China is set to launch the unmanned Shenzhou XXII spacecraft on Tuesday from the Jiuquan Satellite Launch Center in the Inner Mongolia autonomous region, the China Manned Space Agency said.

The agency said in a brief statement on Monday afternoon that propellant injection for the Long March 2F carrier rocket, which will lift the robotic spacecraft, had been completed. It added that the Shenzhou XXI crew remains in good condition aboard the Tiangong space station.

No additional details about the upcoming mission were released.

According to Zhou Yaqiang of the agency's general technical bureau, Shenzhou XXII will carry a full load of cargo, including provisions for astronauts and equipment needed for Tiangong's operations.

The spacecraft had originally been scheduled to ferry the Shenzhou XXII crew to Tiangong in April 2026. But after the Shenzhou XX astronauts used the Shenzhou XXI vehicle for their return to Earth, Shenzhou XXII is now required as a standby crew ship.

Tiny cracks were discovered on the viewport window of the Shenzhou XX return capsule, likely caused by an external impact from space debris.

The three Shenzhou XX astronauts landed safely on Nov 14 using the Shenzhou XXI spacecraft, returning nine days later than planned. Their 204 days in orbit set a new record for the longest in-orbit stay by Chinese astronauts.

Their safe and rapid return after the unexpected debris incident was made possible by preplanned contingency measures, including maintaining a rocket and crew spacecraft on standby. If an in-orbit crew ship encounters a problem, the backup rocket can be launched after about nine days of preparation to deliver a replacement vehicle to Tiangong.