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Continuous wavefront sensing benefits space observatories in on-orbit optical performance maintenance. To measure the phase of a wavefront, phase retrieval is an attractive technique as it uses multiple point spread function (PSF) images that are acquired by the telescope itself without extra metrology systems nor complicated calibration. The focus diverse phase retrieval utilizes PSFs from predetermined defocused positions to enhance the dynamic range of the algorithm. We describe an updated visible light active optics testbed with the addition of a linear motorized focus stage. The performance of the phase retrieval algorithm in broadband is tested under various cases. While broadband pass filters have advantages in higher signal-to-noise ratio (SNR), the performance of phase retrieval can be restricted due to blurred image caused by diffraction and increased computing cost. We used multiple bandpass filters (10 nm, 88 nm, and 150 nm) and investigated effects of bandwidth on the accuracy and required image acquisition conditions such as SNR, reaching accuracies below 20 nm RMS wavefront error at the widest bandwidth. We also investigated the dynamic range of the phase retrieval algorithm depending on the bandwidth and required amount of defocus to expand dynamic range. Finally, we simulated the continuous wavefront sensing and correction loop with a range of statistically generated representative telescope disturbance time series to test for edge cases.

When a telescope doesn't reach a reasonable point spread function on the detector or detectable wavefront quality after initial assembly, a coarse phase alignment on-sky is crucial. Before utilizing a closed loop adaptive optics system, the observatory needs a strategy to actively align the telescope sufficiently for fine wavefront sensing. This paper presents a method of early-stage alignment using a stochastic parallel-gradient-descent (SPGD) algorithm which performs random perturbations to the optics of a three mirror anastigmat telescope design. The SPGD algorithm will drive the telescope until the wavefront error is below the acceptable range of the fine adaptive optics system to hand the telescope over. The focused spot size over the field of view is adopted as a feed parameter to the SPGD algorithm and wavefront peak-to-valley error values are monitored to directly compare our mechanical capabilities to our alignment goal of diffraction limited imaging and fine wavefront sensing., Comment: 7 pages, 4 figures, presented at SPIE Optics + Photonics 2024

Aspera is a NASA Astrophysics Pioneers SmallSat mission designed to study diffuse OVI emission from the warm-hot phase gas in the halos of nearby galaxies. Its payload consists of two identical Rowland Circle-type long-slit spectrographs, sharing a single MicroChannel plate detector. Each spectrograph channel consists of an off-axis parabola primary mirror and a toroidal diffraction grating optimized for the 1013-1057 Angstroms bandpass. Despite the simple configuration, the optical alignment/integration process for Aspera is challenging due to tight optical alignment tolerances, driven by the compact form factor, and the contamination sensitivity of the Far-Ultraviolet optics and detectors. In this paper, we discuss implementing a novel multi-phase approach to meet these requirements using state-of-the-art optical metrology tools. For coarsely positioning the optics we use a blue-laser 3D scanner while the fine alignment is done with a Zygo interferometer and a custom computer-generated hologram. The detector focus requires iterative in-vacuum alignment using a Vacuum UV collimator. The alignment is done in a controlled cleanroom facility at the University of Arizona., Comment: Manuscript submitted for Proceedings of Astronomical Telescopes + Instrumentation 2024, Paper no. 13093-9

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 $3-10\lambda/D$ 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 ${\sim}10^{-6}$ Torr and over a range of bandpasses with central wavelengths from 500 to 650nm and bandwidths (BW) from $\ll 1\%$ to 15\%. Our jitter in vacuum is $<3\times10^{-3} \lambda/D$, and the best contrast performance to-date in a half-sided D-shaped dark hole is $2.2\times10^{-9}$ in a $\ll 1 \%$ BW, $4\times10^{-9}$ in a 2\% BW, and $2.5\times10^{-8}$ in a 15\% BW., Comment: 16 pages, 12 figures, SPIE Astronomical Telescopes and Instrumentation 2024

