Laser-guided space interferometer

Pogorelyuk, Leonid; Serra, Paul; Kacker, Shreeyam; Vlahakis, Sophia K.; Belsten, Nicholas; Rau, Gioia; Carpenter, Kenneth G.; Pueyo, Laurent; Douglas, Ewan S.; Cahoy, Kerri

doi:10.1117/12.2630605

Cited by 3 publications

(8 citation statements)

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“…Closely related to thermal control and observatory design is wavefront sensing and control techniques to maintain the alignment and prescription of optical surfaces and thereby preserve image quality. A range of scientific studies have investigated optimal wavefront sensing and control approaches for large space telescopes, including ultra-stable 6 m telescopes with active primary mirrors, 44 9.2 m space telescopes with formation-flying laser guide stars, [45][46][47] and active space telescopes with predictive thermal modeling. 48 There have been several research missions to test approaches to wavefront control and the TRL of these approaches for future missions.…”

Section: History Of Astronomical Space Telescope Researchmentioning

confidence: 99%

Approaches to lowering the cost of large space telescopes

Douglas,

Aldering,

Allan

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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New development approaches, including launch vehicles and advances in sensors, computing, and software, have lowered the cost of entry into space, and have enabled a revolution in low-cost, high-risk Small Satellite (SmallSat) missions. To bring about a similar transformation in larger space telescopes, it is necessary to reconsider the full paradigm of space observatories. Here we will review the history of space telescope development and cost drivers, and describe an example conceptual design for a low cost 6.5 m optical telescope to enable new science when operated in space at room temperature. It uses a monolithic primary mirror of borosilicate glass, drawing on lessons and tools from decades of experience with ground-based observatories and instruments, as well as flagship space missions. It takes advantage, as do large launch vehicles, of increased computing power and space-worthy commercial electronics in low-cost active predictive control systems to maintain stability. We will describe an approach that incorporates science and trade study results that address driving requirements such as integration and testing costs, reliability, spacecraft jitter, and wavefront stability in this new risk-tolerant "LargeSat" context.

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Section: History Of Astronomical Space Telescope Researchmentioning

confidence: 99%

Approaches to lowering the cost of large space telescopes

Douglas,

Aldering,

Allan

et al. 2023

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

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“…A Laser Guide Star (LGS) can be positioned in front of the interferometer such that all the elements are nominally aligned at the target at all times. 16 The LGS orbits in the same circular orbit but in the opposite direction from the interferometer. Hence, it stays "in front" of the interferometer for half of every orbit.…”

Section: Phase Residuals Estimation With a Laser Guide Starmentioning

confidence: 99%

“…In Section 3, we consider a setup from Ref. 16 in which a Laser Guide Star provides a phase reference for fringe tracking. In that case, the limiting factors are starlight shot noise and uncertainty in the position of the LGS.…”

Section: Introductionmentioning

confidence: 99%

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Space interferometer imaging limitations due to GPS uncertainties and parasitic forces in LEO

Pogorelyuk,

Black,

Belsten

et al. 2023

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

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Space interferometers could, in principle, exploit the relatively stable space environment and ease of baseline reconfiguration to collect measurements beyond the limitations of ground-based interferometers. In particular, a two-element interferometer could provide excellent uv-plane coverage over a few tens of low-Earth orbits. One of the challenges for free-flying interferometers is controlling the optical path distance with sub-wavelength accuracies despite the collectors flying up to hundreds of meters apart. This work considers two approaches: an artificial in-orbit laser guide star (LGS) that provides a phase reference for the space interferometer and fringe tracking on the science target itself. The two approaches (LGS vs. no LGS) would require different image processing techniques. In this work, we explore image processing with LGS phase residuals due to GPS uncertainties. We use GPS uncertainties from the GRACE-FO mission to simulate image retrieval with a 300 m baseline laser-guided space interferometer. This is done by fitting the slowly varying phase errors of complex visibility measurements. We also consider a 40 m baseline interferometer with visibility(-modulus)-only measurements. In this case, we simulate the bias in visibility due to fringe tracking in the presence of parasitic forces acting on the spacecraft. We then use a modified version of the Hybrid Input-Output phase retrieval algorithm for image reconstruction. We conclude that under our optimistic assumptions, both approaches could enable general imaging of a few large stars even with CubeSats, although an LGS would significantly improve the best resolution obtainable.

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“…Another orbital configuration proposed in Ref. 16 involves an artificial laser guide star (LGS) at a fixed direction in front of the interferometer in a counter-rotating orbit. The LGS would help with fringe tracking and provide a phase reference.…”

Section: Introductionmentioning

confidence: 99%

Space interferometer imaging limitations due to Global Positioning System uncertainties and parasitic forces in Low Earth Orbit

Pogorelyuk,

Black,

Belsten

et al. 2024

J. Astron. Telesc. Instrum. Syst.

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Space interferometers could, in principle, exploit the relatively stable space environment and ease of baseline reconfiguration to collect measurements beyond the limitations of ground-based interferometers. In particular, a two-element interferometer could provide excellent uv-plane coverage over a few tens of low Earth orbits. One of the challenges for free-flying interferometers is controlling the optical path distance with subwavelength accuracies despite the collectors flying up to hundreds of meters apart. We consider two approaches: an artificial in-orbit laser guide star (LGS) that provides a phase reference for the space interferometer and fringe tracking on the science target itself. The two approaches (LGS versus no LGS) would require different image processing techniques. In this work, we explore image processing with LGS phase residuals due to global positioning system (GPS) uncertainties. We use GPS uncertainties from the Gravity Recovery and Climate Experiment Follow-On mission to simulate image retrieval with a 300-m baseline laser-guided space interferometer. This is done by fitting the slowly varying phase errors of complex visibility measurements. We also consider a 40-m baseline interferometer with visibility(-modulus)-only measurements. In this case, we simulate the bias in visibility due to fringe tracking in the presence of parasitic forces acting on the spacecraft. We then use a modified version of the hybrid input-output phase retrieval algorithm for image reconstruction. We conclude that under our optimistic assumptions, both approaches could enable general imaging of a few large stars even with CubeSats, although an LGS would significantly improve the best resolution obtainable.

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Laser-guided space interferometer

Cited by 3 publications

References 0 publications

Approaches to lowering the cost of large space telescopes

Approaches to lowering the cost of large space telescopes

Space interferometer imaging limitations due to GPS uncertainties and parasitic forces in LEO

Space interferometer imaging limitations due to Global Positioning System uncertainties and parasitic forces in Low Earth Orbit

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