Arcsecond Pointing Stability on a CubeSat Platform

The interest in CubeSats has grown exponentially over the last decade. From scientists to the U.S. war fighter, the aerospace community has seen the tangible benefits of using CubeSats to satisfy key roles in their experiments and operational missions. NASA has played a significant role in fostering the growth of the CubeSat community. Exoplanet imaging is an application that requires extremely good pointing stability. NASA?s Kepler mission, launched in March 2009, is currently surveying a large section space in search of exoplanets. Follow-up measurements on specific targets identified by Kepler would be a great fit for CubeSat exoplanet imagers, as very long measurements could be taken at relatively low cost. The number of CubeSat exoplanet imagers would easily scale, allowing follow-up measurements of hundreds of potential exoplanets. Beyond imaging applications, the NASA Ames LADEE mission utilized laser communication to provide a high bandwidth long distance communication link. Laser communication was demonstrated from the moon with a beamwidth of 3 arc-seconds, requiring tight pointing stability from the ADCS. The technology developed in this SBIR could allow high bandwidth laser communication links without a separate pointing control stage, freeing up limited CubeSat payload space.

Arcsecond level jitter performance is important for low-light optical imaging applications, particularly satellite inspection missions. These missions have traditionally been restricted to government agencies, though commercial satellite inspection in the GEO belt would be useful for satellite operators to diagnose failures at a safe distance. Although most Earth imaging occurs at very short exposure windows (<1ms), increased attitude stability in a standard platform would improve the ground resolution/price ratio for these missions. There is likely commercial interest in a star tracker that can operate as a rate sensor. The rate sensor can be used as a backup to an IMU in control systems, or even as the primary sensor for precision pointing. Since the rate sensor will be relatively high bandwidth, the rate sensor technology could increase the control loop bandwidth, providing better pointing accuracy and stability at low altitudes or in the presence of other disturbance torques. More »