NASA astronauts Butch Wilmore and Suni Williams arrived at the ISS aboard Boeing's Starliner spacecraft last June. The duo were flying the capsule's first crewed flight test, which was expected to stay in orbit for about 10 days before flying the pair back to Earth.

Four SpaceX astronauts are geared up inside of a SpaceX rocket to launch Friday afternoon to the International Space Station to rescue two stuck NASA astronauts.