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

Helium leaks and thruster issues prompted NASA to extend their stay aboard the space station indefinitely — Wednesday marked their 35th day in orbit — while engineers carry out tests and analysis to better understand what caused the problems and to make sure the spacecraft can safely being Wilmore and Williams home.

A Soyuz rocket decorated to mark the 75th anniversary of the end of World War II in Europe fired into space Friday from the Baikonur Cosmodrome in Kazakhstan, sending a Progress supply ship on a fast-track, three-hour pursuit of the International Space Station.

The next three-person crew will launch to the International Space Station sometime between July 23 and July 25 after a two-month delay triggered by the failure of an unmanned Progress resupply mission in April, Russian officials said Tuesday.