Wavefront sensing and controls for the James Webb Space Telescope

Acton, D. Scott; Knight, J. Scott; Contos, Adam R.; Grimaldi, Stefano; Terry, J. L.; Lightsey, Paul A.; Barto, Allison; League, B.; Dean, Bruce H.; Smith, J. Scott; Bowers, Charles W.; Aronstein, David L.; Feinberg, Lee; Hayden, William L.; Comeau, Thomas; Soummer, Rémi; Elliott, Erin; Perrin, Marshall D.; Starr, Carl

doi:10.1117/12.925015

Cited by 65 publications

(39 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 the aperture is composed of 5 rings of 1.15 m reflective segments, separated by 6 mm, with a central obscuration covering the equivalent area of the inner two rings, for a total of 120 active segments. The segment's actuation architecture and the envisioned basic alignment and commissioning procedures are very similar to one implemented on JWST, 2 albeit with a larger number of degrees of freedom. However in order to deliver the exquisite wavefront stability required for exo-earth imaging the LUVOIR team is studying the addition of edge sensors along with an extra fine mechanisms with picometer resolution on each actuator.…”

Section: Introductionmentioning

confidence: 73%

The LUVOIR architecture ``A'' coronagraph instrument

Pueyo

Zimmerman

Bolcar

et al. 2017

UV/Optical/IR Space Telescopes and Instruments: Innovative Technologies and Concepts VIII

View full text Add to dashboard Cite

In preparation for the Astro 2020 Decadal Survey NASA has commissioned the study four flagship missions spanning to a wide range of observable wavelengths: the Origins Space Telescope (OST, formerly the Far-Infrared Surveyor), Lynx (formerly the X-ray Surveyor), the Large UV/Optical/Infrared Surveyor (LUVOIR) and the Habitable Exoplanet Imager (HabEx). One of the key scientific objectives of the latter two is the detection and characterization of the earth-like planets around nearby stars using the direct imaging technique (along with a broad range of investigations regarding the architecture of and atmospheric composition exoplanetary systems using this technique). As a consequence dedicated exoplanet instruments are being studied for these mission concepts. This paper discusses the design of the coronagraph instrument for the architecture "A" (15 meters aperture) of LUVOIR. The material presented in this paper is aimed at providing an overview of the LUVOIR coronagraph instrument. It is the result of four months of discussions with various community stakeholders (scientists and technologists) regarding the instrument's basic parameters followed by meticulous design work by the the GSFC Instrument Design Laboratory team. In the first section we review the main science drivers, presents the overall parameters of the instrument (general architecture and backend instrument) and delve into the details of the currently envisioned coronagraph masks along with a description of the wavefront control architecture. Throughout the manuscript we describe the trades we made during the design process. Because the vocation of this study is to provide a baseline design for the most ambitious earth-like finding instrument that could be possibly launched into the 2030's, we have designed an complex system privileged that meets the ambitious science goals out team was chartered by the LUVOIR STDT exoplanet Working Group. However in an effort to minimize technological risk we tried to maximize the number of technologies that will be matured by the WFIRST coronagraph instruments.

show abstract

Section: Introductionmentioning

confidence: 73%

The LUVOIR architecture ``A'' coronagraph instrument

Pueyo

Zimmerman

Bolcar

et al. 2017

UV/Optical/IR Space Telescopes and Instruments: Innovative Technologies and Concepts VIII

View full text Add to dashboard Cite

show abstract

“…The Wavefront Sensing and Control process [9] will assist in getting it fully aligned and keeping it at optimal configuration on orbit. The process relies on knowledge of the system's exit pupil distortion and amplitude function to generate accurate estimates for the system's wavefront error.…”

Section: Accurate Wavefront Sensingmentioning

confidence: 99%

Fine guidance sensor/near-infrared imager and slitless spectrograph on James Webb Space Telescope: pupil alignment methodology and metrology

Maszkiewicz

Rowlands

Aldridge

et al. 2017

International Conference on Space Optics — ICSO 2016

View full text Add to dashboard Cite

“…Limited by the mass and volume constraints of a launch vehicle, active space telescopes generally use the science instruments to monitor the wavefront periodically. [7][8][9][10] As a result, there is a significant cost associated with each wavefront measurement; since science observations and wavefront measurements cannot be performed simultaneously, each wavefront measurement reduces the observatory efficiency. This cost is amplified for control schemes that require a postcorrection wavefront measurement to verify the actuator motions, and it provides one incentive to limit the number of corrections.…”

Section: Introductionmentioning

confidence: 99%

“…We do not discuss the details of how the wavefront measurements are to be obtained nor how the desired controls are applied via spacecraft actuators; these topics have been discussed at length in other papers. 6,7,11 Our focus here is on the question of how often sensing and control should take place and how multiple sensing measurements may be combined in order to optimize performance. Although our analysis is based on JWST specifically, the general approach taken is also applicable to other missions, such as the proposed Astrophysics Focused Telescope Assets (AFTA) and Advanced Technology Large-Aperture Space Telescope (ATLAST) mission concepts.…”

Section: Introductionmentioning

confidence: 99%

Improving active space telescope wavefront control using predictive thermal modeling

Gersh-Range

Perrin

2014

J. Astron. Telesc. Instrum. Syst

View full text Add to dashboard Cite

Abstract. Active control algorithms for space telescopes are less mature than those for large ground telescopes due to differences in the wavefront control problems. Active wavefront control for space telescopes at L2, such as the James Webb Space Telescope (JWST), requires weighing control costs against the benefits of correcting wavefront perturbations that are a predictable byproduct of the observing schedule, which is known and determined in advance. To improve the control algorithms for these telescopes, we have developed a model that calculates the temperature and wavefront evolution during a hypothetical mission, assuming the dominant wavefront perturbations are due to changes in the spacecraft attitude with respect to the sun. Using this model, we show that the wavefront can be controlled passively by introducing scheduling constraints that limit the allowable attitudes for an observation based on the observation duration and the mean telescope temperature. We also describe the implementation of a predictive controller designed to prevent the wavefront error (WFE) from exceeding a desired threshold. This controller outperforms simpler algorithms even with substantial model error, achieving a lower WFE without requiring significantly more corrections. Consequently, predictive wavefront control based on known spacecraft attitude plans is a promising approach for JWST and other future active space observatories. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

show abstract

Wavefront sensing and controls for the James Webb Space Telescope

Cited by 65 publications

References 8 publications

The LUVOIR architecture ``A'' coronagraph instrument

The LUVOIR architecture ``A'' coronagraph instrument

Fine guidance sensor/near-infrared imager and slitless spectrograph on James Webb Space Telescope: pupil alignment methodology and metrology

Improving active space telescope wavefront control using predictive thermal modeling

Contact Info

Product

Resources

About