US Space Shuttle runs on 1MB of RAM and 80’s technology…still

[Squilliam]

TheRealMafoo said:

As someone who has worked on Satellite hardware, I can give some insight on why this is true.

Electronic hardware needs to be Rad Hardened. This is a technique of shielding the boards and CPU's from radiation. A lot of the new stuff has just never been put through this process.

In Space, power is king. If a CPU can do every calculation you require from it, the one that takes the least amount of power is the best choice, regardless of age. The older Motorola CPU's fit this bill nicely.

I have been out of the government game for 6 years now, so not sure what they do today. But when I was working on a program just 6 years ago, with a 140 million dollar budget, we used 10 year old CPU's. Not because we didn't have any money or that government moved slow, but because out of all the CPU's on the market, they fit the requirement best.

Oh I have to add that I heard a lot of the hardware in planes is based off 386/486. Next time you take a flight, think about how old the guidance hardware running the autopilot is!

I suspect the other reason is that with a less dense chip you've got a much simpler and more robust chip by nature and you have to consider the complexity of the metalic interconnects as well as the relative size of the transistors and how vulnerable they are to cosmic rays etc. With larger transistors the energy required to 'flip a bit' is likely much higher than say if you put a modern Core i7 in orbit which was made using a 32nm process node vs several hundred/thousand nm back in the day.