Check out astronaut Don Pettit and his big collection of Nikon DSLRs and lenses. NASA has been big on Nikon for several years, ordering 11 Nikon D3s bodies a couple of years ago and 76 Nikon D2Xs bodies before that.
The cameras are modified to withstand the rigors of photography in space – including capturing extravehicular activities with the Nikon D2Xs based on the last word we had from Nikon.
I wonder when they will get the new D4 or D800 on board the International Space Station?