Two astronauts on Sunday made the first spacewalk outside China’s new orbital station to set up cameras and other equipment using a 15-meter-long (50-foot-long) robotic arm, AP reported

Liu Boming and Tang Hongbo were shown by state TV climbing out of the airlock as Earth rolled past below them. The third crew member, commander Nie Haisheng, stayed inside.

Liu and Tang spent nearly seven hours outside the station, the Chinese space agency said.

The astronauts arrived June 17 for a three-month mission aboard China’s third orbital station, part of an ambitious space program that landed a robot rover on Mars in May. Their mission comes as the ruling Communist Party celebrates the 100th anniversary of its founding.