An Innovative On-Board Processor for Lightsats

The Applied Physics Laboratory has developed a flightworthy custom microprocessor that increases capability and reduces development costs of lightsat science instruments. This device, which APL calls the FRISC (Forth Reduced Instruction Set Computer), directly executes the high level language called Forth, which is ideally suited to the multitasking control and data processing environment of a spaceborne instrument processor. The FRlSC (which is available commercially as the SC32) will be flown as the on-board processor in the Magnetic Field Experiment on the Swedish Space Corporations’ Freja satellite. APL has achieved a significant increase in on-board processing capability with no increase in cost when compared to the magnetometer instrument on Freja's predecessor, the Viking satellite. These advantages are attributable to the high instruction execution rate, reduced software development effort, and shortened system integration time made possible by the nature of the microprocessor and the Forth language.