Three more Chinese astronauts are now stranded in space following successful rescue of their colleagues

The Shenzhou-21 crew launched to the Tiangong space station on Oct. 31. The capsule they arrived on has since returned to Earth without them, leaving them temporarily marooned. | Credit: VCG/VCG via Getty Images

Three Chinese Astronauts Marooned in Space Amid Concerns Over Tiangong Protocols

Three more Chinese astronauts, or taikonauts, are now stranded aboard China’s Tiangong space station, following the safe return of their previously marooned colleagues. Experts say the situation highlights potential weaknesses in China’s space protocols that could put astronauts at unnecessary risk.

The Shenzhou-21 crew has been temporarily marooned on China’s Tiangong space station. This photo shows Zhang Lu (right), Wu Fei (center) and Zhang Hongzhang (left)before they launched into space on Oct. 31. . | Credit: HECTOR RETAMAL/AFP via Getty Images

The stranded crew — Zhang Lu, Wu Fei, and Zhang Hongzhang of the Shenzhou-21 mission — have been aboard Tiangong since October 31, shortly after their launch aboard a Long March 2F rocket. Their mission was to relieve the Shenzhou-20 crew — Wang Jie, Chen Zhongrui, and Chen Dong — who were originally scheduled to return to Earth on November 5.

After a successful handover, the Shenzhou-20 crew’s return was abruptly delayed when a suspected piece of space debris struck their return capsule. Tests revealed a crack in the capsule’s viewing port, prompting the crew to use the return vehicle originally assigned to Shenzhou-21. They successfully returned to Earth on November 14, completing a record-setting 204-day single spaceflight for taikonauts.

The stranded Shenzhou-20 crew returned to Earth on Nov. 14, touching down in the Gobi Desert. This photo shows the crew’s commander Chen Dong being escorted away from the Shenzou-21 return capsule. | Credit: Jiang Jurong/VCG via Getty Images

While the safe return of the Shenzhou-20 crew was widely celebrated, it leaves the Shenzhou-21 crew without an immediate way to return to Earth, Live Science’s sister site Space.com reported.

Unconfirmed reports suggest the China Manned Space Agency (CMSA) may launch a replacement return capsule, Shenzhou-22, to Tiangong as soon as November 24, according to Space News. In the meantime, any potential emergency — such as another collision with space debris — could pose serious risks to the Shenzhou-21 crew. “I’m very glad that they got home, but it is a bit disconcerting that the replacement crew apparently does not have a vehicle to come back to Earth,” said Victoria Samson, chief director of space security and stability at the Secure World Foundation, to Scientific American.

Once the new capsule reaches Tiangong, the damaged Shenzhou-20 capsule will likely be detached and deorbited into the Pacific Ocean, Reuters reported. The Shenzhou-21 crew is still expected to complete their six-month mission as planned.

CMSA has not explained why the Shenzhou-20 crew returned before a new capsule was available. Some experts speculate that Tiangong — about one-fifth the size of the International Space Station — may not be able to safely accommodate all six taikonauts at once, although CMSA has previously dismissed this concern. In emergencies, the crew could potentially use the damaged Shenzhou-20 capsule to return to Earth, as long as the crack does not compromise the main return module, which houses the parachute-assisted reentry system, Ars Technica notes.

China’s limited disclosure about its missions and spacecraft means the full reasoning behind these decisions may never be publicly known.

The current situation echoes previous “strandings” aboard the ISS, such as NASA astronauts Suni Williams and Butch Wilmore, who were delayed for nine months, and Frank Rubio, who spent over a year in space. Unlike those incidents, however, the ISS crews always had safe, docked return capsules available — a luxury the Shenzhou-21 crew currently lacks.

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