[lutorm]

Unless your two terminals are talking to the same satellite, the answer to whether your traffic has to go through a ground station depends on the topology of the space laser inter-satellite links. Whether the routing in practice allows for a terminal-to-terminal link directly without going through backhaul. I don't know. It would be a miniscule fraction of traffic.

It's worth noting that the laser links are potentially thousands of km long, so they also impose a significant link latency (even if it's lower than the corresponding fiber link.)