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

In a brief statement released on Monday afternoon, the agency said that the propellant injection for the Long March 2F carrier rocket, which will lift the robotic spacecraft, has 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. However, as 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, rendering it unsafe for use.

The three Shenzhou XX astronauts landed safely on Nov 14 using the Shenzhou XXI spacecraft, returning nine days later than scheduled. 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 due to 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 preparations to deliver a replacement vehicle to Tiangong.

zhaolei@chinadaily.com.cn