Roman Space Telescope at the 2022 SPIE Meeting

July 17-22, 2022 (Montreal, Quebec, In-person)

Conference Presentations

  • Teledyne Imaging Sensors IR Focal Plane Arrays - Meghan L. Dorn (Teledyne Imaging Sensors)
    (Sunday, July 17, 9:20–9:40 a.m. EDT, Room 519 b)
    Teledyne Imaging Sensors (TIS) is a leading manufacturer of high performance infrared detectors for Astronomy. Recently, TIS has completed assembling and delivering Eighteen (18) H4RG-10 focal plane arrays that will comprise the focal plane mosaic for Roman Space Telescope. Each individual array is 4,096 by 4,096 pixels, with a pixel size of 10 x 10 microns. The Roman focal plane is the largest infrared focal plane ever made. The James Webb Space Telescope, which debuted the first science images this July, features TIS short-wave and mid-wave focal plane arrays in three of the four on-board instruments. Teledyne continues to support next generation space astronomy, ground-based astronomy, and Earth-observing spectrometers.

  • CLEoPATRA: Contemporaneous LEnsing Parallax and Autonomous TRansient Assay - A space mission concept in support of the Roman Space Telescope - Richard K. Barry (NASA GSFC)
    (Sunday, July 17, 2:00–2:20 p.m. EDT, Room 520 c)
    The Contemporaneous LEnsing Parallax and Autonomous TRansient Assay (CLEoPATRA) space mission concept is designed to provide variable-baseline simultaneous microlensing parallax measurements for NASA’s flagship Roman Space Telescope mission and for terrestrial telescopes. We here describe the design of the mission, including discussion of our efforts to develop the means to greatly reduce the data downlink bandwidth using artificial intelligence and modern fanless GPUs, FPGAs and Tensor Processing Units. We demonstrate a reduction of data downlinked by a factor of up to 28,000 permitting communications between Earth and a small, power-limited craft in deep space. We describe radiation testing of inferencing hardware, functionality of our artificial intelligence code, compressive sensing applied to photometric lightcurves and the implementation of new, integrated optics to permit a 20cm baffled telescope to fit fully inside a small scientific spacecraft.

  • Prism assembly for Roman Space Telescope Wide Field Instrument slit-less spectroscopy - Bente H. Eegholm (NASA GSFC)
    (Monday, July 18, 5:30–7:00 p.m. EDT, Room 516)
    The Roman Space Telescope is a three mirror anastigmat design with a 2.4 m primary mirror, which will provide science information on dark energy and exoplanets. The Prism Assembly is a small add-on instrument to the telescope’s Wide Field Instrument, enabling low resolution slit-less spectroscopy with a spectral resolution 70 < R < 170 across the full field from λ= 0.75 µm to 1.8 µm. The Prism Assembly is a refractive, all-spherical optical design using a glass and a CaF2 element. This presentation will give an overview of the Prism Assembly, from design and implementation, through alignment, test and calibration.

  • Nancy Grace Roman Space Telescope coronagraph EMCCD flight camera electronics development - Olivier Daigle (Nuvu Cameras Inc., Canada)
    (Monday, July 18, 5:30–7:00 p.m. EDT, Room 516)
    The development status of the EMCCD cameras behind NASA’s Nancy Grace Roman Space Telescope CGI is discussed. The CGI instrument contrast is expected to be better than 1e-9, which implies that it will be capable of seeing exoplanets with an apparent magnitude > 30. With such a low brightness, its optical detectors will perceive only a few photons per hour.

  • Simulations of polarimetric observations of debris disks through Roman Coronagraph Instrument - Ewan S. Douglas (Steward Observatory, The Univ. of Arizona)
    (Monday, July 18, 5:30–7:00 p.m. EDT, Room 516)
    The Roman coronagraph instrument will demonstrate high-contrast imaging technology, enabling imaging of faint debris disks, the discovery of inner dust belts, and the imaging of planets orbiting around these disks. Polarization studies of debris disks provide additional information on the size, distribution, and shape of the dust grains. Roman coronagraph uses two polarization modules comprising of Wollaston prism assembly to produce four orthogonally polarized images (I0, I90, I45, and I135), each measuring 3.2 arcsecs in diameter and separated by 7.5 arcsecs in the sky. The expected RMS error in the linear polarization fraction measurement is 1.66% per resolution element of 3 by 3 pixels. We present here, a mathematical model to simulate the polarized intensity images through the Roman CGI including the instrumental polarization and calibration errors.

