Fully autonomous, on-board orbit control was flight demonstrated on UoSAT-12. This technology was developed to reduce operations cost. It does this using less propellant than traditional orbit maintenance, but also opens a new array of potential mission applications. Because the position of the spacecraft is controlled and, therefore, known at all future times, users can plan applications without updating the spacecraft ephemeris; simple ground equipment can know the position of all system satellites at any time; and the ground track of the spacecraft can be made to follow a pre-defined path. Other applications are also described.
Wertz, J.R., G.E. Gurevich. 11th Annual AAS/AIAA Space Flight Mechanics Meeting, Santa Barbara, CA. February 11–15, 2001.