A Russian Soyuz spacecraft streaked into space and chased down the International Space Station Tuesday, but a problem with the ferry ship’s automated rendezvous system forced commander Yuri Malenchenko to take over manual control at the last minute.

With three space station fliers heading home Sunday after a 168-day mission, three fresh crew members made final preparations for launch three days later to boost the lab’s crew back to six in a rapid-fire rotation that will prevent any major interruption of research activity.

The Russian Soyuz MS-13 spacecraft departed the International Space Station and landed in Kazakhstan Thursday, bringing home outgoing space station commander Luca Parmitano, Soyuz pilot Alexander Skvortsov, and NASA astronaut Christina Koch, who concluded a 328-day mission, the longest-ever spaceflight by a woman. The Soyuz undocked from the station at 0550 GMT (12:50 a.m. EST) Thursday, then landed on the Kazakh steppe at 0912 GMT (4:12 a.m. EST).