Deployable Optical Telescope) is a payload prototype of a 6U deployable telescope operating in the visible from 400 to 800 nm with an aperture diameter of 300 mm. It aims to deliver diffraction-limited performance using on-board wavefront sensing (WFS) and active control (WFC). A-DOT is currently in the design phase. This paper presents the development of a deployable, single-segment, mechanical prototype. The deployable mirror segment is kinematically mounted to a monolithic flexure using three spherical contacts in a cup-grooveflat arrangement. Tip, tilt and piston (PTT) are controlled using linear, piezoelectric actuators at each contact and the mirror position measured using capacitive sensors. The prototype is packaged within the allowable CubeSat volume and uses space-compatible hardware in a non-magnetic design.

In the search for life in our galaxy, and for understanding the origins of our solar system, the direct imaging and characterization of Earth-like exoplanets is key. In a step towards achieving these goals, the Superluminous Tomographic Atmospheric Reconstruction with Laser-beacons for Imaging Terrestrial Exoplanets (STARLITE) mission uses five CubeSats in a highly elliptical orbit as artificial guide stars to enable tomographic reconstruction of the atmosphere for extreme multi-conjugate adaptive optics (MCAO). Through the use of current and next-generation extremely-large ground-based telescopes, the STARLITE constellation at its ∼350,000 km apogee can provide brighter than -10 magnitude artificial guide stars from a 10 cm launching telescope in a sub-arcminute field of view for up to an hour. Careful selection and design of the ∼760 nm on-board laser will allow O₂ detection and characterization of exoplanet atmospheres. At a size of 12U, each satellite weighs only 19 kg and utilizes mostly commercially available off-the-shelf components to keep costs per satellite around $2M. In this paper, we will present the satellite mission concept and early system design for the STARLITE constellation.

The liquid crystal tunable filter (LCTF) is an optical bandpass filter whose transmitted wavelength can be electronically controlled. The device consists of several layers of the basic elements of polarizer - birefringent crystal (liquid crystal cells and/or quartz) - polarizer, i.e., a Lyot-filter. By changing the voltage applied to the liquid crystal (LC) cell, the phase difference of light in each layer can be controlled. Due to its multi-layer composition, the LCTF can transmit only light of any specific wavelength. The peak transmittance of the LCTF we developed is approximately 20–40%, with a band width (FWHM; full-width at half maximum) of 10–100 nm, depending on the wavelength. The device has no mechanical moving parts, is compact (37×37×<30 mm3 ), lightweight (<100 g), exhibits low power consumption, and can be utilized in a wide temperature range of 0 to 45 ◦C. Consequently, it is well-suited for multi-spectral or hyper-spectral imaging mounted on small satellites. In order to achieve high-precision observations in the space environment, we have implemented some technical improvements: (1) development of the liquid crystal (LC) cells, (2) endurance tests on LC cells under high temperature and high humidity conditions, (3) development of technology to stack LC cells, polarizers, and birefringent crystal plates in parallel using optical adhesive, (4) establishment of a calibration method that can correct the temperature dependence of the birefringence of liquid crystal and quartz, (5) development of a compact driver to control LCTFs using only electronic components that can be used in the space environment, (6) improvement of the switching speed of LCTF transmission wavelength, and (7) conducting radiation tests. Consequently, we have experience in conducting observations on orbit by five small satellites equipped with our LCTFs. Furthermore, we also present our patent for an optical arrangement to bring out the performance of LCTFs.

During the last few years, one of our main research topics has been developing a new type of spectropolarimeter intended for space applications. Initially analyzed numerically, the instrument has a compact, stable design without rotating components. The entire Stokes vector can be determined in a single shot in a vast spectral range. The simulations proved that the modulation schemes that can be obtained for this instrument are close to the optimal form. The objective of the current research is the experimental validation of this instrument. Here, we present the first results for determining the instrumental matrix and the demodulation results for a series of polarization states. In conclusion, we present the possible further developments of that project.

