Flexible GN&C architecture enables an innovative control solution to repurpose the Kepler Space Telescope

Abstract

Ball Aerospace &Technologies Corp. has developed an easily configurable and highly flexible Guidance Navigation and Control (GN&C) spacecraft architecture which is used across a wide variety of commercial and government missions. The flexibility of this architecture allowed the Kepler space telescope to continue its planet hunting and astro-seismology missions beyond its primary mission despite operating with only two reaction wheels. After surpassing the design life of the original mission, the wheel anomaly on Kepler was rectified by changing the observation architecture, the implementation of new procedures, and uploading new table parameters to the Flight Software. No changes in the vehicle’s Flight Software (FSW) were necessary, saving months of time that were better used with on-orbit testing that optimized operation in the new architecture. Ball Aerospace’s GN&C architecture allows for easy reconfiguration of operating observatories to quickly and efficiently make significant changes to the operating mode of the spacecraft to support desired changes in science and also to resolve any anomalies. After reconfiguration, the Kepler spacecraft continues to support 40 – 70 milli-arc-second stability for long duration photometric studies at multiple celestial fields-of-view (FOV). Evaluation of the photometric performance has demonstrated precision on the order of the original Kepler mission for stars brighter than 13 th magnitude. Propellant consumption is consistent across campaigns and shows that the spacecraft should have enough fuel to conduct +3.5 years of science operations, barring significant Safe Mode activity.