The 2020 Astrophysics Decadal Survey (Astro2020) recommended NASA build a new fleet of future great observatories. The first mission will be an infrared-optical-ultraviolet (IR/O/UV) space telescope, now designated as the Habitable Worlds Observatory (HWO). HWO will directly image and characterize exoplanets and conduct a wide range of groundbreaking astrophysics observations in the ultraviolet-visible-near infrared wavelength range. Astro2020 also recommended a “Great Observatories Mission and Technology Maturation Program” as its highest priority in Enabling Programs for Space. Various coordinated activities have been spun up, and more are planned in the future. We will explore the principles, priorities, status, and next steps for HWO as part of GOMAP.

NASA’s Habitable Worlds Observatory (HWO) will consist of a segmented telescope and high contrast coronagraph to characterize exoplanets for habitability. Achieving this ambitious science goal requires an ultra-stable optical system with wavefront stability on the order of picometers in certain critical modes. This talk will describe the ongoing process to perform systems engineering, integrated modeling, and maturation of key technologies to achieve this level of performance, with a focus on the ultra-stable telescope.

The NASA/ESA Hubble Space Telescope provides us with many lessons regarding the interplay between science and technology that will be applicable to future telescopes. In this talk, we will consider several “case studies” where technological choices and advances had profound impacts on the science from HST and, conversely, where science needs drove technical and operational plans. HST is unique amongst astronomy space missions by virtue of its multiple upgrades during servicing missions. Furthermore, HST has been fortunate to have operated during a period of dramatic improvements in computational and communications capabilities which have changed how the scientific community interacts with both the observatory and its data. We will discuss how this has influenced both the evolution of astronomical research, the continuing development HST’s systems, and implications for future missions.

ZERODUR®’s thermal characteristics provide insight into realization of new domains of dimensional stability that are expected to be required for NASA’s Habitable Worlds Observatory (HWO). These attributes go far beyond the thermal trade space usually considered, namely low Coefficient of Thermal Expansion (CTE) and high transient resilience factor (Diffusivity/CTE). Response to thermal stimulus happens both at the segment scale, and at mid-spatial frequencies within the segment. Data resolved to these scales is crucial since perturbations at each of these scales will limit coronagraphic contrast. We will explore established studies on ZERODUR®, and what these suggest about the present state-of-the-art toward achieving HWO’s lofty requirements.

Despite thorough and careful surface cleaning, evaporated or sputtered metallic aluminum mirror coatings are well known to be plagued by a multitude of pinholes in the coatings. These pinholes contribute to light scattering and light reduction. Subsequent corrosion and penetration of contaminants in the pinholes and on the edges of the metal coating result in degradation and eventual coating destruction. At this point, mirrors are stripped, cleaned, and recoated with aluminum. In this work, we report the reduction of coating pinholes by up to a factor of 100x by utilizing First Contact Polymer Apply-Dry Peel technology as a final step in surface cleaning before coating. We fabricated an intensity-controlled imaging system to image backside illuminated optics and quantify the pinholes in aluminum mirror films. Imagej analysis of the size-calibrated pinhole distribution and light intensity resulted in statistical distributions plots of intensity vs pinhole size for each sample. Samples were prepared by stripping existing coatings with Green River mirror strip solution, followed by a standard cleaning procedure that consisted of a light NaOH wash, hand polishing with calcium carbonate slurry, alconox solution wash, distilled water(2X), and 200 proof ethanol wash (2x). After drying, one substrate was placed in the vacuum chamber and sputter coated with aluminum. The other sample was coated with Red First Contact Polymer Solution, allowed to dry, and the polymer film peeled of after pacing the substrate in the chamber for coating. Results show that the conventionally treated cleaned and dragwiped surfaces had 758 and 435 pinholes and the polymer strip coating cleaned surfaces had 38 and 9 pinholes. We believe that further studies and modified surface pretreatments can pave the way to reliably make zero defect coatings, not just for aluminum mirrors, but for all optical coatings.

Low cost, high performance lightweight Aluminum mirror provides an alternative to glass ceramic, ceramic, and exotic metal mirrors. NASA funded several lightweight Aluminum mirror technology development efforts for future space and balloon-borne infrared telescope programs. As part of these efforts, subscale Al-SiC metal matrix composite, Aluminum-6061 and Aluminum-5083 mirrors, and additive manufactured AlSi10Mg mirrors were evaluated at room temperature to 20 degrees Kelvin for its optical performance. This paper will discuss objectives, material properties, fabrication, cryogenic testing infrastructure and instrumentation, thermal test results, modelling effort compared to empirical data, and lessons learned.

We fabricated three freeform mirrors for the KASI-Deep Rolling Imaging Fast Telescope pathfinder, which is a confocal off-axis freeform three-mirror system with a 300 mm entrance pupil diameter. During the fabrication process, we light-weighted the primary mirror, reducing its weight by 52%. Front surfaces of these off-axis freeform mirrors were formed by a series of production process, including grinding, polishing, forming, and finishing. Measuring surface profile has been performed by using Coordinate Measuring Machines (CMMs) for the grinding process and an interferometer with Computer Generated Holograms (CGHs) for polishing, forming, and finishing process. The test results for all three mirrors were well within the required value of 20 nm RMS.

