The existence of starlink proves that this is false. Look at most current pitches, they don’t talk about GW-class monsters anymore. There’s absolutely nothing stopping a 20-30kW satellite bus the size of starlink (or I guess up to 100kW? once starship is available - it’s all about payload fairing diameter) from hosting ~1 rack of compute and antennas. The economics may or may not make sense, we’ll have to see.
There’s very little research work needed to make this happen; it’s all about engineering some satellite buses and having them fly in close formation to get a “data center”. And this group of satellites in sun-synchronous orbit would relay to a comms constellation e.g. starlink itself) and operate as a global scale data center. The heat management and orbital mechanics are all straight forward really.
I don’t think Sun synchronous orbit is possible except in LEO.
LEO is high risk and star link satellites deorbit or burn up all the time. Not good from a capex POV on graphics cards.
It's worth noting that GPUs have a much higher failure rate than traditional CPUs. Over 10x the failure rate due thermal stress. The amount of heat generated is very different. You can't really replace a GPU in a satellite (at least today?) which would place most of these satellites as space debris in a ~5 year horizon.
I've heard this before. A datacenter and a starlink sattelite are not in the same ballpark of power usage and heat dissipation needs. The are orders of magnitude off from each other.