The crew at the International Space Station is celebrating an important milestone in space exploration.
Today marks the 15 year anniversary of human occupancy on the ISS.
The crew held a news conference to talk about the significance of spending that many years in space.
"The Space Station really is a bridge. It's a test bridge for the technologies that we need to develop and understand in order to have a successful trip to Mars," said Nasa astronaut Kjell Lindgren.