HELSINKI \u2014 China\u2019s damaged Shenzhou-20 spacecraft returned safely to Earth after on-orbit internal repairs, concluding the country\u2019s first human spaceflight emergency triggered by a suspected debris impact.<\/p>\n
Shenzhou-20 landed at 8:24 p.m. Eastern, Jan. 18 (0134 UTC, Jan. 19) at the Dongfeng landing zone near Jiuquan Satellite launch Center in the Gobi Desert, northwest China, having undocked from Tiangong space station at 1623 UTC Jan. 18.\u00a0<\/p>\n
Images showed the return capsule upright on the ground but the viewport window, damaged by suspected on-orbit debris or a micrometeoroid impact, was covered up after landing. The Shenzhou-20 return module\u2019s exterior was generally normal, and the items inside were in good condition, according<\/a> to China\u2019s human spaceflight agency, CMSEO.<\/p>\n The spacecraft landed two and a half months later than planned after being assessed unsafe to deliver its crew to Earth due to discovery of a small, penetrating triangular crack in the outer layer of a three-layer viewport window in the crew\u2019s return module. The discovery of the crack<\/a> triggered China\u2019s first on-orbit human spaceflight crisis and emergency response, seeing a crew transfer<\/a> to a different spacecraft to return to Earth, the launch<\/a> of a backup for crew still aboard Tiangong, and an acceleration in production of spacecraft and launch vehicles on the ground to fill an emergency launch gap<\/a>.<\/p>\n Shenzhou-20 spent 270 days in orbit due to the crisis, whereas most Shenzhou spacecraft spend around 180 days in orbit during the Tiangong space station operational phase. The spacecraft also returned to Earth with Feitian EVA spacesuit B. The suit had supported 11 Chinese astronauts across eight crewed missions, enabling 20 successful EVAs to be conducted since arriving at the then-under-construction Tiangong in July 2021.<\/p>\n The Shenzhou-20 astronauts, who returned to Earth using the Shenzhou-21 spacecraft that had days earlier delivered the new Shenzhou-21 crew to Tiangong in early November, appeared<\/a> at a press conference Jan. 16, 63 days after their return. It was confirmed that the astronauts discovered the triangular crack in Shenzhou-20\u2019s return module viewport window during a final pre-return check. Commander Chen Dong sent images to Earth, triggering a cascading series of crew transfer and launch decisions.<\/p>\n \u201cWe took photographs right away and recorded the situation, and immediately transmitted the data back to the ground,\u201d Chen said. \u201cBased on my visual observation, I initially judged that the crack was on the outermost layer of the spacecraft window. The crack had penetrated that outer layer, but it did not affect the safety of our continued stay in orbit. Afterwards, the two crews, six astronauts in total, carefully observed and discussed the condition of the window together, and fully cooperated with the ground teams to carry out rechecks and confirmation,\u201d said Chen.<\/p>\n Teams on the ground delayed the return of Shenzhou-20, seeing the use of Shenzhou-21 to deliver the Shenzhou-20 astronauts back to Earth, and resulting in the uncrewed Shenzhou-22 being launched to Tiangong, arriving Nov. 25<\/a>, to provide a lifeboat for the Shenzhou-21 crew.\u00a0<\/p>\n Shenzhou-21 mission commander Zhang Lu and crewmate Wu Fei conducted an extravehicular activity<\/a> Dec. 9 (UTC), inspecting the damaged window from outside the spacecraft. The astronauts applied a patch, delivered in Shenzhou-22, to the window from the inside, designed to improve the spacecraft\u2019s heat protection and sealing capabilities during reentry.<\/p>\n An external repair was deemed impractical. Shao Limin of the China Aerospace Science and Technology Corporation (CASC), the state-owned space contractor, stated<\/a> that while large and medium-sized pieces of debris could be avoided, the strength of the spacecraft\u2019s window structure would be needed to handle small, undetectable pieces, with improvements to be made in the future.<\/p>\n