The four newcomers will spend the next few days learning the station’s ins and outs from Butch Wilmore and Suni Williams. Then it will be time for those two to end their nine-month stay and head home.

America is eagerly awaiting the return of two astronauts who have been stuck on the ISS since last June. Here's who they are.

NASA astronaut Butch Wilmore recently said that politics has nothing to do with why he and his crewmate, Suni Williams, are still in space.