Little was heard about autonomous satellite control and operations during the industrial visits. At ESA headquarters, the team was told this is one of the seven new areas ESA is now pursuing. The key advantage of an "intelligent" payload is that it requires a smaller team of specially trained ground crew to operate the satellite and its payloads. This allows the sale of satellites to customers where highly skilled technicians may not be in abundance. The first project with some autonomous control and operation is OLYMPUS.
In Japan, Toshiba presented excellent work on its ACE Autonomous Satellite Control. Toshiba developed its own 16-bit MPU radiation hard processor (CMOS 10k gate array, runs at 5 MHz) for ETS-VI. The architecture of this ACE system (Figures 2.58, 2.59 and 2.60 and Tables 2.22 and 2.23) (Handout, 21 Oct. 1992, Toshiba Corp., Space Programs Division) is excellent and well thought out; it includes a fault tolerant multi-processing operating system. The system has four CPUs with voting and failure detection for operation of attitude control. This is probably one the most advanced systems of its kind to be flown on a communications satellite.
Figure 2.58. Autonomous Satellite Control and Operation: Subsystem Autonomy in Fault-tolerance
Figure 2.59. Autonomous Satellite Control and Operation: Hierarchical Fault-tolerant Architecture
Figure 2.60. Autonomous Satellite Control and Operation: ACS Fault-tolerant Function (in the Case of Initial Acquisition Mode)
Autonomous Satellite Control and Operation
Features of ACE
Autonomous Satellite Control and Operations - Hardware Fault-Tolerant Functions