Your assumptions are correct. And this is how the spacecraft industry operates. In fact, like rack units, CubeSats have "1U", "3U", etc. Spacecraft components a

Your assumptions are correct. And this is how the spacecraft industry operates. In fact, like rack units, CubeSats have "1U", "3U", etc. Spacecraft components and instruments are modular. Data interfaces vary, but 1553, SpaceWire, and RS-422 UART are all quite popular. The part that all the instruments and components bolt to are called the bus. Aerospace companies have standard buses. The huge variable is the mission itself. Your blade server analogy is too narrow. Look at applications of computers on the ground. If you want to put a computer on a collar to track wolves, a blade server doesn't work. If you want a computer to take with you on a jog, a smartphone is appropriate. If you want to run a data center, a blade is great. Spacecraft vary just like this. JWST is the size of a tennis court. KickSat was the size of a cracker. The environments they operate in are crazy. The Voyagers are in deep space a light day away. Some spacecraft are just a few hundred kilometers over your head. A one-size fits all approach doesn't work.