We have developed a compact broadband infrared imaging Fourier transform spectrometer, referred to as the 2D FTIR, employing common path wavefront division phase-shift interferometry. The system comprises a 3-reflector point-topoint optical setup with overlapping paths, incorporating two free-form mirrors and a pair of 20 mm high and 40 mm wide planar mirrors. Initially, we establish a one-dimensional multi-slit object plane with spacing tailored to match the FPA detector pixel size, effectively preventing destructive interference. Through precise optimization of the parameters of the two free-form mirrors (Mirror 1: 4th-order Zernike polynomial; Mirror 2: 6th-order Zernike polynomial), we achieve precise beam collimation, reflection through a phase shifter, and subsequent refocusing onto the FPA detector. Utilizing a commercial uncooled bolometer camera with a resolution of 640x480 pixels and a pixel size of 17μm, we attain optimal performance across the 4-20μm wavelength range, coupled with a generous 6mm diameter field of view. The spectrometer boasts a remarkable wavenumber resolution of 2.7 cm^-1, with R (λ=4μm) ≈ 1000, alongside a spatial resolution of 34μm. All components seamlessly fit within a 170x150x80 mm vacuum frame. The 2D FT-IR enables the acquisition of spectral maps post-image capture and offers a broad measurement wavelength range of 4-20 μm. After completion of development, we plan to employ it to study the generation mechanisms of cryogenically frozen organic matter simulating Titan's haze and to measure the low-temperature continuous spectral transmittance and refractive index of the GREX-PLUS spectroscopic components. Additionally, due to its high vibration resistance and compact design, we intend to deploy it as a spectrometer for compact satellites developed by JAXA. Lastly, it will serve as a pivotal test instrument for the PLANETS telescope, facilitating the evaluation of the telescope's resistance to atmospheric disturbances.

We present the concept for STARI: STarlight Acquisition and Reflection toward Interferometry. If launched, STARI will be the first mission to control a 3-D CubeSat formation to the few mm-level, reflect starlight over 10s to 100s of meters from one spacecraft to another, control tip-tilt with sub-arcsecond stability, and validate endto-end performance by injecting light into a single-mode fiber. While STARI is not an interferometer, the mission will advance the Technology Readiness Levels of the essential subsystems needed for a space interferometer in the near future.

RAFTER (Ring Astrometric Field Telescope for Exo-planets and Relativity) is a TMA telescope concept aimed at astrometric missions, and providing a wide FOV and high optical response uniformity over an annular region around the optical axis. This paper describes and analyzes the process of miniaturization and implementation of this idea into a Cubesat for technology demonstration purposes, and to evaluate its feasibility by analysing the performance and challenging aspects of different designs, calculating their mechanical tolerances and thermal sensitivity. We outline the critical aspects of the payload that can be tested and optimized in the framework of a dedicated CubeSat mission, in order to demonstrate the enabling technological contributors crucial to the development of a future larger scale mission.

The Visible Extragalactic background RadiaTion Exploration by CubeSat (VERTECS) is designed for observing Extragalactic Background Light(EBL). VERTECS mission requires attitude control stability better than 10 arcsec (1σ) per minute, pointing accuracy better than 0.1 deg, and the slew rate faster than 1 deg per sec. We discuss the software-in-the-loop (SIL) attitude simulator simulation to verify whether the current Attitude Determination Control System (ADCS) design and the planned orbit can meet the requirements for EBL observations. We simulate the attitude control system with the simulation software, taking into account the attitude control commands, the parameters of the ADCS hardware, and the expected attitude disturbances in the assumed orbit. This simulation shows the sequence of attitude maneuvers needed to meet the requirement. The simulation results indicate that the current observation sequence is feasible.