The Single Aperture Large Telescope for Universe Studies (SALTUS) is a deployable space telescope designed to provide the astrophysics community with an extremely large far-infrared (far-IR) space observatory to explore our cosmic origins. The SALTUS observatory can observe thousands of faint astrophysical targets, including the first galaxies, protoplanetary disks in various evolutionary states, and a wide variety of solar system objects. The SALTUS design architecture utilizes radiatively cooled, 14-m diameter unobscured aperture, and cryogenic instruments to enable both high spectral and spatial resolution at unprecedented sensitivity over a wavelength range largely unavailable to any existing ground or space observatories. The unique SALTUS optical design, utilizing a large inflatable off-axis primary mirror, provides superb sensitivity, angular resolution, and imaging performance at far-IR wavelengths over a wide +/-0.02 x 0.02 degree Field of View. SALTUS design, with its highly compact form factor, allows it to be readily stowed in available launch fairings and subsequently deployed in orbit.

The Single Aperture Large Telescope for Universe Studies (SALTUS) is a mission concept for a far-infrared observatory developed under the recent Astrophysics Probe Explorer opportunity from NASA. The enabling element of the program is a 14 m diameter inflatable primary mirror, M1. Due to its importance to SALTUS and potentially other space observatories, this paper focuses entirely on M1. We present a historical overview of inflatable systems, illustrating that M1 is the logical next step in the evolution of such systems. The process of design and manufacture is addressed. We examine how M1 performs in its environment in terms of operating temperature, interaction with the solar wind, and shape change due to non-penetrating particles. We investigate the longevity of the inflatant in detail and show it meets mission lifetime requirements with ample margin and discuss the development and testing to realize the flight M1., Comment: Submitted to the J. Astron. Telesc. Instrum. Syst. (JATIS), 87 pages, 36 figures, 4 tables

The SALTUS Probe mission will provide a powerful far-infrared (far-IR) pointed space observatory to explore our cosmic origins and the possibility of life elsewhere. The observatory employs an innovative deployable 14-m aperture, with a sunshield that will radiatively cool the off-axis primary to <45K. This cooled primary reflector works in tandem with cryogenic coherent and incoherent instruments that span the 34 to 660 micron far-IR range at both high and moderate spectral resolutions., Comment: 49 pages, 10 figures, 3 tables, submitted to SPIE JATIS

Paraxial diffraction modeling based on the Fourier transform has seen widespread implementation for simulating the response of a diffraction-limited optical system. For systems where the paraxial assumption is not sufficient, a class of algorithms has been developed that employs hybrid propagation physics to compute the propagation of an elementary beamlet along geometric ray paths. These "beamlet decomposition" algorithms include the well-known Gaussian Beamlet Decomposition (GBD) algorithm, of which several variants have been created. To increase the computational efficiency of the GBD algorithm, we derive an alternative expression of the technique that utilizes the analytical propagation of beamlets to tilted planes. We then use this accelerated algorithm to conduct a parameter-space search to find the optimal combination of free parameters in GBD to construct the analytical Airy function. The experiment is conducted on a consumer-grade CPU, and a high-performance GPU, where the new algorithm is 34 times faster than the previously published algorithm on CPUs, and 67,513 times faster on GPUs., Comment: 19 pages, 10 figures, Accepted to Optics Express on April 18 2024

We explore the impact of different telescope apertures on the image simulation and deconvolution processes within the context of a synthetic star field. Using HCIPy and Python programming, we modelled six telescope apertures namely Circular, Hexagonal, Elliptical (with horizontal and vertical major axes), segmented hexagonal (JWST), and obstructed circular (HST). We calculated Point Spread Functions (PSFs) for each aperture, incorporating surface shape-induced wavefront aberrations, convolved them with a synthetic star field spanning a range of brightness magnitudes, and introduced photon and detector noise layers to simulate realistic imaging conditions. Subsequent deconvolution using the Richardson-Lucy algorithm allowed for an analysis of deconvolution accuracy based on parameters like average distance between stars and differences in the number of stars between original and deconvolved images. Results indicate that the choice of telescope aperture significantly influences both simulated images and deconvolution outcomes, with brightness magnitude also playing a crucial role. The study highlights the necessity of optimizing image processing pipelines and Deconvolution algorithms tailored to each aperture shapes and their corresponding PSFs, emphasizing the pivotal role of aperture selection and optimization in achieving accurate astronomical imaging performance.

