Autonomous navigation and orbit control can provide both significant operations cost reduction and increased mission performance. By controlling the orbit to match a chosen reference, ground operations are significantly reduced and scheduling becomes highly predictable. In addition, the system uses less propellant than traditional orbit maintenance. Microcosm flight demonstrated the first fully autonomous spacecraft navigation system, MANS, on the TAOS mission in 1994 and the first fully autonomous Orbit Control Kit, OCK, on UoSAT-12 in 1999. MANS used the Sun/Moon/Earth reference set for fully autonomous orbit determination and OCK used a GPS receiver for a navigation source. With modern sensor and processor technology, it is now possible to extend autonomous navigation to the use of stars and a central planet. This provides an exceptionally robust navigation solution for planetary missions with both singularity-free deterministic and high accuracy Kalman Filter solutions available. In turn, OCK can make use of the autonav solution to provide autonomous absolute orbit control independent of any external data or commands. Microcosm has a current contract with NASA JSC to develop accuracy estimates for various planetary autonav scenarios.
Wertz, J.R. 5th Annual Symposium on Reducing the Cost of Spacecraft Ground Systems and Operations, Pasadena, CA. July 8–11, 2003.