Shenzhou-21 Mission Extended at Tiangong Space Station

The crew of China's Shenzhou-21 mission has had its stay aboard the Tiangong space station extended by approximately one month. The extension is intended to further validate technologies for long-duration human spaceflight and to utilize supplies delivered by an uncrewed cargo spacecraft.

The decision, announced by the China Manned Space Agency (CMSA), follows the crew's completion of a third extravehicular activity (EVA), or spacewalk, in mid-April.

Mission Timeline and Crew

The three-person crew—Commander Zhang Lu, spaceflight engineer Wu Fei, and payload specialist Zhang Hongzhang—launched from the Jiuquan Satellite Launch Centre on October 31, 2023, aboard a Long March-2F rocket. They arrived at the Tiangong space station on November 1, 2023, initiating China's 16th crewed spaceflight.

The original mission duration was scheduled for six months, with an expected conclusion around April 2024. Following the extension, the crew is now scheduled to return to Earth in early June.

Spacewalk Activities

The Shenzhou-21 crew has conducted multiple extravehicular activities during their mission:

• First EVA: December 9, 2023.
• Second EVA: Completed on a Monday in late 2023 or early 2024, lasting approximately seven hours.
• Third EVA: Completed on April 17, 2024. Commander Zhang Lu and engineer Wu Fei spent about five and a half hours outside the station, returning to the Wentian science module at 1:36 a.m. Beijing Time on April 19. Specialist Zhang Hongzhang provided internal support.

Common tasks during these spacewalks included installing space debris protection devices on the station and inspecting extravehicular equipment and facilities. The astronauts were assisted by the space station's robotic arm and ground controllers.

The April spacewalk was reported to be the 27th conducted by Chinese astronauts and the seventh for Commander Zhang Lu, giving him the highest number of spacewalks among Chinese astronauts.

Mission Activities and Extension Rationale

Throughout their stay, the crew has engaged in a range of operational and scientific work:

• Conducting routine equipment inspection, maintenance, and cargo management.
• Performing in-orbit environmental monitoring and crew health management.
• Completing training drills for emergency scenarios.
• Carrying out scientific experiments in fields such as space life science, human physiology, microgravity physics, and new space technologies.

The CMSA stated the one-month mission extension was decided after analysis and assessment. The agency provided two stated reasons for the adjustment:

1. To further verify technologies supporting long-term human stays in orbit.
2. To make full use of materials delivered by the Shenzhou-22 cargo spacecraft, which was launched on an uncrewed resupply mission in late November 2023.

For the remainder of their extended mission, the crew is planned to continue ongoing scientific experiments and technical tests.