There was a project that attempted to set up full bitcoin nodes in low earth orbit satellites.
It was called BitSat, lead by Jeff Garzik.
The project has been cancelled, but they did take some serious consideration to implement the idea.
The thing is to maintain these constellations it should have a viable business model, these nanosatellites in LEO could last about 1 to 3 yrs (several factors can shorten or lengthen its operational lifetime).
Regarding to using lasers in satellites for communication, there are several proposals, this is one of them:
PS: Considering that the SafeNetwork is quite unique in its incentive model with several potential revenue streams, there MAY be a way of supporting our own satellite network and getting the network pay itself its costs. Running a bitcoin node in space is quite limited businesswise compared to running a SafeCoin farmer in space 24/7…