For diffraction-limited optical systems an accurate physical optics model is necessary to properly evaluate instrument performance. Astronomical observatories outfitted with coronagraphs for direct exoplanet imaging require physical optics models to simulate the effects of misalignment and diffraction. Accurate knowledge of the observatory's PSF is integral for the design of high-contrast imaging instruments and simulation of astrophysical observations. The state of the art is to model the misalignment, ray aberration, and diffraction across multiple software packages, which complicates the design process. Gaussian Beamlet Decomposition (GBD) is a ray-based method of diffraction calculation that has been widely implemented in commercial optical design software. By performing the coherent calculation with data from the ray model of the observatory, the ray aberration errors can be fed directly into the physical optics model of the coronagraph, enabling a more integrated model of the observatory. We develop a formal algorithm for the transfer-matrix method of GBD, and evaluate it against analytical results and a traditional physical optics model to assess the suitability of GBD for high-contrast imaging simulations. Our GBD simulations of the observatory PSF, when compared to the analytical Airy function, have a sum-normalized RMS difference of ~10^-6. These fields are then propagated through a Fraunhofer model of a exoplanet imaging coronagraph where the mean residual numerical contrast is 4x10^-11, with a maximum near the inner working angle at 5x10^-9. These results show considerable promise for the future development of GBD as a viable propagation technique in high-contrast imaging. We developed this algorithm in an open-source software package and outlined a path for its continued development to increase the fidelity and flexibility of diffraction simulations using GBD., Comment: 58 pages, 15 figures, preprint version for article in press. Accepted to SPIE's Journal of Astronomical Telescopes, Instruments, and Systems on October 23 2023

The size of the optics used in observatories is often limited by fabrication, metrology, and handling technology, but having a large primary mirror provides significant benefits for scientific research. The evolution of rocket launch options enables heavy payload carrying on orbit and outstretching the telescope's form-factor choices. Moreover, cost per launch is lower than the traditional flight method, which is obviously advantageous for various novel space observatory concepts. The University of Arizona has successfully fabricated many large-scale primary optics for ground-based observatories including the Large Binocular Telescope (LBT, 8.4 meter diameter two primary mirrors), Large Synoptic Survey Telescope (now renamed to Vera C. Rubin Observatory, 8.4 meter diameter monolithic primary and tertiary mirror), and the Giant Magellan Telescope (GMT, 8.4 meter diameter primary mirror seven segments). Launching a monolithic primary mirror into space could bypass many of the difficulties encountered during the assembly and deployment of the segmented primary mirrors. However, it might bring up unprecedented challenges and hurdles, also. We explore and foresee the expected challenges and evaluate them. To estimate the tolerance and optical error budget of a large optical system in space such as three mirror anastigmat telescope, we have developed a methodology that considers various errors from design, fabrication, assembly, and environmental factors., Comment: 6 pages, presented August 2023 at SPIE Optics+Photonics, San Diego, CA, USA

Extreme wavefront correction is required for coronagraphs on future space telescopes to reach 1e-8 or better starlight suppression for the direct imaging and characterization of exoplanets in reflected light. Thus, a suite of wavefront sensors working in tandem with active and adaptive optics are used to achieve stable, nanometer-level wavefront control over long observations. In order to verify wavefront control systems comprehensive and accurate integrated models are needed. These should account for any sources of on-orbit error that may degrade performance past the limit imposed by photon noise. An integrated model of wavefront sensing and control for a space-based coronagraph was created using geometrical raytracing and physical optics propagation methods. Our model concept consists of an active telescope front end in addition to a charge-6 vector vortex coronagraph instrument. The telescope uses phase retrieval to guide primary mirror bending modes and secondary mirror position to control the wavefront error within tens of nanometers. The telescope model is dependent on raytracing to simulate these active optics corrections for compensating the wavefront errors caused by misalignments and thermal gradients in optical components. Entering the coronagraph, a self-coherent camera is used for focal plane wavefront sensing and digging the dark hole. We utilize physical optics propagation to model the coronagraph's sensitivity to mid and high-order wavefront errors caused by optical surface errors and pointing jitter. We use our integrated models to quantify expected starlight suppression versus wavefront sensor signal-to-noise ratio., Comment: 15 pages, 11 figures, SPIE Optics and Photonics 2023

