Practical Limits on Nanosatellite Telescope Pointing: The Impact of Disturbances and Photon Noise

Frontiers in Astronomy and Space Sciences

Astronomy and Space Sciences

Ewan S. Douglas¹  Kevin Tracy²  Zachary Manchester² 

[1] Department of Astronomy/Steward Observatory, Tucson, AZ, United States;The Robotics Institute, Carnegie Mellon University, Pittsburgh, PA, United States;

关键词: attitude sensing and control;    environmental disturbances;    CubeSats;    astrophysics;    satellite pointing;    jitter;    nanosatellites;   

DOI  :  10.3389/fspas.2021.676252

 received in 2021-03-04, accepted in 2021-07-12,  发布年份 2021

来源: Frontiers

【 摘 要 】

Accurate and stable spacecraft pointing is a requirement of many astronomical observations. Pointing particularly challenges nanosatellites because of an unfavorable surface area–to-mass ratio and a proportionally large volume required for even the smallest attitude control systems. This work explores the limitations on astrophysical attitude knowledge and control in a regime unrestricted by actuator precision or actuator-induced disturbances such as jitter. The external disturbances on an archetypal 6U CubeSat are modeled, and the limiting sensing knowledge is calculated from the available stellar flux and grasp of a telescope within the available volume. These inputs are integrated using a model-predictive control scheme. For a simple test case at 1 Hz, with an 85-mm telescope and a single 11th magnitude star, the achievable body pointing is predicted to be 0.39 arcseconds. For a more general limit, integrating available star light, the achievable attitude sensing is approximately 1 milliarcsecond, which leads to a predicted body pointing accuracy of 20 milliarcseconds after application of the control model. These results show significant room for attitude sensing and control systems to improve before astrophysical and environmental limits are reached.

【 授权许可】

Unknown   
Copyright © 2021 Douglas, Tracy and Manchester.