The extragalactic background light (EBL) is the integrated emission from out of our Galaxy.Its observation is crucial for revealing the history of star-formation from the early universe to the present epoch. Visible Extragalactic background RadiaTion Exploration by CubeSat (VERTECS) is a 6U astronomical satellite to observe the EBL in visible wavelength from 0.4 µm to 0.8 µm. To observe the EBL, a telescope with 11 lenses and a high-performance CMOS sensor are equipped within 3U volume. The remaining 3U comprises the bus section mainly based on the bus design previously developed at Kyushu Institute of Technology. This paper describes the design and verification processes of the structure and thermal model of the satellite to fulfill the interface and mission requirements. From a mission perspective, the precise attitude and orbit control system unit is mounted on the same interface plate as the telescope to meet stringent pointing stability requirements during observations. The purpose of the stiff design of this interface plate is to minimize structural deformation. Furthermore, integrating multiple external antennas with relatively large X-band and S-band communication units require effective routing harness management. Static stress analysis is performed under the quasistatic loading condition. In addition, modal analysis is also conducted to fulfill the strength and stiffness requirements of the launcher. A series of mechanical environmental tests (shock, random, and sinusoidal vibrations) have been conducted to verify the design and analysis results. The results showed that designed model can fundamentally withstand the launch environment.

Extragalactic Background Light (EBL), the cumulative light from outside the galaxy, is a crucial observational target for understanding the history of the universe. We are developing a CubeSat; VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat) with a 6U size (approximately 10 × 20 × 30 cm), equipped with Solar Array Wings (SAW). Our mission is to conduct extensive observations of the visible EBL. The satellite is designed to operate in a sun-synchronous orbit at an altitude of 500-680 km (approximately 15 orbits per day) and observe the EBL on the shadow side to avoid stray light from the Sun and Earth. To observe EBL, a high-performance CMOS sensor, attitude control devices, and high-speed communication equipment X-band are essential. We should note that these components these components consume a significant amount of power. Therefore, some strategic operational plans are necessary to operate this CubeSat within the limited power resources. In addition, VERTECS needs to meet its mission requirements, conducting 10 observations, 4 data downlinks, and 1 command uplink within a day. We have constructed some operational scenarios utilizing attitude control and SAW to meet these requirements, and we also constructed a power budget simulation for VERTECS. In this presentation, we describe how we plan to operate VERTECS utilizing the subsystems and the results of the power simulation during the operation.

The CEntral (field) Three-mirror Anastigmat (CETA) telescope is designed on the specifications of the proposed Theia mission, aiming at high precision differential astrometry over a large field, for exo-planetary system characterization and dark matter /dark energy search through the dynamics of star clusters. Usually, Three Mirror Anastigmat designs are either off-axis in terms of field, or decentered in terms of pupil. We propose a family of solutions using fully centred optics and a large on-axis field, at the expense of a non negligible central obscuration. We analyse in particular a 1 m class compact telescope, with 15 m effective focal length, i.e. suited to small pixel (4-6 $micro$m) CMOS detectors operating in the visible and near IR. Due to the underlying symmetry, the resulting optical response is quite good over a 14 arcmin radius field, and it is of special interest to astrometry applications. Also, manufacturing, alignment and calibration can be expected to benefit significantly; some basic aspects are preliminarily considered.

JASMINE is a Japanese near-infrared space mission with the scientific objectives of ultra-high-precision astrometric observations of stars in the central region of the Galaxy and exploration of terrestrial exoplanets around M-type stars. To achieve these scientific objectives, we are developing a 36-cm aperture diffraction-limited telescope with an emphasis on ultra-low stable telescope structure. The telescope will be equipped with an infrared detector and a bandpass filter for the wavelength range of 1000-1600 nm. For the astrometry, the telescope will have a high optical performance: the Strehl ratio larger than 0.9 at near-infrared wavelengths and is required to have a stable image distortion of less than a few tens micro arcsec during a low Earth sun-synchronous orbital motion. The telescope has an axisymmetric Korsch-type optical system which is easy to be designed to have the high optical performance over a large field-of-view. We present the progress of the telescope optics design, optics alignment/adjustment procedures, and telescope optics evaluation and verification procedures.

