Video: Soyuz MS-01 leaves the space station for landing

For the second time in less than a week, astronauts will leave their quarters inside the International Space Station on Thursday to outfit a relocated docking adapter to eventually receive Boeing and SpaceX commercial crew capsules.

An unpiloted space plane developed by Sierra Nevada Corp. will join cargo carriers built by SpaceX and Orbital ATK to resupply the International Space Station beginning in 2019, NASA announced Thursday.

Russian commander Sergey Prokopyev, German flight engineer Alexander Gerst, and NASA astronaut Serena Auñón-Chancellor closed out a nearly 197-day space mission with a landing in Kazakhstan aboard their Soyuz MS-09 crew carry ship at 0502 GMT (12:02 a.m. EST) Thursday. The Soyuz crew undocked from the International Space Station at 0140 GMT (8:40 p.m. EST Wednesday) to begin their return to Earth.