The development of a satellite on-board microcomputer

The article discusses a microcomputer for on-board satellite applications such as attitude and orbit control. The computer has an all CMOS design and makes extensive use of large scale integration, yielding high speed, low power consumption, and a small size. The modular packaging scheme makes it possible to assemble any number of different modules for specific mission requirements. Extensive software already exists for the micro-computer since the architecture and instructions are the same as for the PDP81E minicomputer. Consideration is given to a prototype having serial and parallel ports. The memory can have up to 32 K words in 2 K blocks. A programmable timer is used for real-time applications. A bench model is presently available for control and program development. It has serial and parallel digital input/output ports which interface at 10-volt CMOS levels. The system may be operated at 5 volts which reduces the power consumption to 25% and reduces operating speed to 50%.