WFIRST low order wavefront sensing and control dynamic testbed performance under the flight like photon flux

Seo, Byoung-Joon; Cady, Eric; Kern, Brian; Lam, Raymond; Marx, David; Patterson, Keith; Prada, Camilo Mejia; Shaw, John A.; Shelton, Chris; Shields, Joel; Tang, Hong; Truong, Trieu‐Kien

doi:10.1117/12.2312746

Cited by 19 publications

(23 citation statements)

References 1 publication

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“…Low-order optical errors and fast variations (such as tip/tilt due to spacecraft pointing) are controlled by the Low-Order Wavefront Sensing and Control (LOWFS/C) loop, where aberrations and motion are measured using a Zernike wavefront sensor that uses starlight rejected by the coronagraph masks. [6][7][8] The LOWFS/C loop operates with control bandwidths of ∼20 Hz and ∼2 mHz, for tip/tilt and Z4-Z11, respectively. CGI's high-contrast performance is only guaranteed for stars of Vmag≤5, as LOWFS SNR begins to degrade below this cutoff, particularly for the fast tip/tilt loop.…”

Section: Wavefront Sensing and Control For High Contrastmentioning

confidence: 99%

The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) technology demonstration

Kasdin

Bailey

Mennesson

et al. 2020

Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave

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The Coronagraph Instrument (CGI) on the Nancy Grace Roman Space Telescope will demonstrate the highcontrast technology necessary for visible-light exoplanet imaging and spectroscopy from space via direct imaging of Jupiter-size planets and debris disks. This in-space experience is a critical step toward future, larger missions targeted at direct imaging of Earth-like planets in the habitable zones of nearby stars. This paper presents an overview of the current instrument design and requirements, highlighting the critical hardware, algorithms, and operations being demonstrated. We also describe several exoplanet and circumstellar disk science cases enabled by these capabilities. A competitively selected Community Participation Program team will be an integral part of the technology demonstration and could perform additional CGI observations beyond the initial tech demo if the instrument performance warrants it.

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Section: Wavefront Sensing and Control For High Contrastmentioning

confidence: 99%

The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) technology demonstration

Kasdin

Bailey

Mennesson

et al. 2020

Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave

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“…Following the DMs, the beam is focused using a parabolic mirror onto a coronagraphic mask. The mask design has a coating that reflects out of band light to the Zernike Wavefront Sensor (ZWFS) [3] . The ZWFS is used in conjunction with the DMs to sense and correct tip and tilt.…”

Section: Habex Coronagraphmentioning

confidence: 99%

Habitable Exoplanet Observatory (HabEx) telescope and optical instruments

Martin

Kuan

Stern

et al. 2019

Techniques and Instrumentation for Detection of Exoplanets IX

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The HabEx study has developed a baseline concept for a 4 m aperture next generation space telescope operating from the ultraviolet to the infrared, capable of compelling general astrophysics and exoplanet science. HabEx carries four instruments, a UV spectrometer/imager (UVS) together with a general purpose astrophysics camera/spectrograph (HWC) and for exoplanet work, a coronagraph and a starshade. UVS reaches down to 115 nm with resolution up to 60,000 and a 3'x3' field of view. HWC operates between 370 nm and 1800 nm, again with a 3'x3' field of view; the spectral resolution is 1000 and it carries a suite of science filters. The telescope is capable of tracking both deep space and solar system objects. The coronagraph enables observations and spectroscopy at up to R=140 with instantaneous 20% bandwidth between wavelengths of 450 and 1800 nm and is intended to be used in a survey mode. However, it also backs up most of the functionality of the accompanying starshade instrument which will have superior performance for spectroscopy. The 52 m diameter starshade flies 76,600 km from the telescope and at that range has a broadband suppression of the starlight between 300 and 1000 nm. A single observation at 108% bandwidth covers a very wide spectral band at a resolution up to 140. Both coronagraph and starshade are equipped with integral field spectrometers to enable simultaneous spectroscopy of exoplanets within the field of view. This paper details the design of the telescope, the four science instruments and associated optical systems.

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“…The Roman Space Telescope CGI will make use of a spatially filtered version of the ZWFS to sense and correct low-order wavefront errors using light reflected off the coronagraph focal plane mask (FPM). [29][30][31][32] When used without spatial filtering in the image plane, the spatial resolution of a ZWFS is limited by the number of detector pixels across the beam. For context, the ZWFS is also similar in principle to a point-diffraction interferometer.…”

Section: Introductionmentioning

confidence: 99%

Wavefront sensing and control in space-based coronagraph instruments using Zernike’s phase-contrast method

Ruane

Wallace

Steeves

et al. 2020

J. Astron. Telesc. Instrum. Syst.

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Future space telescopes with coronagraph instruments will use a wavefront sensor (WFS) to measure and correct for phase errors and stabilize the stellar intensity in high-contrast images. The HabEx and LUVOIR mission concepts baseline a Zernike wavefront sensor (ZWFS), which uses Zernike's phase contrast method to convert phase in the pupil into intensity at the WFS detector. In preparation for these potential future missions, we experimentally demonstrate a ZWFS in a coronagraph instrument on the Decadal Survey Testbed in the High Contrast Imaging Testbed facility at NASA's Jet Propulsion Laboratory. We validate that the ZWFS can measure low-and mid-spatial frequency aberrations up to the control limit of the deformable mirror (DM), with surface height sensitivity as small as 1 pm, using a configuration similar to the HabEx and LUVOIR concepts. Furthermore, we demonstrate closed-loop control, resolving an individual DM actuator, with residuals consistent with theoretical models. In addition, we predict the expected performance of a ZWFS on future space telescopes using natural starlight from a variety of spectral types. The most challenging scenarios require ∼1 h of integration time to achieve picometer sensitivity. This timescale may be drastically reduced by using internal or external laser sources for sensing purposes. The experimental results and theoretical predictions presented here advance the WFS technology in the context of the next generation of space telescopes with coronagraph instruments.

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WFIRST low order wavefront sensing and control dynamic testbed performance under the flight like photon flux

Cited by 19 publications

References 1 publication

The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) technology demonstration

The Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) technology demonstration

Habitable Exoplanet Observatory (HabEx) telescope and optical instruments

Wavefront sensing and control in space-based coronagraph instruments using Zernike’s phase-contrast method

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