Mr. Charles Phillips Profile

Charles Phillips

at Jet Propulsion Lab

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Author

Publications (4)

SPIE Journal Paper | 8 December 2022 Open Access

Next-generation active telescope for space astronomy

Stefan Martin, Charles Lawrence, David Redding, Bertrand Mennesson, John Rodgers, Kevin Hurd, Rhonda Morgan, Renyu Hu, John Steeves, Jeffrey Jewell, Charles Phillips, Claudia Pineda, Ned Ferraro, Thibault L. Flinois

JATIS, Vol. 8, Issue 04, 044005, (December 2022) https://doi.org/10.1117/12.10.1117/1.JATIS.8.4.044005

KEYWORDS: Telescopes, Space telescopes, Equipment, Mirrors, Astronomical telescopes, Astronomy, Exoplanets, Planets, Coronagraphy, Stars

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We present a design for an active telescope for space astronomy. The telescope is capable of both exoplanet work and general astronomy over wavelengths from ∼100 nm up to 5 μm. The primary mirror is 6 m in diameter, formed by 16 mirror segments that are precisely phased and supported on rigid body actuators and with segment optical surface figures fine-tuned using surface figure actuators. The active primary forms a large deformable mirror (DM) with wavefront error (WFE) correction at the entrance pupil. Thus the largest source of WFE can be removed at the source and is corrected over the entire field of view. This enables diffraction-limited performance at 400 nm and a more efficient optical system over a broader wavelength range than could be achieved by a small DM at a downstream relayed pupil. The telescope is passively cooled to below 100 K at Sun–Earth L2, enabling astronomical-background-limited observations out to 5 μm. Launched on a SpaceX Starship or alternatively National Aeronautics and Space Administration’s Space Launch System, the telescope requires minimal deployments. A 72-m-diameter starshade provides a contrast ratio better than 10 − 10 for exoplanet science. Near the visible region, with a 108% working bandwidth from 300 to 1000 nm, a working distance of 120 Mm provides a 51-mas inner working angle (IWA). This band can be moved to shorter or longer wavelengths by adjusting the starshade range from the telescope. Our first-ever thermal analysis of such a starshade shows that a temperature below 100 K can be achieved over a broad range of observing directions, permitting the possibility of working into the infrared. We model the yield in exoplanets that can be observed. A starshade and associated spectrograph offer significant advantages for exoplanet characterization. They enable a much broader instantaneous spectral bandwidth (here 108%) than current coronagraphs (∼10 % to 20% bandwidth), allow both polarizations to be observed simultaneously, and have higher throughput. The IWA is twice as small as can be achieved with a coronagraph and there is no outer working angle. These differences are particularly pronounced in the UV, where coronagraph performance would be strongly affected by throughput losses, wavefront aberrations, Fresnel polarization effects at surfaces, and thermal instability.

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Proceedings Article | 13 December 2020 Presentation + Paper

ATSA: a cold, active telescope for Space Astronomy

Stefan Martin, Charles Lawrence, David Redding, Michael Rodgers, Kevin Hurd, Jeffrey Jewell, Rhonda Morgan, Charles Phillips, Claudia Pineda, Bertrand Mennesson, John Steeves

Proceedings Volume 11443, 114432A (2020) https://doi.org/10.1117/12.2575505

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Proceedings Article | 13 December 2020 Poster

Active telescope for UV-through-midIR space astronomy

Charles Lawrence, David Redding, Kevin Hurd, Jeffrey Jewell, Stefan Martin, Rhonda Morgan, Charles Phillips, Claudia Pineda, Michael Rodgers, John Steeves

Proceedings Volume 11443, 114435Z (2020) https://doi.org/10.1117/12.2563177

KEYWORDS: Space telescopes, Telescopes, Astronomy, Astronomical telescopes, Exoplanets, Imaging spectroscopy, Ultraviolet radiation, Visible radiation, Mid-IR, Optics manufacturing

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Proceedings Article | 13 October 2010 Paper

The Orbiting Carbon Observatory instrument: performance of the OCO instrument and plans for the OCO-2 instrument

Randy Pollock, Robert Haring, James Holden, Dean Johnson, Andrea Kapitanoff, David Mohlman, Charles Phillips, David Randall, David Rechsteiner, Jose Rivera, Jose Rodriguez, Mark Schwochert, Brian Sutin

Proceedings Volume 7826, 78260W (2010) https://doi.org/10.1117/12.865243

KEYWORDS: Carbon dioxide, Signal to noise ratio, Sensors, Spectroscopy, Oxygen, Calibration, Stray light, Mercury cadmium telluride, Space operations, Polarization

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