China's Shenzhou 21 Astronauts Stranded on Tiangong Space Station

Three astronauts aboard China's Shenzhou 21 mission are currently stranded on the Tiangong space station following an incident that damaged their intended return vehicle, the Shenzhou 20. According to Ars Technica, the astronauts, Commander Chen Dong, Chen Zhongrui, and Wang Jie, wrapped up 204 days in orbit and returned to Earth aboard the Shenzhou 21 spacecraft on November 13, after their planned return on November 5 was postponed due to a space debris strike that left the Shenzhou 20 capsule with a cracked window. This incident forced the crew of Shenzhou 20 to use the Shenzhou 21 vessel instead, leaving their colleagues—Zhang Lu, Wu Fei, and Zhang Hongzhang—without a reliable means of returning home. The China Manned Space Agency confirmed that the Shenzhou 20 spacecraft was deemed unfit for safe return, as noted by Space.com, which reported that the spacecraft would remain in orbit for further experiments despite its damage.

The situation underscores significant challenges in crewed space missions, particularly concerning emergency protocols. Gizmodo highlights that the Chinese space agency has alternative safety measures, including the potential launch of an uncrewed Shenzhou 22 capsule to the station to facilitate a safe return for the stranded astronauts if necessary. However, the timeline for this launch remains unspecified, adding to the uncertainty surrounding the safety of the crew aboard Tiangong. The Shenzhou 21 astronauts are now living in a precarious situation, as they face the possibility of an extended stay without a lifeboat, a scenario that is quite different from the redundancy systems in place for astronauts aboard the International Space Station.

As reported by Space.com, the current crew is under a policy that keeps a Long March 2F rocket and Shenzhou spacecraft in a state of near readiness during crewed missions. This means that if an emergency arises, a new lifeboat could be launched to the station in as little as 8.5 days. However, the lack of a safe return option for the Shenzhou 21 crew does raise alarms about the reliability of the operations aboard Tiangong, especially considering the increasing risks posed by space debris. The collision that damaged the Shenzhou 20 spacecraft is a stark reminder of the hazards of space travel; in 2023 alone, Tiangong experienced a partial loss of power due to a separate debris strike, forcing astronauts to perform repairs in space. As the number of tracked space debris objects continues to rise, the need for enhanced protective measures and emergency protocols becomes increasingly critical for ensuring astronaut safety. This incident not only raises questions about the immediate safety of the Shenzhou 21 astronauts but also highlights broader concerns regarding the sustainability and safety of China's growing presence in low Earth orbit.