A CPU for use in space must first be MIL-STD-883 compliant, or equivalent, usually made of Class M or S parts. This means it has met a battery of over 100 tests including thermal, mechanical, AC electrical and DC electrical tests as well as sampling requirements for individual wafer inspections that the Department of Defense has developed to insure reliable operation.
Most CPUs that pass come from the center of a wafer. This eliminates edge defects and
generally makes for a more radiation resistant device. Also note that MOST spacecraft use many CPUs. Either for redundancy or to split tasks. Being able to separately control EACH component of a spacecraft is very important. This would be impossible if one CPU controlled them all. With each sub-system powered by its own CPU the sub-systems can be better controlled for power management and fault tolerance. Below are some of the more common processors used in space computers.
- 2006 – Synova Mongoose-V. Radiation hardened version of the MIPS R3000 running at 15 MHZ. $20k – $40k. Flown on the NASA New Horizons with redundant banks of 8 Gb flash memory.
- 2012 – BAE RAD750. Radiation hardened version of the IBM PowerPC 750. Flown on the Mars Rover, Orion Shuttle , and several DoD satellites. Similar to the IBM PowerPC 750 used in the Apple iMac G3.