Design of an Aberration Correction System for a Deployable Space Telescope

Design of an Aberration Correction System for a Deployable Space Telescope

van Marrewijk, Gijsbert (TU Delft Aerospace Engineering)

Kuiper, J.M. (mentor)
Dolkens, D. (mentor)

Delft University of Technology

Aerospace Engineering | Space Systems Engineering

Deployable Space Telescope

2018-05-07

Launch costs for high-resolution space telescopes for Earth observation can be reduced when the telescope mirrors are made deployable. However, such a system is subject to optical aberrations that decreases image quality. To counter these aberrations, an Aberration Correction System (ACS) is proposed that uses a deformable mirror (DM) which is calibrated by applying image sharpness optimisation. A stochastic gradient descent algorithm is applied to the output of two image detectors, such that the DM deformation can even be optimised during in-orbit scanning operations, without the need for a dedicated wavefront sensor. The effects of different sharpness metrics and algorithm settings have been analysed. With this novel control method, an average Strehl ratio of above 0.9 and 0.8 can be achieved on the central field and extreme field of the primary detector respectively. Also, in-orbit drift effects can be actively compensated without interrupting nominal operations.

Deformable mirror
image sharpness
stochastic gradient descent
space telescope
Earth observation
machine learning
monomorph mirror
ray tracing
simulation

http://resolver.tudelft.nl/uuid:ee75fe8e-7265-4b40-87ed-113f148fa75c

2019-05-07

Student theses

master thesis

© 2018 Gijsbert van Marrewijk