This seems unlikely - if a specific number of bits in a standardized floating point representation would imply relevant calculation errors, Nasa would certainly

This seems unlikely - if a specific number of bits in a standardized floating point representation would imply relevant calculation errors, Nasa would certainly not use it. Sure, if 24 bits were already sufficient, they would not go out of their way to avoid the extra 8 bits. So in that sense you're right of course. But it's not just "Hey, single precision floats are 32 bits, so why don't we just use that!"