HELSINKI — A pair of Chinese astronauts embarked on an extravehicular activity outside the Tiangong space station Friday, as the crew approaches the end of their six-month-long stay in orbit.
Astronauts Cai Xuzhe and Song Lingdong returned to the Wentian science module at 8:50 a.m. Eastern (1250 UTC) March 21, completing their seven-hour extravehicular activity (EVA). Cai initially opened the Wentian hatch at 1:45 a.m. (0545 UT), according to China’s human spaceflight agency, CMSA.
Cai and Song installed space debris protective shielding to the outside of the Wentian module, completing the deployment of shielding carried out across a series of missions and EVAs. The pair also installed extravehicular auxiliary facilities and conducted inspection of extravehicular equipment and systems. The latter task included Cai riding Tiangong’s robotic arm to the specific points on the space station’s exterior, conducting photographic inspections.
Wang Haoze, China’s first woman space engineer and the third member of the crew, assisted operations from inside the Tiangong space station, as she had done for the mission’s previous two EVAs. The first EVA, in December 2024, set an apparent world record for spacewalk duration at 9 hours 6 minutes. Cai Xuzhe has now completed five EVAs, more than any other Chinese astronaut.
“The astronauts performed exceptionally well during the extravehicular mission. First, all of our operations were successful on the first attempt, and the alignment and installation of devices were very precise. In fact, the astronauts completed the tasks even faster than we had anticipated,” Wang Yanlei, a staff member with the Beijing-based China Astronaut Research and Training Center, told China Central Television (CCTV) following the EVA.
“The coordination between the astronauts, as well as between the space station and the ground team, was seamless,” Wang said.
The trio now have just over a month remaining aboard Tiangong, according to CMSA, having arrived at Tiangong Oct. 29 last year. Over the past five months, the crew has conducted a variety of space science experiments and technology demonstrations, including fruit fly cultivation, experiments on protein crystallization, and studies on five types of cells.
Mission activities included materials science, carrying out a number of metal and non-metal experiments in Tiangong’s containerless experiment and high temperature scientific experiment cabinets.
“By leveraging the different experimental conditions of China’s space station and the International Space Station, we conduct scientific research in related fields in a complementary manner, enabling deeper and more extensive space exploration,” Wang Yifeng, an engineer at the Technology and Engineering Centre for Space Utilization, Chinese Academy of Sciences, told CCTV.
The Shenzhou-19 mission has also established a new health assessment system for astronauts in a microgravity environment. The system tracks key physiological and psychological indicators, including cardiac health, bone density, muscle mass and emotional well-being. The system also integrates traditional Chinese and Western medicine.
The crew have also been assisted by Xiao Hang (“Little Space”), a small AI robot equipped with human-robot interaction software to support mission operations.
Crews and backups for the following Shenzhou-20 and -21 missions—which will be China’s 15th and 16th crewed spaceflight missions overall—have been selected, according to Chinese space officials. Neither the identities of the crews nor the timing of the missions have been announced. Each mission will last around six months. During crew handovers, Tiangong briefly hosts six astronauts for several days.
The Long March 2F rocket to launch the Shenzhou-21 mission in the second half of 2025 set off via train for Jiuquan Satellite Launch Centre, northwest China, March 18, after assembly and testing by the China Academy of Launch Vehicle Technology (CALT) in Beijing. The rocket will be kept in a near-ready state to enable a rapid-response rescue launch if needed. The Long March 2F (Y20) and Shenzhou-20 spacecraft have been on standby for an emergency launch since the launch of Shenzhou-19, as a matter of standard practice.