  • Machine learning techniques to separate the cosmic from the telluric - Frederick Dauphin (STScI)
    (Monday, July 18, 5:30–7:00 p.m. EDT, Room 516)
    In the Roman era, wide-field, deep, visible-to-near infrared images will revolutionize our understanding of galaxy evolution (e.g. environments, morphologies, masses, colors). The legacy value of Roman images and low-resolution spectra (with Roman’s prism and grism) will be greatly enhanced by massively multiplexed ground-based observations in the near – future and simultaneously allow us to leverage an impressive bounty of archived spectra from Maunakea facilities. We plan to enhance ground-based NIR spectra of astrophysically interesting objects with ground-sky spectra, atmospheric data, HST spectra and images, and machine learning techniques proven to predict galaxy spectra from images.

  • Integrated Modeling Activities for NASA's Roman Space Telescope - Joseph M. Howard (NASA GSFC)
    (Tuesday, July 19, 2:10–2:30 p.m. EDT, Room 520 d)
    The Nancy Grace Roman Telescope (RST) is a NASA observatory designed to unravel the secrets of dark energy and dark matter, search for and image exoplanets, and explore many topics in infrared optics. Scheduled to launch in the mid-2020s, this 2.4 meter aperture telescope has a field of view 100 times greater than the Hubble Space Telescope. The mission is currently in its construction phase, where integrated modeling between thermal, structural, and optical models of the observatory is necessary to demonstrate science quality images over the range of operational parameters. This presentation discusses the crosschecks used in the integrated modeling process for RST, including the various flows of data between the modeling disciplines, and summarizes the current predicted performance. Additionally, several optical modeling tools are discussed, along with the specific requirements they are meant to address.

  • GPI 2.0: Characterizing self-luminous exoplanets through low-resolution infrared and optical spectroscopy - Arlene Aleman (Stanford Univ.)
    (Tuesday, July 19, 6:00–8:20 p.m. EDT, Room 516)
    Direct imaging characterization of extrasolar planets is often done at low spectral resolution. We model the spectrographs for the Gemini Planet Imager upgrade (GPI 2.0) and for the Roman Space Telescope’s Coronograph Instrument and assess each instrument’s potential for allowing observers to constrain exoplanet properties through analysis of near-infrared and optical spectra. Generating an accurate simulation involves wavelength-to-pixel mapping followed by convolution of the spectra with the LSF. Incorporating these steps enables us to ascertain how much flux lands onto a given detector pixel and to more accurately represent the blurring of spectral features. We simulated noisy observations followed by calculations of posterior distributions from maximum likelihood comparison with the SONORA 2018 model grid and a model grid of potential self-luminous Roman candidates (suggested in Lacy et al. 2019).

  • The Roman Space Telescope Optical System: Overview, Test, and Verification - Matthew R. Bolcar (NASA GSFC)
    (Wednesday, July 20, 2:20–2:40 p.m. EDT, Room 520 c)
    The Nancy Grace Roman Space Telescope (“Roman”) is NASA’s next flagship observatory. Launching in 2027, it will test theories of the accelerated expansion of the universe, as well as expand the census of exoplanets in our galaxy. These science objectives are enabled by Roman’s large field of view, agile survey capabilities, and excellent stability. The Roman optical system comprises an optical telescope assembly (OTA) and two instruments: the primary science wide-field instrument (WFI), and a technology demonstration coronagraph instrument (CGI). This paper will describe the optical system configuration and associated performance requirements and expectations, including summary results from Monte Carlo simulations of the end-to-end alignment, launch, and commissioning operations. We will describe the optical test and verification program, including stray light analysis and verification. We will also describe the use of focus-diverse phase retrieval during both test and commissioning phases.