New development approaches, including launch vehicles and advances in sensors, computing, and software, have lowered the cost of entry into space, and have enabled a revolution in low-cost, high-risk Small Satellite (SmallSat) missions. To bring about a similar transformation in larger space telescopes, it is necessary to reconsider the full paradigm of space observatories. Here we will review the history of space telescope development and cost drivers, and describe an example conceptual design for a low cost 6.5 m optical telescope to enable new science when operated in space at room temperature. It uses a monolithic primary mirror of borosilicate glass, drawing on lessons and tools from decades of experience with ground-based observatories and instruments, as well as flagship space missions. It takes advantage, as do large launch vehicles, of increased computing power and space-worthy commercial electronics in low-cost active predictive control systems to maintain stability. We will describe an approach that incorporates science and trade study results that address driving requirements such as integration and testing costs, reliability, spacecraft jitter, and wavefront stability in this new risk-tolerant "LargeSat" context., Comment: Presented at SPIE, Optics+Photonics 2023, Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV in San Diego, CA, USA. Minor typos corrected and DOI added 2023 Oct 19th

The utilization of a 6.5m monolithic primary mirror in a compact three-mirror anastigmat (TMA) telescope design offers unprecedented capabilities to accommodate various next generation science instruments. This design enables the rapid and efficient development of a large aperture telescope without segmented mirrors while maintaining a compact overall form factor. With its exceptional photon collection area and diffraction-limited resolving power, the TMA design is ideally suited for both the ground and space active/adaptive optics concepts, which require the capture of natural guide stars within the field of view for wavefront measurement to correct for misalignments and shape deformation caused by thermal gradients. The wide field of view requirement is based on a statistical analysis of bright natural guide stars available during observation. The primary mirror clear aperture, compactness requirement, and detector pixel sizes led to the choice of TMA over simpler two-mirror solutions like Ritchey-Chretien (RC) telescopes, and the TMA design offers superior diffraction-limited performance across the entire field of view. The standard conic surfaces applied to all three mirrors (M1, M2, and M3) simplify the optical fabrication, testing, and alignment process. Additionally, the TMA design is more tolerant than RC telescopes. Stray light control is critical for UV science instrumentation, and the field stop and Lyot stop are conveniently located in the TMA design for this purpose., Comment: Presented at SPIE, Optics+Photonics 2023, Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV in San Diego, CA, USA

Continuous wavefront sensing on future space telescopes allows relaxation of stability requirements while still allowing on-orbit diffraction-limited optical performance. We consider the suitability of phase retrieval to continuously reconstruct the phase of a wavefront from on-orbit irradiance measurements or point spread function (PSF) images. As phase retrieval algorithms do not require reference optics or complicated calibrations, it is a preferable technique for space observatories, such as the Hubble Space Telescope or the James Webb Space Telescope. To increase the robustness and dynamic range of the phase retrieval algorithm, multiple PSF images with known amount of defocus can be utilized. In this study, we describe a recently constructed testbed including a 97 actuator deformable mirror, changeable entrance pupil stops, and a light source. The aligned system wavefront error is below ~30nm. We applied various methods to generate a known wavefront error, such as defocus and/or other aberrations, and found the accuracy and precision of the root mean squared error of the reconstructed wavefronts to be less than ~10nm and ~2nm, respectively. Further, we discuss the signal-to-noise ratios required for continuous dynamic wavefront sensing. We also simulate the case of spacecraft drifting and verify the performance of the phase retrieval algorithm for continuous wavefront sensing in the presence of realistic disturbances.

