I was always told it had to do with how long it took to get things approved. I remember when it was a big deal that the space shuttles were upgraded to 486s… in 2002.
it’s also because the smaller a transistor is, the more sensitive it is to cosmic rays. and there are a lot more cosmic rays in space than on earth. you can “rad-harden” them, but there are physical limits. as a result the most popular cpu architecture in space is the RAD750, based on the PowerPC 750 from 1997. the perseverance rover and the james webb space telescope are basically underclocked gamecubes, or those candy-colored imacs. like, perserverance runs at 133MHz and has 128MB of RAM.
I was always told it had to do with how long it took to get things approved. I remember when it was a big deal that the space shuttles were upgraded to 486s… in 2002.
it’s also because the smaller a transistor is, the more sensitive it is to cosmic rays. and there are a lot more cosmic rays in space than on earth. you can “rad-harden” them, but there are physical limits. as a result the most popular cpu architecture in space is the RAD750, based on the PowerPC 750 from 1997. the perseverance rover and the james webb space telescope are basically underclocked gamecubes, or those candy-colored imacs. like, perserverance runs at 133MHz and has 128MB of RAM.