An Architecture for Demonstrating Space-based Optical Interferometry in LEO with a Laser Guide Star Reference
Abstract
Space-based optical interferometers could achieve dramatic improvements in diffraction-limited angular resolution compared to monolithic telescopes, while overcoming the atmospheric effects that limit ground based optical interferometers. Despite this potential, no known systems have yet been deployed in space, due to difficulties in precisely: measuring spacecraft relative positions, maneuvering for repositioning and orbit maintenance, and controlling attitude.
We propose an architecture that would demonstrate multi-telescope optical interferometry in space using only current and near-future technologies. The mission would consist of four satellites: a pair of free-flying mirrors, an optical combiner, and a laser guide star. The orbits of these components are chosen such that the length of the two optical paths are constant to within orbital perturbations. Optical actuators onboard the combiner will use the laser signal to maintain zero-optical path delay with a baseline of ~20 meters. The laser guide star satellite flies several thousand kilometers away from the combiner and mirrors to geometrically dilute the interferometer pointing errors introduced by GPS position uncertainty. Electric propulsion will allow the formation to sweep out the u-v plane over the course of several orbits, and will provide correction for long-time-scale orbital perturbations. In addition to demonstrating closed-loop wavefront control in space, this mission would collect interferometric optical measurements of bright stellar surfaces, such as Betelgeuse, to demonstrate resolved images of stellar surfaces. We have designed a simulation to estimate system performance which incorporates orbital dynamics and navigation uncertainty into synthesis imaging. The results of this simulation are presented for our proposed distributed architecture observing Betelgeuse. This mission would mature the technologies relevant to future space-based interferometers such as LIFE.- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- January 2023
- Bibcode:
- 2023AAS...24146307B