“But if you’re planning to send a computer on, say, a 10-year mission into deep space, then you need more staying power. The best option used to be to send lots of spare processors and cross your fingers. As your probe flew silently through the night, you would dream about chips that could fix themselves.
It’s not crazy. A type of processor called a field programmable gate array really can recover on the fly. Invented in 1984, FPGAs don’t have hardwired patterns of circuits. Instead, their wiring runs through programmable intersections called logic blocks. They’re slower than ordinary chips, and until recently their high cost limited their application to rapid prototyping of chip layouts. But advances in fabrication are finally lowering the price.”
The Voyager and Viking probes used a unique chip (RCA’s 1802) consisting of silicon mounted on sapphire, to ‘harden’ it against the extremes of temperature, electrostatic discharge and radiation to be found in the vacuum. This chip has been running since the 1970s and will keep running until around 2020, when its power will fail. Why bother having self-repairing chips, when you can have ones that are reliable (rather than our weak, cheaply manufactured commercial products.)
Moreover, space, because of its inhospitality, is a place where we can try out all those strange techniques that won’t work anywhere else. What are the chances of something shorting or air oxidising the parts? Small, with a vacuum when you’ve got a truly closed circuit. With a temperature approaching absolute zero, all those superconductive materials our scientists develop in the labs (but will work nowhere else) should work perfectly. All our computers should be in space!
Sorry, I don’t know why I’m writing about this, but I find it fascinating. I’d also like to emphasise how much I want to visit Mars.