The warm-hot phase coronal gas, known as the circumgalactic matter (CGM), around galaxy halos plays a critical role in the evolution of galaxies. However, the morphology of the CGM is poorly understood as it is difficult to detect the extreme-UV (EUV) emission from this diffuse gas. Aspera, a small satellite telescope, is designed to map the EUV emission from the CGM of nearby galaxies. In order to achieve high observation efficiency, the payload has a unique dual-channel optical layout sharing a Microchannel plate (MCP) detector. The spectroscopy layout benchmarked the Rowland Circle ( OAP + slit + curved diffractive optics) and adopted a special coating to enhance reflectivity at EUV (~103.2 nm). The unique dual-channel layout requires co-pointing alignment of both channels and tight tolerance of each channel alignment. We reviewed the tolerance and sensitivity analyses of the optical system. The comprehensive Monte Carlo simulation provides the required alignment accuracy, and we proposed appropriate alignment plans using the interferometer and computer-generated hologram (CGH). The proposed alignment strategy is available for quantitative and decomposed evaluation of misalignin

Large Aperture Mirrors (LAMs) are critical elements of both space and ground-based telescopes. The need exists to characterize both the vibrational response and spatio-temporal modes of a membrane-based LAM’s structure. This data is essential to LAM’s design, configuration and performance when placed in the relevant space or ground operational environment. This presentation discusses the WF-LDV - a newly developed instrument capable of real-time evaluation of LAM’s vibrational spectra and spatial dynamics of its membrane-based mirror surface. WF-LDV allows real time sub-nanometer accuracy in measuring the displacement of the mirror over a multi-kHz frequency range. Our innovative WF-LDV design supports multiple modes of optical measurement tailored specifically for LAM design.

The Wide Field Instrument (WFI) aboard the Nancy Grace Roman Space Telescope covers 0.48 to 2.3 um wavelength. The instrument operates at cryogenic temperatures to limit the impact of thermal self-emission (TSE) and has a pupil mask located at the WFI entrance pupil to block thermal emissions from the warmer upstream telescope components. A novel mask alignment recovery test is presented that takes advantage of the fact that the exit pupil of the front-end optics is not well formed and produces sharp shadows of the pupil mask across the detector if illuminated from individual points in the telescope entrance pupil.

Progress in development of a multiple-order diffractive engineered (MODE) lens as applied to space telescopes, where an ultralightweight primary lens is used instead of a mirror, is presented. Precision glass molding is used to fabricate a prototype 0.24 m diameter primary lens, and advanced alignment technology is used to bond lens segments into a ridged, monolithic structure. The primary lens is used in an f/4.17 telescope with a color corrector that provides diffraction-limited imaging over the astronomical R-band of wavelengths (589 nm to 727 nm) and +/- 0.125° field of view. Fabrication data, alignment results, and imaging experiments are presented.

The detection and characterization of habitable worlds around other stars is one of the key science goals of future space observatories, a goal that will require high contrast imaging (HCI) instruments capable of starlight suppression to the 10^-10 level. The development of high-resolution, low-noise controllers for high actuator-count DMs will be crucial to achieving this contrast. We report the optical characterization of a MEMS Kilo-C deformable mirror from BMC driven by a custom controller, including the static and dynamic performance of the DM facesheet and the contrast achieved in vacuum with the DM integrated in a high contrast imaging testbed.

Characterizing Gravity-sag (G-sag) is an essential part of developing a large space-based optic. A method to back out gravity sag of a light-weighted optic using a CGH will be demonstrated. The results from the G-sag CGH determination is compared to the G-sag and Zero-G figure obtained during horizontal G-sag testing. The results from the CGH testing are also compared to the G-sag figure determined from modeling.

Increasing the demand for the surface quality of optics, such as high-power laser, space optics, and aerospace, the development of optical polishing and fabrication techniques have been investigated. Especially, high quality and ultra-precision optical surface are significantly required for shorter wavelength due to diffraction limit. Ion beam figuring (IBF) have been used a high-end method of correcting errors on an optical surface at atomic level by sputtering, which is suitable for last processing steps. Lately, we have successfully developed a gas cluster ion beam (GCIB) that is used as a sputtering or primary ion beam for time-of-flight secondary ion mass spectrometry (ToF-SIMS). Here, we applied GCIB to polish and fabricate for several optical substrates including UV and VUV mirrors. To demonstrate this technique, we considered the GCIB parameters such as beam diameter, irradiation time, incidence angle of GCIB, and gases driving the cluster ion source. During the experiments, we used an electron flood gun to compensate surface charging on the optics. We also measured roughness profiles and surface textures in terms of before and after polishing using coherence correlation interferometry (CCI). We will discuss development possibility of GCIB as a new technique of polishing and fabrication for optical substrates.

Todays high reliability devices require photonic and optical components to be free from contaminants prior to final integratiuon into moduals. This is especially true for high power lasers, camera modules, etc. Often times multiple cleaning steps are needed on the part in order to remove debris left behind from it's carrier. Gel-Pak has studied various material and formfactor combinations that could possibly eliminate the need for these costly cleaning and inspection steps. This poster will present findings regarding a carrier that avoids contact with the active areas of optics and photonic devices.

This study presents the steps of manufacturing of thin shell mirrors for adaptive optics. TNO, in cooperation with the University of Hawaii Institute for Astrophysics, UC Santa Cruz, Fraunhofer IPT, NOVA and Huygens Optics, have been developing adaptive secondary mirrors (ASM) for the UH 2.2 meter and NASA IRTF telescopes. The ASM shells are slumped convex aspheres, with a 620 and 243 mm diameter respectively. The thin shell mirrors have fast actuators mounted on the backside to correct the wavefront errors caused by atmospheric turbulence. The manufacturing of thin shell mirror is the highlighted part of complete manufacturing steps of ASM for this study. This part includes anti-sticking coating for slumping, slumping, shape correction with grinding/polishing/MRF, and coating of front and backside of the mirror, as well as metrology. The manufacturing of the thin shells is one of the critical technologies for deformable mirrors for adaptive optics.