ATSA: a cold, active telescope for Space Astronomy

Martin, Stefan; Lawrence, C. R.; Redding, David C.; Rodgers, Michael; Hurd, Kevin; Jewell, Jeffrey; Morgan, Rhonda; Phillips, Cynthia; Pineda, Claudia; Mennesson, Bertrand; Steeves, John

doi:10.1117/12.2575505

Cited by 4 publications

(3 citation statements)

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“…In general, H 2 S is found to show much weaker absorption lines than SO 2 such that it appears quite unlikely that present and future missions such as JWST, Ariel, or the Habitable World Observatory (HWO) (Dick et al 2019;Martin et al 2020;Ygouf et al 2020) will be able to detect H 2 S in an atmosphere like the one we modeled.…”

Section: Observability Of So 2 and H 2 Smentioning

confidence: 68%

The sulfur species in hot rocky exoplanet atmospheres

Janssen,

Woitke,

Herbort

et al. 2023

Astron Nachr

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The first JWST observations of hot Jupiters showed an unexpected detection of SO in their hydrogen‐rich atmospheres. We investigate how much sulfur can be expected in the atmospheres of rocky exoplanets and which sulfur molecules can be expected to be most abundant and detectable by transmission spectroscopy. We run thermochemical equilibrium models at the crust–atmosphere interface, considering surface temperatures 500–5000 K, surface pressures 1–100 bar, and various sets of element abundances based on common rock compositions. Between 1000 and 2000 K, we find gaseous sulfur concentrations of up to 25% above the rock in our models. SO, SO, HS, and S are by far the most abundant sulfur molecules. SO shows potentially detectable features in transmission spectra at about 4 m, between 7 and 8 m, and beyond 15 m. In contrast, the sometimes abundant HS molecule is difficult to detect in these spectra, which are mostly dominated by HO and CO. Although the molecule PS only occurs with concentrations ppm, it can cause a strong absorption feature between 0.3 and 0.65 m in some of our models for high surface pressures. The detection of sulfur molecules would enable a better characterization of the planetary surface.

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Section: Observability Of So 2 and H 2 Smentioning

confidence: 68%

The sulfur species in hot rocky exoplanet atmospheres

Janssen,

Woitke,

Herbort

et al. 2023

Astron Nachr

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“…The entirely passive thermal system eliminates the need for staged Fig. 21 The schematic layout of the thermal system. Heat pipes conduct heat from the payload adaptor plate and the AMS to radiator panels.…”

Section: Thermal Designmentioning

confidence: 99%

“…The ATSA design that we present in this paper (advanced from Ref. 21) is on-axis. An off-axis version with the same PM size will be presented in a future paper.…”

Section: Atsa: Active Telescope For Space Astrophysicsmentioning

confidence: 99%

Next-generation active telescope for space astronomy

Martin

Lawrence

Redding

et al. 2022

J. Astron. Telesc. Instrum. Syst.

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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 finetuned 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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