Achieving high-precision pointing on ExoplanetSat: Initial feasibility analysis
Name
Pong-2010-Achieving high-precision pointing on ExoplanetSat Initial feasibility analysis.pdf
Size
4.23 MB
Format
Adobe PDF
Checksum (MD5)
3fa1c600a96031d02e99d121d9ed9282
Author(s)
Pong, Christopher Masaru
Lim, Sungyung
Smith, Matthew William
Villasenor, Jesus Noel Samonte
Seager, Sara
Miller, David W
Date Issued
July 2010
Journal
Proceedings of SPIE--the International Society for Optical Engineering
Publisher
SPIE
Citation
Christopher M. Pong, Sungyung Lim, Matthew W. Smith, David W. Miller, Jesus S. Villaseñor and Sara Seager, "Achieving high-precision pointing on ExoplanetSat: initial feasibility analysis", Proc. SPIE 7731, 77311V (2010); doi:10.1117/12.857992 © 2010 COPYRIGHT SPIE
Version
Final published version
Abstract
ExoplanetSat is a proposed three-unit CubeSat designed to detect down to Earth-sized exoplanets in an orbit out to the habitable zone of Sun-like stars via the transit method. To achieve the required photometric precision to make these measurements, the target star must remain within the same fraction of a pixel, which is equivalent to controlling the pointing of the satellite to the arcsecond level. The satellite will use a two-stage control system: coarse control will be performed by a set of reaction wheels, desaturated by magnetic torque coils, and fine control will be performed by a piezoelectric translation stage. Since no satellite of this size has previously demonstrated this high level of pointing precision, a simulation has been developed to prove the feasibility of realizing such a system. The current baseline simulation has demonstrated the ability to hold the target star to within 0.05 pixels or 1.8 arcseconds (with an 85 mm lens and 15 μm pixels), in the presence of large reaction wheel disturbances as well as external environmental disturbances. This meets the current requirement of holding the target star to 0.14 pixels or 5.0 arcseconds. Other high-risk aspects of the design have been analyzed such as the effect of changing the guide star centroiding error, changing the CMOS sampling frequency, and reaction wheel selection on the slew performance of the satellite. While these results are promising as an initial feasibility analysis, further model improvements and hardware-in-the-loop tests are currently underway.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1117/12.857992
