“The Shenzhou-20 manned spacecraft’s return capsule window glass had developed a minor crack, most likely caused by an external impact from space debris, thus failing to meet the requirements for a safe crewed return.”
Hours before the Shenzhou-20 crew was scheduled to undock from China’s Tiangong station on November 5, engineers discovered a cracked window from suspected debris impact. The three astronauts instead returned on the Shenzhou-21 spacecraft nine days later, becoming the first Chinese crew to spend over 200 days in space. China then launched an uncrewed Shenzhou-22 six months ahead of schedule to restore a lifeboat for the station crew who were left temporarily without one.