  • Roman Space Telescope Wide Field Instrument Design Evolution - Jeanette L. Domber (Ball Aerospace)
    (Wednesday, July 20, 3:00–3:20 p.m. EDT, Room 520 c)
    The Nancy Grace Roman Space Telescope will enable advances in astrophysics by providing a large-scale survey capability in infrared wavelengths. The observatory is designed to provide data that will allow astronomers to unlock the mysteries of the universe, answering high-priority scientific questions related to the evolution of the universe and the habitability of exoplanets. Using a 2.4 m (7.9 ft) primary mirror, Roman will capture comparable quality images to Hubble, but with more than 200 times the field of view of Hubble’s near-infrared channel, enabling the observatory to conduct comprehensive and efficient surveys. The Wide Field Instrument (WFI) features a 300-megapixel mosaic focal plane assembly with 18 H4RG detectors. WFI includes filters that provide an imaging mode covering 0.48 - 2.0 μm and two slitless spectroscopy modes. To meet scientific objectives, WFI requires a stable structural and cryogenic environment. NASA designs and develops the WFI signal chain and selected.

  • Roman Optical Telescope Assembly (OTA) Build and Integration Progress - Tony L. Whitman (L3Harris Technologies, Inc.)
    (Wednesday, July 20, 2:40–3:00 p.m. EDT, Room 520 c)
    The Nancy Grace Roman Space Telescope (RST) is a Hubble-size telescope with a large field of view for large surveys of the sky, cold temperatures for enabling near infrared imaging, and controlled temperature stability for long exposures and coronagraphy. The OTA includes the primary mirror, secondary mirror, and aft optics for inserting light into the Wide Field Instrument and the Coronagraph Instrument. The testing of the optical assemblies and structures are nearly complete and ready for telescope integration. Pictures and descriptions of the assemblies will be provided, followed by performance results achieved at these level of assemblies.

  • Nancy Grace Roman Space Telescope (RST) – Demonstration of integrated thermal control system test for the optical telescope assembly - Peter Miller (L3Harris Technologies, Inc.)
    (Wednesday, July 20, 4:00–4:20 p.m. EDT, Room 518 c)
    On-orbit optical stability of the Nancy Grace Roman Space Telescope (RST) is a key requirement that enables multiple science objectives and drives multiple aspects of telescope design and analysis. Thermoelastic changes are typically large contributors to optical instability, and both extremely low CTE materials and extremely stable temperatures are needed to achieve the RST optical stability requirements. We will present the results from a test that demonstrated the L3Harris capability to sense and control temperatures to milli-kelvin levels of stability across a range of operating temperatures.

  • The Roman Space Telescope Coronagraph Technology Demonstration: Current Status and Relevance to Future Missions - Bertrand Mennesson (JPL)
    (Thursday, July 21, 10:30–10:50 a.m. EDT, Room 520 c)
    The Roman Space Telescope will be launched in the mid-2020’s with an onboard coronagraph instrument serving as a technology demonstrator for exoplanet direct imaging. The Roman Coronagraph will be capable of detecting exoplanets and circumstellar disks in visible light at an unprecedented contrast level of ~10-8 or lower. Reaching such a contrast level raises entirely new challenges that will be overcome using a combination of hardware, calibration and data processing. In particular, the Roman Coronagraph will be the first space-based coronagraphic instrument with real-time active wavefront control through the use of large format deformable mirrors, and its EMCCD detector will enable faint signal detection in photon-counting mode. The Roman Coronagraph passed its critical design review successfully in April 2021, and is now well on its path to demonstrate many core technologies at the levels required for future exo-Earth direct imaging missions.

