Over the weekend, Russian cosmonauts were able to restart two flight control computers on the International Space Station that had been crashing for the past few days. They tracked the problem down to a faulty surge protector which they were able to bypass. Props to those resourceful Russians, but it doesn’t give you much confidence in the ISS electronics. Especially since if they had not been able to fix the computer glitch, they would have had to evacuate the station.
Turns out that those computers (made in Germany) are a vintage design, made from 12-year old computer chips.
The computers use radiation-hardened ERC32 three-chip processors that came from the factory in 1995 or so. The chips had to go through a grueling round of tests, during which some serious floating-point glitches were identified and fixed. Then they were incorporated into the DMS-R computers that went up with the Russian-built Zvezda module in 2000.
Go another level deeper, and you’ll find that the ERC32 chips are based on the SPARC V7 chip architecture, which was pioneered by Sun Microsystems and came out in 1986.
The software running on those chips has a California connection as well: It’s written on top of the VxWorks operating system, produced by Wind River Systems in Alameda, Calif. VxWorks, a Unix-like real-time programming platform, is a popular choice for spacecraft software: It was used on the 1997 Mars Pathfinder mission as well as NASA’s Stardust probe and the still-operating Mars Exploration Rovers.