While it may not be precisely what they are there for, I think it's pretty great that the astronauts aboard the International Space Station have managed to still have some fun up there--not just doing work while they orbit the Earth.
This is Samantha Cristoforetti, the first Italian woman in space, taking a quick selfie from the International Space Station. That thing you see in the background is the SpaceX Dragon supply capsule (which, interestingly, is bringing an espresso machine made specifically to work in space) to the station.
Why a Star Trek costume? Well, I guess because she was the first female Starfleet captain to take the lead role in a 'Trek' series and is thus an inspiration to many women interested in space.
I keep seeing people complaining about her bringing up this costume--are these people who live and work there not allowed to bring up some of their own things for comfort? Sure the "cost per pound" is something around 5-10k per pound, but that is for adding additional weight that is not already allocated--aka her personal belonging weight.
Either way, I think it's pretty cool. Right on Captain Cristoforetti.