Two American astronauts Scott Kelly and Tim Kopra conducted an emergency spacewalk on Monday morning to move a stalled rail car outside the International Space Station. They exited the ISS’ hatch at 7:45 a.m. EST, 25 minutes ahead of schedule. Kelly and Kopra are expected to spend more than three hours to latch down the Mobile Transporter, a rail car that moves the space station’s robotic arm.

US Astronauts Conduct Spacewalk To Fix Jammed Rail Car

Where to watch it live?

You can watch the spacewalk live on NASA TV. In NASA Missions Control, astronaut Mike Hopkins asked Kelly and Kopra to avoid making accidental contact because the Mobile Transporter was not secure into its usual spot. The astronauts had to move the rail car so a cargo ship carrying about 3,000 kg of supplies could dock on Wednesday. The rail car must be latched down at the Worksite 4 before the arrival of the Russian Progress 62 cargo ship on Wednesday. Progress 62 blasted off successfully from Baikonur Cosmodrome at 3:44 a.m. EST on Monday, Dec.21.

The Mobile Transporter jammed up on December 16 when flight controllers at NASA’s Mission Control center were remotely moving it to a storage point. It stopped just 4 inches from its Worksite 4 storage point near the center of the station’s main truss. NASA engineers blamed a stuck brake handle for the problem. Kelly and Kopra will also be taking care of a few other tasks during the spacewalk, time permitting.

It was Scott Kelly’s third spacewalk

It was the seventh spacewalk of the year, and third for the US astronaut Scott Kelly and second for Kopra. Kopra arrived at the ISS last week. The other four members aboard the ISIS are British astronaut Tim Peake and Russian cosmonauts Yuri Malenchenko, Mikhail Kornienko, and Sergey Volkov.

Scott Kelly and Mikhail Kornienko are on a year-long mission, which is set to end in March. Their physical and mental conditions are being studied under a one-year program to understand how a long-term stay in space affects humans. It is critical to sending humans to deep space missions, including to Mars.