Structural, Thermal and Optical Performance (STOP) analysis is performed to investigate the stability of the telescope to be onboard the Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE). In order to perform one of the prime science objectives, high-precision astrometric observations in the wavelength range of 1.0–1.6 µm toward the Galactic center to reveal its central core structure and formation history, the JASMINE telescope is requested to be highly stable with an orbital change in the image distortion pattern being less than a few 10 µas after low-order correction. The JASMINE telescope tried to satisfy this requirement by adopting two design concepts. Firstly, the mirror and their support structures are made of extremely low coefficientof-thermal-expansion materials. Secondly, their temperatures are highly stabilized with an orbital variation of less the 0.1 ◦C by the unique thermal control idea. Through the preliminary STOP analysis, the structural and thermal structural feasibility of the JASMINE telescope is considered. By combining the results of the structural and thermal design, its thermal deformation is estimated. The optical performance of the JASMINE telescope after the thermal deformation is numerically evaluated. It is found that the thermal displacement of the mirrors in the current structural thermal design produces a slightly large focus-length change. As far as the focus adjustment is adequately applied, the orbital variation of the image distortion pattern is suggested to become acceptable after the low-order correction.

This paper covers BAE/Ball’s 4 K Cryocooler, which is comprised of TRL 6-9 subassemblies and meets the needs of multiple future space missions. The 4 K Cryocooler is comprised of a hybrid Stirling Pre-Cooler and a J-T (Joule-Thomson) Cryocooler driven by the MACCE (Modular Advanced Cryocooler Control Electronics). The Stirling Pre-Cooler uses the BAE/Ball 2-stage SC-235C 2-stage cryocooler which has flown on the TIRS-1 and TIRS -2 NASA missions. The precooler provides cooling at 15-18 K to precool the J-T Cooler and around 65 K to intercept thermal system heat loads. The J-T Cryocooler uses the TRL 9 flight SC-235/TIRS compressor with reed valves with a J-T cold head (heat exchangers, plumbing, J-T valve, etc.) from the ACTDP TRL 6 Engineering unit that demonstrated cooling to 3.4 K. The MACCE electronics are TRL 8 and have been delivered for flight.

We have developed a robust bandpass filter that is suitable for use in mid- and far-infrared cryogenic space telescopes using simple photolithography. The filter consists of Babinet complementary metamaterial mirrors, which are sub-wavelength holes on a silicon wafer with metalized rim and bottom, and non-metalized side wall. The mirrors work as a “Fabry-Perot interference” type bandpass filter and have a spectral resolving power of R~10. The central wavelength is tunable by adjusting the optical distance between the surface and the bottom. It has higher mechanical toughness compared to conventional metal mesh-filters because of the support of the silicon wafer. It also has higher resistance to thermal cycles compared to conventional multi-layer filters because of its simple structure. The central wavelength can be configured only by the sub-wavelength structure without changing the depth of the holes, so that monolithic filters with different central wavelengths at each position can be fabricated.

In the 1990s COBE/FIRAS showed that the CMB spectral energy distribution is close to a perfect blackbody with tiny departures, ΔI/I ≃ 10⁻⁵, referred to as spectral distortions, that encode information about the full thermal history of the Universe. High-precision spectroscopy of the CMB is one of the three themes identified by the ESA Voyage 2050 programme to explore the early Universe. The BISOU (Balloon Interferometer for Spectral Observations of the primordial Universe) project is a pathfinder of a future space mission dedicated to the absolute measurement of the CMB spectrum. With the instrument and sky models developed in [6], we examine the influence feasibility of detecting the y-distortion monopole (probing the hot gas in the Universe).

