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HELSINKI — China’s human spaceflight agency has delayed the scheduled return to Earth of a crewed Shenzhou spacecraft due to a suspected space debris impact.
“The Shenzhou-20 crewed spacecraft is suspected of being struck by a small piece of space debris, and impact analysis and risk assessment are underway,” the China Manned Space Engineering Office (CMSEO) statement Nov. 5 read. “To ensure the safety and health of the astronauts and the complete success of the mission, it has been decided that the Shenzhou-20 return mission, originally scheduled for Nov. 5, will be postponed.”
CMSEO did not specify the location of the suspected strike, the extent of any damage, or the data that indicated an impact. No potential dates were noted for a return to Earth.
The Shenzhou-20 spacecraft launched April 24, carrying three astronauts—commander Chen Dong and crewmates Chen Zhongrui and Wang Jie—to the Tiangong space station. The spacecraft docked at the radial port of Tiangong’s Tianhe core module. The crew have completed their six-month-long mission in orbit, and had handed over control of the space station to the newly-arrived Shenzhou-21 crew Nov. 4.
Shenzhou-21, carrying commander Zhang Lu and crewmates Zhang Hongzhang and Wu Fei, arrived at the station Oct. 31 following launch 3.5 hours earlier atop of a Long March 2f rocket from Jiuquan spaceport.
Space debris is a growing concern in low Earth orbit and both the International Space Station and Tiangong have needed to maneuver to avoid potential collisions with debris. Some pieces are too small to track using ground-based As objects in low Earth orbit travel at around 8 kilometers per second (though relative velocities of two objects vary) even the impact of a small piece of debris is a highly energetic event, which could damage vital heat shielding or systems required for a safe reentry into Earth’s atmosphere.
Checks on the Shenzhou-20 spacecraft could include telemetry and leak tests, verifying guidance and propulsion systems, and screening for impacts in accelerometer and acoustic sensor data. A key concern would be potential damage to the spacecraft’s thermal protection system or parachute deployment structures, both critical for safe atmospheric reentry and landing.
Tiangong features a 10-meter-long robotic arm, capable of crawling, and a smaller, more precise arm. These could be employed to position cameras and provide closeup imagery of a potential impact.
Crews may be able to conduct an extravehicular activity (EVA) to assess the situation. Tiangong crews have recently added debris shields during a number of EVAs; the same procedures, tools, and arm support can be adapted for a Shenzhou inspection.
Earlier stated CMSEO redundancy and contingency options include the Shenzhou-20 crew using the recently-arrived Shenzhou-21 spacecraft to return to Earth. China keeps another Shenzhou spacecraft and Long March 2F in a state of near readiness at Jiuquan for emergency situations, and these could be readied for launch in 8.5 days.
Jiuquan Satellite Launch Center test facilities have two compartments, with one for a spacecraft-rocket combination in the east and one for a backup stack in the west. This allows the backup to be rapidly integrated into test and launch procedures.
The postponement of the return of Shenzhou-20 is the first such issue due to a potential space debris impact. The return of Shenzhou-19, April 30, had been delayed by one day due to poor weather at the Dongfeng landing area in Inner Mongolia Autonomous Region, near Jiuquan spaceport.
Tiangong typically hosts crews of three astronauts for stays of six months. The orbital outpost hosts six astronauts for a few days during handovers between incoming and outgoing crews. The six Shenzhou-20 and 21 astronauts enjoyed barbeque together in the past few days, using a new, smoke-free “space oven” Chinese media report.
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