Butch Wilmore, Suni Williams and their two crewmates will depart the International Space Station at 1:05 a.m. ET on Tuesday (March 18), weather permitting.

Four astronauts will soon launch to the space station — a flight that will kick off a series of events culminating in the long-awaited return of NASA astronauts Suni Williams and Butch Wilmore.

For astronauts Suni Williams and Butch Wilmore, Friday's launch means they are closing in on their flight back to Earth after an unexpected nine months in orbit.