The Probe far-Infrared Mission for Astrophysics (PRIMA) contains two instruments: an imager (PRIMAGER) and a multi-band spectrometer (FIRESS). These two instruments require detector cooling to 100 mK and require parts of the optical train to operate at 1.0 K. From a base temperature of 4.5 K, provided by a JWST-like cryocooler, a 5-stage Continuous Adiabatic Demagnetization Refrigerator (CADR) will provide this cooling to both instruments. The PRIMA CADR is based on heritage parts from the Hitomi and the X-Ray Imaging and Spectroscopy Mission (XRISM) ADRs and from recent Strategic Astrophysics Technology (SAT)-developed hardware. The CADR will provide 700 microW of lift at 1.0 K and 9 microW of lift at 100 mK to meet the two instruments (PRIMAGER and FIRESS) cooling requirements with a factor of 2 margin. The CADR is designed to reject a maximum of 8 mW at the 4.5 K cryocooler heat sink. This paper will describe the CADR, its requirements, its operation, and its heritage.

PRIMA is a cryogenically-cooled, far-infrared observatory for the community for the beginning of the next decade (∼2031). It features two instruments, PRIMAger and FIRESS. The PRIMAger instrument will cover the mid-IR to far-IR wavelengths, from about 25 to 260 µm. Hyperspectral imaging can be obtained in 12 medium-resolution bands (R ∼ 10, more precisely a linear variable filter) covering the wavelength range from 25 to 80 micrometers, and broad-band (R ∼ 4) photometric and polarimetric imaging can be carried out in four bands between 80 and 260 µm. PRIMAger’s unique and unprecedented scientific capabilities will enable study, both in PI and GO programs, of black hole and star-formation coevolution in galaxies, the evolution of small dust grains over a wide range of redshift, and the effects of interstellar magnetic fields in various environments, as well as opening up a vast discovery space with its versatile imaging and polarimetric capabilities. One of the most ambitious possibilities is to carry out an all-sky far-IR survey with PRIMAger, creating a rich data set for many investigations. The design of PRIMAger is presented is an accompanying paper (Ciesla et al., SPIE Astronomical Telescopes + Instrumentation 2024).

We describe the space observatory architecture and mission design of the Single Aperture Large Telescope for Universe Studies (SALTUS) mission, a NASA Astrophysics Probe Explorer concept. SALTUS will address key far-infrared science using a 14-m diameter <45 K primary reflector (M1) and will provide unprecedented levels of spectral sensitivity for planet, solar system, and galactic evolution studies, and cosmic origins. Drawing from Northrop Grumman's extensive NASA mission heritage, the observatory flight system is based on the LEOStar-3 spacecraft platform to carry the SALTUS Payload. The 14-m M1 is an off-axis inflatable membrane radiatively cooled by a two-layer sunshield. The SALTUS 5-year mission lifetime is driven by a two-consumable architecture: the propellant system and the inflation control system. The Core Interface Module, a multi-faceted composite truss structure, provides a load path with high stiffness, mechanical attachment, and thermal separation between the Payload and spacecraft. The spacecraft maintains an attitude off M1's boresight with respect to the Sun line to facilitate the <45 K thermal environment. SALTUS will reside in a Sun-Earth halo L2 orbit. The instantaneous field of regard provides two continuous 20° viewing zones around the ecliptic poles resulting in full sky coverage in six months.

Theoretical calculations predict that high-resolution spectroscopy of H₂O gas lines in the mid-infrared region is the most promising method to observationally identify the snow-line, which has been proposed as the critical factor separating gas giants from solid planets in the planetary formation process. This requires the spectroscopic observations from space with R = λ/Δλ ≥ 30, 000. For this purpose, we propose a mid-infrared (10-18 μm) high-resolution spectrometer to be onboard the GREX-PLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer) mission. We are developing "immersion grating” spectroscopy technology for high-resolution spectroscopy in space. We have chosen CdZnTe as a candidate for the optical material. We report the current status of the development of the CdZnTe immersion grating, including evaluation of its optical properties (absorption coefficient and refractive index) at cryogenic temperatures, development of an anti-reflection coating with a moth-eye structure for wide-wavelength coverage, and verification of machinability for grating production. We plan to make a prototype spectrometer to demonstrate the capability of the immersion grating with ground-based observations in the N-band (λ = 8–13 μm) and beyond.

