After five and a half months in space, three astronauts are homeward bound Tuesday night.
Jeff Williams, a NASA astronaut, passed command of the International Space Station over to Russian cosmonaut Anatoly Ivanishin for Expedition 49 on Monday.
Williams, who was commander for Expedition 48, and flight engineers Oleg Skripochka and Alexey Ovchinin are set to undock from the space station at 5:51 p.m. EDT. Their Soyuz spacecraft is scheduled to land in Kazakhstan at 9:14 p.m. EDT.
While on the ISS, Williams set a new record for the longest amount of time spent in space by a US astronaut. With a cumulative 534 days in space over four missions, Williams beat out Scott Kelly's record of 520, which he set earlier this year.
Williams and the space station have a long history. He was the flight engineer and lead spacewalker on the third space shuttle mission used to construct the ISS. Since then, he has also been a flight engineer on Expedition 13 and Expedition 21. He stayed on for Expedition 22 and took command.
On this trip to the space station, Williams was a flight engineer for Expedition 47 and took command for Expedition 48 when NASA astronaut Timothy Kopra left the space station with his crew in June.
During Expedition 48, Williams took part in two significant spacewalks. NASA astronaut Kate Rubins and Williams installed an International Docking Adapter to the space station that will allow commercial crewed space vehicles to dock in the future.
In a second spacewalk, the two NASA astronauts retracted a thermal radiator that was no longer in use, installed two new high definition cameras to the ISS, and performed other maintenance tasks.
In the life of the space station, astronauts have spent a total of 1,217 hours and 34 minutes on spacewalks, according to NASA.
Expedition 49 includes Ivanishin, Rubins, and Japanese flight engineer Takuya Onishi. The crew is set to double in size later this month when NASA's Shane Kimbrough and Roscomos' Sergey Ryzhikov and Andrey Borisenko arrive.