Chinese astronauts finally reveal why spacecraft left them ‘stranded’ for 437 days in space

Crew members of China's Shenzhou-20 mission recently detailed their reactions upon finding cracks in their spacecraft's viewport during the nation's first spaceflight emergency.

Taikonauts from the fated Shenzhou-20 mission have described what happened when they discovered cracks on their spacecraft as they prepared to depart China's Tiangong space station last year.

Chinese astronauts revealed the major reason behind the mishap:

Astronauts have finally described what happened when they were nearly stranded in space last year after a suspected piece of space junk struck their return capsule.

Chinese astronauts revealed that several structural cracks had extended completely through components of their spacecraft, raising safety concerns during the mission. 

Engineers monitored the damage closely, implemented precautionary measures, and ensured the crew’s safe return despite the unexpected technical challenges.

New Details:

During a routine check, the astronauts spotted something unusual, beginning what has since been described as China's first spaceflight emergency.

Chen Dong, Chen Zhongrui and Wang Jie, the crew of the ill-fated Shenzhou-20 mission, were preparing to leave China's Tiangong space station and return to Earth on November 5, 2025.

Commander Chen Dong was carrying out final checks on the return capsule when he noticed a triangular mark in the spacecraft's viewpoint window, according to a detailed interview with the crew by Chinese state media, reported by Live Science and Space.

Chen said in the interview, aired by China Central Television CCTV, "My first thought was whether a small leaf had somehow stuck to the outside of the window."

"But then I quickly realized that couldn't happen because we were in space. How could there possibly be a fallen leaf there?"

Chen determined that the leaf-shaped mark was the result of cracks in the window, some of which he said "had penetrated through." 

His crew then worked with the Shenzhou-21 relief crew and ground teams on Earth to check and confirm the condition of the window.

The taikonauts, or Chinese astronauts, have previously described taking a methodical approach to what could have been a perilous event.

Longest time in space:

The taikonauts arrived at the Tiangong, Mandarin for "heavenly palace," space station on April 24, 2025.

Their original departure date of Nov. 5 was pushed back after the crack was discovered, but they were able to travel home 9 days later in the Shenzhou-21 spacecraft that had delivered their relief crew.

Moreover, the three taikonauts safely touched down in northern China's Inner Mongolia Autonomous Region on Nov. 14.

The crew spent 204 days in orbit, which was a record for a taikonaut crew, though far from the record for the longest time humans have spent in space—437 days.

Astronauts revealed worst-case scenarios:

They informed that the quantity of space junk in Earth's orbit is increasing, which could create worse situations in the future.

The junk, which includes things like rocket boosters and other discarded space travel objects, has the potential to collide with uncrewed and crewed spacecraft and thus puts astronauts at risk.

Various methods have been proposed to deal with the growing space debris problem, including the development of sci-fi-inspired tractor beams and junk-capturing spacecraft. 

But so far, no potential solutions are ready to be deployed at scale.