Integrated optical models allow for accurate prediction of the as-built performance of an optical instrument. Optical models are typically composed of a separate ray trace and diffraction model to capture both the geometrical and physical regimes of light. These models are typically separated across both open-source and commercial software that don't interface with each other directly. To bridge the gap between ray trace models and diffraction models, we have built an open-source optical analysis platform in Python called Poke that uses commercial ray tracing APIs and open-source physical optics engines to simultaneously model scalar wavefront error, diffraction, and polarization. Poke operates by storing ray data from a commercial ray tracing engine into a Python object, from which physical optics calculations can be made. We present an introduction to using Poke, and highlight the capabilities of two new propagation physics modules that add to the utility of existing scalar diffraction models. Gaussian Beamlet Decomposition is a ray-based approach to diffraction modeling that allows us to integrate physical optics models with ray trace models to directly capture the influence of ray aberrations in diffraction simulations. Polarization Ray Tracing is a ray-based method of vector field propagation that can diagnose the polarization aberrations in optical systems. Poke has been recently used to study the next generation of astronomical observatories, including the ground-based Extremely Large Telescopes and a 6 meter space telescope early concept for NASA's Habitable Worlds Observatory., Comment: 11 Pages, 9 Figures, Published in Proceedings of SPIE Optical Modeling and Performance Predictions XIII Paper 12664-5

In the development of space-based large telescope systems, having the capability to perform active optics correction allows correcting wavefront aberrations caused by thermal perturbations so as to achieve diffraction-limited performance with relaxed stability requirements. We present a method of active optics correction used for current ground-based telescopes and simulate its effectiveness for a large honeycomb primary mirror in space. We use a finite-element model of the telescope to predict misalignments of the optics and primary mirror surface errors due to thermal gradients. These predicted surface error data are plugged into a Zemax ray trace analysis to produce wavefront error maps at the image plane. For our analysis, we assume that tilt, focus and coma in the wavefront error are corrected by adjusting the pointing of the telescope and moving the secondary mirror. Remaining mid- to high-order errors are corrected through physically bending the primary mirror with actuators. The influences of individual actuators are combined to form bending modes that increase in stiffness from low-order to high-order correction. The number of modes used is a variable that determines the accuracy of correction and magnitude of forces. We explore the degree of correction that can be made within limits on actuator force capacity and stress in the mirror. While remaining within these physical limits, we are able to demonstrate sub-25 nm RMS surface error over 30 hours of simulated data. The results from this simulation will be part of an end-to-end simulation of telescope optical performance that includes dynamic perturbations, wavefront sensing, and active control of alignment and mirror shape with realistic actuator performance., Comment: 8 pages, 6 figures, presented at SPIE Optics + Photonics 2023

Polarization observations through the next-generation large telescopes will be invaluable for exploring the magnetic fields and composition of jets in AGN, multi-messenger transients follow-up, and understanding interstellar dust and magnetic fields. The 25m Giant Magellan Telescope (GMT) is one of the next-generation large telescopes and is expected to have its first light in 2029. The telescope consists of a primary mirror and an adaptive secondary mirror comprising seven circular segments. The telescope supports instruments at both Nasmyth as well as Gregorian focus. However, none of the first or second-generation instruments on GMT has the polarimetric capability. This paper presents a detailed polarimetric modeling of the GMT for both Gregorian and folded ports for astronomical B-K filter bands and a field of view of 5 arc minutes. At 500nm, The instrumental polarization is 0.1% and 3% for the Gregorian and folded port, respectively. The linear to circular crosstalk is 0.1% and 30% for the Gregorian and folded ports, respectively. The Gregorian focus gives the GMT a significant competitive advantage over TMT and ELT for sensitive polarimetry, as these telescopes support instruments only on the Nasmyth platform. We also discuss a list of polarimetric science cases and assess science case requirements vs. the modeling results. Finally, we discuss the possible routes for polarimetry with GMT and show the preliminary optical design of the GMT polarimeter., Comment: 13 pages, 5 figures,SPIE Optics + Photonics 2023 conference proceeding, Paper no 12690-20

Metasurfaces, optics made from subwavelength-scale nanostructures, have been limited to millimeter-sizes by the scaling challenge of producing vast numbers of precisely engineered elements over a large area. In this study, we demonstrate an all-glass 100 mm diameter metasurface lens (metalens) comprising 18.7 billion nanostructures that operates in the visible spectrum with a fast f-number (f/1.5, NA=0.32) using deep-ultraviolet (DUV) projection lithography. Our work overcomes the exposure area constraints of lithography tools and demonstrates that large metasurfaces are commercially feasible. Additionally, we investigate the impact of various fabrication errors on the imaging quality of the metalens, several of which are unique to such large area metasurfaces. We demonstrate direct astronomical imaging of the Sun, the Moon, and emission nebulae at visible wavelengths and validate the robustness of such metasurfaces under extreme environmental thermal swings for space applications.