We are developing an Immersion Grating (IG) made of CdZnTe which is designed for a high-dispersion midinfrared spectrograph (10-18 μm, R = λ/Δλ ∼ 30, 000) to be onboard the next-generation infrared space telescope GREXPLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer). The adoption of an IG will reduce the spectrometer size to 1/n in length (1/n³ in volume, n: refractive index) compared to conventional diffraction gratings. In order to determine the absorption coefficient of the high-resistivity CdZnTe, we developed a new measurement system for transmittance in 10-18 μm with cryogenic common-path double beam optics equipped with filament lamp source inside the vacuum chamber, which enables accurate determination of the transmittance at the cryogenic temperature by considering the effect of the multiple Fresnel reflection at the sample surface. By the new transmittance measurement system, the CdZnTe sample can be cooled down to ~6 K by employing cooled long wavelength band pass filter (λ > 7 μm) to attenuate the peak emission of the filament lamp (λ ~ 2 μm). In the present paper, we report the results of transmittance measurement with high precision (δτ~0.03%) by our new equipment for the high-resistivity CdZnTe, and the absorption coefficient α of high-resistivity CdZnTe. By applying the value of refractive index n at T > 5.7 K reported recently, α was estimated to be 0.00225 cm-1 and 0.00036 cm^-1 at T~300 K and ~12 K, respectively at λ~10 μm in wavelength. In contrast to low-resistivity CdZnTe, the obtained values for α of high-resistivity CdZnTe have shown only slight temperature dependence, and the absorption coefficient values were smaller than the requirement: α<0.01 cm^-1 for the IG material. The high-resistivity CdZnTe was likely to be a candidate material of IG for GREX-PLUS high-resolution spectrograph..

We’re developing an immersion grating made of CdZnTe designed for a high-dispersion mid-infrared spectrograph (10-18 μm, R = λ/Δλ ∼ 30, 000) to be onboard the next-generation infrared space telescope GREX-PLUS. The adoption of an immersion grating will reduce the spectrometer size to 1/n (1/n³ in volume, n: refractive index) compared to conventional diffraction gratings. To determine this absorption coefficient accurately, we need to take the effect of multiple reflection into account that depend on the refractive index. However, the accurate refractive index of CdZnTe (Δn < 10⁻⁴) at 10-18 μm below 20 K has not been measured yet. Therefore, we’re developing a measurement system of the refractive index at cryogenic temperatures in the mid-infrared range. We adopt the minimum deviation method in this system to measure the refractive index, measuring the apex and deviation angle of the prismatic sample of material to be measured. Here we give an overview of the measurement system, as well as preliminary results of the refractive index measurement.

Euclid, the M2 mission of the ESA’s Cosmic Vision 2015-2025 program, aims to explore the Dark Universe by conducting a survey of approximately 14 000 deg² and creating a 3D map of the observable Universe of around 1.5 billion galaxies up to redshift z ∼ 2. This mission uses two main cosmological probes: weak gravitational lensing and galaxy clustering, leveraging the high-resolution imaging capabilities of the Visual Imaging (VIS) instrument and the photometric and spectroscopic measurements of the Near Infrared Spectrometer and Photometer (NISP) instrument. This paper details some of the activities performed during the commissioning phase of the NISP instrument, following the launch of Euclid on July 1, 2023. In particular, we focus on the calibration of the NISP detectors’ baseline and on the performance of a parameter provided by the onboard data processing (called NISP Quality Factor, QF) in detecting the variability of the flux of cosmic rays hitting the NISP detectors. The NISP focal plane hosts sixteen Teledyne HAWAII-2RG (H2RG) detectors. The calibration of these detectors includes the baseline optimization, which optimizes the dynamic range and stability of the signal acquisition. Additionally, this paper investigates the impact of Solar proton flux on the NISP QF, particularly during periods of high Solar activity. Applying a selection criterion on the QF (called NISP QF Proxy), the excess counts are used to monitor the amount of charged particles hitting the NISP detectors. A good correlation was found between the Solar proton flux component above 30 MeV and the NISP QF Proxy, revealing that NISP detectors are not subject to the lower energy components, which are absorbed by the shielding provided by the spacecraft.