  • Roman Coronagraph Instrument: Post-CDR Engineering Overview and Status - Ilya Y. Poberezhskiy (JPL)
    (Thursday, July 21, 10:50–11:10 a.m. EDT, Room 520 c)
    NASA’s Nancy Grace Roman Space Telescope is a flagship astrophysics mission planned for launch in mid 2020s. The coronagraph instrument on Roman will demonstrate the technology for direct imaging of exoplanets around nearby stars. The coronagraph instrument successfully passed its Critical Design Review (CDR) in April 2021, had flight-like Engineering Development Units for its unique component designs demonstrate their key requirements, and has received a number of flight hardware components. Flight and ground software development and testing are ongoing. During 2022, all coronagraph flight hardware will be completed and delivered for instrument integration and testing. We provide an overview and status of the Roman Coronagraph Instrument hardware components' development, software development and testing, performance predictions, and plans for the upcoming instrument alignment, integration, and testing.

  • Super polished mirrors for the Roman Space Telescope CoronaGraphic Instrument: design, manufacturing and optical performances - Marc Ferrari (Lab. d'Astrophysique de Marseille, France)
    (Thursday, July 21, 11:10–11:30 a.m. EDT, Room 520 c)
    NASA Roman Space Telescope mission includes a demonstrator for future space coronagraphs (CGI) requiring extremely high optical performances. The Stress Mirror Polishing (SMP) technique controlled for years at LAM allows very low SFE (few nm RMS) and micro-roughness (few Å) on the optical surfaces. Therefore, NASA selected LAM to manufacture all the Off-Axis Parabolas (OAP) for the CGI. Seven-teen mirrors will be delivered to JPL before April 2022. This paper gives an overview of the SMP process applied to OAPs stringent requirements for the CGI and performance reached on all the mirrors.

  • Nancy Grace Roman Space Telescope Coronagraph Instrument Observation Calibration Plan - Robert T. Zellum (JPL)
    (Thursday, July 21, 11:30–11:50 a.m. EDT, Room 520 c)
    NASA’s next flagship mission, the Nancy Grace Roman Space Telescope, is 2.4-meter observatory set to launch no later than May 2027. Roman features two instruments: the Wide Field Imager and the Coronagraph Instrument. Roman’s Coronagraph is a Technology Demonstration that will push the current capabilities of direct imaging, typically conducted from the ground, to smaller contrast ratios (~1E-9) and inner-working angles (3 lambda/D). In order to achieve this precision, Roman Coronagraph data must be calibrated to remove as many potential sources of error as possible. Here we present a detailed overview of the Nancy Grace Roman Space Telescope Coronagraph Instrument Observation Calibration Plan including identifying potential sources of error and how they will be mitigated via on-sky calibrations.

  • Dark hole maintenance for future coronagraphic space missions - Susan F. Redmond (Princeton Univ.)
    (Thursday, July 21, 5:50–6:10 p.m. EDT, Room 520 c)
    In this paper, we expand on our previous dark hole maintenance (DHM) results and extrapolate our experimental results to the Roman Space Telescope (RST) and a “large (~6 m aperture) infrared/optical/ultraviolet (IR/O/UV) space telescope” as recommended by the 2021 decadal survey. We develop low-photon experiments with similar noise properties to provide a representative extrapolation. The experiments are performed on the High-contrast imager for Complex Aperture Telescopes (HiCAT) at the Space Telescope Science Institute (STScI). We use the results of these DHM experiments to demonstrate post-processing capabilities. With the entire observation-to-planet-detection pipeline we will provide stellar magnitude, exposure time, and general operation limits for the aforementioned space telescopes for certain drift scenarios.

  • Absolute flux calibrations for the Nancy Grace Roman Space Telescope Coronagraph Instrument - Robert T. Zellem (JPL)
    (Thursday, July 21, 6:00–8:00 p.m. EDT, Room 516)
    The Coronagraph Instrument aboard the Nancy Grace Roman Space Telescope is expected to be a revolutionary technology demonstration in high-contrast exoplanet imaging. In order to meet the mission’s photometry and spectroscopy goals, we must identify a pair of spectrophotometric standard calibrator stars used to sufficiently test and quantify the Coronagraph’s absolute flux measurement performance.