We present Hyperion, a mission concept recently proposed to the December 2021 NASA Medium Explorer announcement of opportunity. Hyperion explores the formation and destruction of molecular clouds and planet-forming disks in nearby star-forming regions of the Milky Way. It does this using long-slit, high-resolution spectroscopy of emission from fluorescing molecular hydrogen, which is a powerful far-ultraviolet (FUV) diagnostic. Molecular hydrogen (H2) is the most abundant molecule in the universe and a key ingredient for star and planet formation, but is typically not observed directly because its symmetric atomic structure and lack of a dipole moment mean there are no spectral lines at visible wavelengths and few in the infrared. Hyperion uses molecular hydrogen's wealth of FUV emission lines to achieve three science objectives: (1) determining how star formation is related to molecular hydrogen formation and destruction at the boundaries of molecular clouds; (2) determining how quickly and by what process massive star feedback disperses molecular clouds; and (3) determining the mechanism driving the evolution of planet-forming disks around young solar-analog stars. Hyperion conducts this science using a straightforward, highly-efficient, single-channel instrument design. Hyperion's instrument consists of a 48 cm primary mirror, with an f/5 focal ratio. The spectrometer has two modes, both covering 138.5-161.5 nm bandpasses. A low resolution mode has a spectral resolution of R>10,000 with a slit length of 65 arcmin, while the high resolution mode has a spectral resolution of R>50,000 over a slit length of 5 armin. Hyperion occupies a 2 week long, high-earth, Lunar resonance TESS-like orbit, and conducts 2 weeks of planned observations per orbit, with time for downlinks and calibrations. Hyperion was reviewed as Category I, which is the highest rating possible, but was not selected., Comment: Accepted to JATIS, 9 Figures

The development of spaceborne coronagraphic technology is of paramount importance to the detection of habitable exoplanets in visible light. In space, coronagraphs are able to bypass the limitations imposed by the atmosphere to reach deeper contrasts and detect faint companions close to their host star. To effectively test this technology in a flight-like environment, a high-contrast imaging testbed must be designed for operation in a thermal vacuum (TVAC) chamber. A TVAC-compatible high-contrast imaging testbed is undergoing development at the University of Arizona inspired by a previous mission concept: The Coronagraphic Debris and Exoplanet Exploring Payload (CDEEP). The testbed currently operates at visible wavelengths and features a Boston Micromachines Kilo-C DM for wavefront control. Both a vector vortex coronagraph and a knife-edge Lyot coronagraph operating mode are under test. The optics will be mounted to a 1 x 2 meter pneumatically isolated optical bench designed to operate at 10^-8 torr and achieve raw contrasts of 10^-8 or better. The validation of our optical surface quality, alignment procedure, and first light results are presented. We also report on the status of the testbed's integration in the vaccum chamber., Comment: 14 pages, 9 figures

The 2020 Decadal Survey on Astronomy and Astrophysics endorsed space-based high contrast imaging for the detection and characterization of habitable exoplanets as a key priority for the upcoming decade. To advance the maturity of starlight suppression techniques in a space-like environment, we are developing the Space Coronagraph Optical Bench (SCoOB) at the University of Arizona, a new thermal vacuum (TVAC) testbed based on the Coronagraphic Debris Exoplanet Exploring Payload (CDEEP), a SmallSat mission concept for high contrast imaging of circumstellar disks in scattered light. When completed, the testbed will combine a vector vortex coronagraph (VVC) with a Kilo-C microelectromechanical systems (MEMS) deformable mirror from Boston Micromachines Corp (BMC) and a self-coherent camera (SCC) with a goal of raw contrast surpassing $10^{-8}$ at visible wavelengths. In this proceedings, we report on our wavefront sensing and control efforts on this testbed in air, including the as-built performance of the optical system and the implementation of algorithms for focal-plane wavefront control and digging dark holes (regions of high contrast in the focal plane) using electric field conjugation (EFC) and related algorithms., Comment: 7 pages, 5 figures, SPIE Astronomical Telescopes and Instrumentation 2022

The Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS) is a proposed space telescope with a 14 m inflatable primary reflector that will perform high spectral resolution observations at terahertz frequencies with heterodyne receivers. The telescope consists of an inflatable metallized polymer membrane that serves as the primary antenna, followed by aberration correction optics, and a scanner that enables a 0.1 degrees Field of Regards while achieving diffraction limited performance over wavelength range from 63 to 660 {\mu}m. Here the parametric solution space of the OASIS inflatable telescope design is systematically investigated by establishing analytical relations among figure of merits including 1st order geometrical photon collection area and the size of correction optics. The 1st order solution was further optimized by ray-trace code by incorporating numerically calculated mirror shape with pre-formed membrane gores. Design study shows that a space-based telescope with an effective photon collection area of over 90m2 can be achieved utilizing a 14m inflatable aperture., Comment: 35 Pages, 15 Figures, 9 Tables

Chemistry along the star- and planet-formation sequence regulates how prebiotic building blocks -- carriers of the elements CHNOPS -- are incorporated into nascent planetesimals and planets. Spectral line observations across the electromagnetic spectrum are needed to fully characterize interstellar CHNOPS chemistry, yet to date there are only limited astrochemical constraints at THz frequencies. Here, we highlight advances to the study of CHNOPS astrochemistry that will be possible with the Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS). OASIS is a NASA mission concept for a space-based observatory that will utilize an inflatable 14-m reflector along with a heterodyne receiver system to observe at THz frequencies with unprecedented sensitivity and angular resolution. As part of a survey of H2O and HD towards ~100 protostellar and protoplanetary disk systems, OASIS will also obtain statistical constraints on the inventories of light hydrides including NH3 and H2S towards protoplanetary disks, as well as complex organics in protostellar hot corinos and envelopes. Line surveys of additional star-forming regions, including high-mass hot cores, protostellar outflow shocks, and prestellar cores, will also leverage the unique capabilities of OASIS to probe high-excitation organics and small hydrides, as is needed to fully understand the chemistry of these objects., Comment: Accepted to Frontiers in Astronomy and Space Sciences

The Coronagraphic Debris Exoplanet Exploring Payload (CDEEP) is a Small-Sat mission concept for high contrast imaging of circumstellar disks. CDEEP is designed to observe disks in scattered light at visible wavelengths at a raw contrast level of 10^-7 per resolution element (10^-8 with post processing). This exceptional sensitivity will allow the imaging of transport dominated debris disks, quantifying the albedo, composition, and morphology of these low-surface brightness disks. CDEEP combines an off-axis telescope, microelectromechanical systems (MEMS) deformable mirror, and a vector vortex coronagraph (VVC). This system will require rigorous testing and characterization in a space environment. We report on the CDEEP mission concept, and the status of the vacuum-compatible CDEEP prototype testbed currently under development at the University of Arizona, including design development and the results of simulations to estimate performance., Comment: 17 pages, 12 figures, Published in proceedings of SPIE Astronomical Telescopes + Instrumentation 2020

The design of a CubeSat telescope for academic research purposes must balance complicated optical and structural designs with cost to maximize performance in extreme environments. Increasing the CubeSat size (eg. 6U to 12U) will increase the potential optical performance, but the cost will increase in kind. Recent developments in diamond-turning have increased the accessibility of aspheric aluminum mirrors, enabling a cost-effective regime of well-corrected nanosatellite telescopes. We present an all-aluminum versatile CubeSat telescope (VCT) platform that optimizes performance, cost, and schedule at a relatively large 95 mm aperture and 0.4 degree diffraction limited full field of view stablized by MEMS fine-steering modules. This study features a new design tool that permits easy characterization of performance degradation as a function of spacecraft thermal and structural disturbances. We will present details including the trade between on- and off-axis implementations of the VCT, thermal stability requirements and finite-element analysis, and launch survival considerations. The VCT is suitable for a range of CubeSat borne applications, which provides an affordable platform for astronomy, Earth-imaging, and optical communications., Comment: 11 pages, 9 figures, published in Optical Engineering + Applications conference in SPIE Optics + Photonics San Diego 2021