Euclid is a European Space Agency (ESA) wide-field space mission dedicated to the high-precision study of dark energy and dark matter. In July 2023 a Space X Falcon 9 launch vehicle put the spacecraft in its target orbit, located 1.5 million kilometers away from Earth, for a nominal lifetime of 6.5 years. The survey will be realized through a wide field telescope and two instruments: a visible imager (VIS) and a Near Infrared Spectrometer and Photometer (NISP). NISP is a state-of-the-art instrument composed of many subsystems, including an optomechanical assembly, cryogenic mechanisms, and active thermal control. The Instrument Control Unit (ICU) is interfaced with the SpaceCraft and manages the commanding and housekeeping production while the high-performance Data Processing Unit manages more than 200 Gbit of compressed data acquired daily during the nominal survey. To achieve the demanding performance necessary to meet the mission’s scientific goals, NISP requires periodic in-flight calibrations, instrument parameters monitoring, and careful control of systematic effects. The high stability required implies that operations are coordinated and synchronized with high precision between the two instruments and the platform. Careful planning of commanding sequences, lookahead, and forecasting instrument monitoring is needed, with greater complexity than previous survey missions. Furthermore, NISP is operated in different environments and configurations during development, verification, commissioning, and nominal operations. This paper presents an overview of the NISP instrument operations at the beginning of routine observations. The necessary tools, workflows, and organizational structures are described. Finally, we show examples of how instrument monitoring was implemented in flight during the crucial commissioning phase, the effect of intense Solar activity on the transmission of onboard data, and how IOT successfully addressed this issue.

In this paper, we explore a way to extract the Zernike coefficients from low-resolution PSF images using a neural network model. The goal of this study is to obtain accurate reconstructions of instrumental responses even with under-sampled PSFs. We used the Python module POPPY to simulate a Newtonian telescope system with a primary mirror diameter of 1 meter and a secondary mirror diameter of 0.2 meter. PSFs were simulated over a wavelength range from 200 nm to 1000 nm. Detector sampling parameters included a pixel scale of 0.05 arcseconds/pixel and a 32x32 pixel grid. The ZerNet model was developed based on the Inception architecture. The input is a 32x32 pixel PSF image and the output is a set of Zernike coefficients. The model has three blocks of convolutional kernels of different sizes. These are combined and flattened, then pass through several layers of dense neurons before being activated by a hyperbolic tangent function to predict Zernike coefficients. The model was trained using the Adam optimizer with a learning rate of 0.001 over 40 epochs and a batch size of 64. The data was divided into three sets: training (70%), validation (20%), and test (10%). The ZerNet model showed good accuracy in predicting Zernike coefficients from PSF images. The accuracy improved with increasing wavelength, reaching 95.34% at 1000 nm. The PSF reconstruction error was measured using the Frobenius norm and showed a reduction in error with higher order Zernike coefficients. The model showed that the median error decreased with increasing order, proving that including higher order Zernike coefficients helps with PSF reconstruction.

Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy and dark matter. Scientific objectives demand a pointing stability of few tens of milliarcseconds (mas), which is achieved using a Fine Guidance Sensor (FGS) that provides high-precision pointing information as input to the spacecraft Attitude and Orbit Control Subsystem (AOCS). During the Performance Verification Phase, a reconstruction of instantaneous attitude at high precision has been achieved by using science instruments in special operating modes. The pointing jitter derived from these observations is correlated with the FGS/AOCS reported attitude to evaluate consistency. A precision of 2-3 mas is achieved in the reconstructed attitude at 30 ms time resolution in the optical channel, and 3 seconds in the infrared channel. The observation design, data analysis techniques and reconstructed attitude jitter curves are presented.

