The return of three Chinese astronauts from a six-month mission aboard the Tiangong space station was abruptly postponed this week after their Shenzhou-20 spacecraft was suspected of being struck by a small piece of orbital debris. The China Manned Space Agency (CMSA) announced the delay on Wednesday, November 5, 2025, prioritizing crew safety while engineers conduct a thorough risk assessment of the vehicle. The three astronauts are safe and remain on the station with their recently arrived replacements.
This unprecedented incident for China’s rapidly advancing space program highlights the escalating threat that human-made space junk poses to all orbital operations. Astronauts Chen Dong, Chen Zhongrui, and Wang Jie were scheduled to land at the Dongfeng site in Inner Mongolia on Wednesday, but ground control scrubbed the departure just a day after the crew held a formal handover ceremony with the newly arrived Shenzhou-21 mission. With the Shenzhou-20 capsule now under intense scrutiny, no new timeline for the crew’s return has been provided, leaving two full crews temporarily living and working together in orbit.
Mission Halted After Handover
The delay occurred at the final stage of a highly successful six-month tour of duty for the Shenzhou-20 crew. Having launched in April 2025, the astronauts had completed numerous scientific experiments and conducted four spacewalks to perform maintenance and install new hardware on the Tiangong station. Their replacements, the Shenzhou-21 crew, arrived safely at the station on Saturday, November 1, marking the beginning of a standard in-orbit crew rotation.
A formal handover ceremony took place on Tuesday, November 4, a routine procedure signifying the transfer of command. State media broadcasts showed Commander Chen Dong symbolically handing over the station’s hatch key to the incoming crew, stating, “We are about to return to Earth, and now I am handing over the hatch key that symbolizes the right to maintain operations on this Chinese space station to you.” All preparations appeared to be on track for a Wednesday landing. However, the subsequent announcement from the CMSA confirmed that the departure was on hold pending a critical evaluation of their ride home.
Intensive On-Orbit Investigation
Official Statements
In a brief but direct statement, the CMSA confirmed the reason for the delay. “The Shenzhou-20 manned spacecraft is suspected of being hit by a tiny piece of space debris, and an impact analysis and risk assessment are under way,” the agency announced. Officials emphasized that the postponement was a necessary precaution to ensure the crew’s “safety and health” but did not offer any specific details about when the suspected impact occurred, how it was detected, or the potential extent of the damage. The priority for engineers is a complete assessment of the Shenzhou-20 vehicle’s integrity before it is cleared for the fiery plunge through Earth’s atmosphere.
Contingency Measures
While the analysis continues, China’s space program has robust contingency plans. As a precautionary measure, a backup Long March-2F rocket and a Shenzhou spacecraft are always on standby at the Jiuquan Satellite Launch Center for potential emergency rescue missions. Another option, should the Shenzhou-20 be deemed unsafe for reentry, is the potential use of the newly arrived Shenzhou-21 spacecraft to return the crew. Such a scenario would mirror the 2022 incident involving a coolant leak on a Russian Soyuz capsule at the International Space Station, which required a replacement vehicle to be launched to bring the crew home safely after a lengthy delay.
The Ever-Present Danger of Space Junk
The Shenzhou-20 incident serves as a stark reminder of the growing hazard posed by orbital debris. Space junk encompasses a wide range of non-functional, human-made objects, including defunct satellites, discarded rocket stages, and countless fragments from past collisions and anti-satellite weapons tests. These objects travel at incredible speeds; in low Earth orbit, where the Tiangong station operates, velocities can reach 7.5 kilometers per second (about 17,500 miles per hour).
At such extreme velocities, even a minuscule fragment can inflict catastrophic damage. Experts have warned that a collision with an object just one centimeter in diameter can release energy equivalent to that of a hand grenade. Both the International Space Station and China’s Tiangong station are shielded against minor impacts, and the ISS has had to perform avoidance maneuvers many times in recent years to dodge known debris. This event marks the first time a Chinese-crewed mission has been directly delayed due to a suspected strike, bringing the issue to the forefront for the nation’s space ambitions.
Life Aboard a Crowded Station
For now, the six astronauts from the Shenzhou-20 and Shenzhou-21 missions are cohabiting the Tiangong space station. While the station is designed to support long-duration missions, hosting a double crew places additional demands on life support and logistical resources. Chinese state media had previously shared images of the combined crews enjoying meals together, including barbecued chicken wings prepared in an upgraded space oven, before the delay was announced.
The Shenzhou-20 crew, which includes Commander Chen Dong and operators Chen Zhongrui and Wang Jie, will now wait for clearance from ground control while their successors begin their own six-month mission. This unexpected extension of their time in orbit underscores the unpredictable nature of spaceflight and the critical importance of vehicle integrity for the safe return of any crew.