The Nancy Grace Roman Space Telescope project is NASA's next flagship astrophysics mission to study dark energy, dark matter, and exoplanets along with the innumerable topics that will be enabled by the infrared survey telescope's instruments. The Wide Field Instrument contains a focal plane of 18 newly developed Teledyne H4RG-10 HgCdTe detectors. Roman's focal plane completed its first system level thermal vacuum test at NASA Goddard in 2022, when an increase in dark current compared to component level testing was observed for several detectors. Roman chartered an anomaly review board (ARB) and in collaboration with Teledyne undertook a testing program to help identify possible root cause and select from Roman's spare inventory suitable replacement detectors for devices that had significantly degraded. A possible root cause was determined by the ARB along with recommendations for how to prevent further degradation. We summarize the initial observation of the detector anomaly, present the detector testing strategy to find suitable spares and provide evidence of root cause, share the general findings of the ARB, and show new data showing the improved dark current performance.

The SPHEREx satellite will survey the entire sky between 0.75 - 5.0 μm in over 100 wavelengths with spectral resolving power R = 35 to 130 to study cosmic inflation, the history of galaxy formation, and biogenic ices in the Milky Way. The instrument uses six HAWAII-2RG detectors and linear variable filters (LVF) that sort incoming photons into different wavelengths along one spatial direction of the detectors. To minimize the scattered light produced when sources outside of SPHEREx field of view land on the LVF mounting frame (also known as “dragon’s breath”), a scale model was tested to refine a double undercut edge design and coating recipe that halves the ghost size and reduces the ghost’ intensity by 10-fold. We present here the edge design, the scale model experiment, and the characterization of the ghost in the flight telescope.

The Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx) is an upcoming all-sky near-infrared spectroscopic survey satellite designed to address all three primary science goals of NASA’s Astrophysics Division. SPHEREx employs a series of Linear Variable Filters (LVFs) to create 102 spectral channels across the wavelength range of 0.75 to 5 µm, with spectral resolutions R between 35 and 120. This paper presents the spectral calibration setup used for SPHEREx and discusses the various challenges encountered during the measurement process. Ultimately, we demonstrate the spectral responses for all 25 million pixels in SPHEREx.

ARRAKIHS is an ESA mission dedicated to observing dwarf galaxies and stellar streams. Its objective will be to test the standard cosmological model, particularly regarding the nature of dark matter. It will use four telescopes operating in the visible and near infrared spectral ranges. As they will observe ultra-low brightness objects, an extreme level of stray light control is necessary. A large external baffle is necessary to prevent out-of-field light from entering the telescope, with an extreme stray light rejection down to 10-11. This paper will discuss the design of this baffle. We will present the design trade-offs, as different possible baffle architectures were considered. Ultimately, the selected architecture consists in developing one baffle for two telescopes, hence a total of two baffles are used on the payload. A multi-stage baffle is developed, in the heritage of the CoRoT baffle which is seen as one of the best ever designed. Moreover, we will discuss the reflections on the test setup which will be implemented for validating the design on a prototype.

We describe our technical approach to developing a space observatory to survey the large-scale distribution of neutral and ionized intergalactic gas during cosmological reionization (the landmark event of “Cosmic Dawn”) from 400 to 800 million years after the Big Bang. To look this far back in time at the large-scale distributions of ionized gases, we use wide-field, narrow-passband surveys for Lyman alpha light from individual galaxies red-shifted to the near-infrared. Wherever this light can be seen, it implies the presence of ionized gas. We are developing a large FOV (0.5-to-1.0-degree) instrument with plate scale on the order of 0.3”/pixel to obtain a comprehensive view of the reionization process over a representative volume of the early universe. To maximize science return, the Reionization Explorer (REX) will be placed in a high orbit. Through disciplined application of design-for-cost principles and a thorough searching for existing designs that can achieve our science objectives, we have developed what could be a game changing approach at advancing our understanding of the formation of the universe on a limited Small Explorer (SMEX) budget by leveraging existing telescope, instrument, and spacecraft designs.