This view shows a Shenzhou spacecraft leaving the Tiangong space station in 2023.
Credit: China Human Space Mission Agency
Spacecraft exchange in low Earth orbit
With their original spacecraft deemed unsafe, Chen and his crewmates returned to Earth aboard the new Shenzhou 21 craft that was launched and arrived at Tiangong Station on October 31.—Zhang Lu, Wu Fei and Zhang Hongzhang– staying aboard the nearly 100-ton space station with only the damaged Shenzhou 20 craft available to take them home.
China’s Shenzhou line of spacecraft not only provides transportation to and from low Earth orbit, but also serves as lifeboats to evacuate astronauts from China’s space station in the event of an in-flight emergency, such as a major failure or medical crisis. They fulfill the same role as the Russian Soyuz and SpaceX Crew Dragon vehicles flying to and from the International Space Station.
Another Shenzhou spacecraft, Shenzhou 22, “will be launched at a later date,” the China Human Space Mission Agency said in a statement. Shenzhou 20 will remain in orbit to “continue relevant experiments.” The Tiangong laboratory is designed to accommodate crews of six for short periods only, with longer stays of three astronauts.
Officials have not revealed when Shenzhou 22 might launch, but Chinese officials typically have a Long March rocket and a Shenzhou spacecraft waiting for a quick launch if needed. Instead of astronauts, Shenzhou 22 will carry fresh food and equipment to support the three-man crew of Tiangong Station.
China’s official Xinhua news agency called Friday’s return “the first successful implementation of an alternative return procedure in the history of the country’s space station program.”
Unstable return schedules and damaged spacecraft at Tiangong Station are reminders of the risks associated with space junk, particularly tiny fragments of debris that escape detection by telescopes and tracking radars. A tiny space debris moving at several kilometers per second can have a huge impact. Crews from the Tiangong Outpost have ventured outside the station several times over the past several years to install space debris protection to protect the outpost.
Astronaut Tim Peake took this photo of a cracked window on the International Space Station in 2016. The 7-millimeter (quarter-inch) divot on the quadruple-glazed window was gouged by the impact of space debris no larger than a few thousandths of a millimeter in diameter. The damage poses no risk to the station.
Credit: ESA/NASA
Shortly after landing on Friday, ground crews helped the Shenzhou astronauts out of their landing module. All three appeared healthy and in good spirits after completing the longest crew mission in China’s space program.
“Space exploration has never been easy for mankind,” said Chen Dong, mission commander, according to Chinese state media.
“This mission was a real test and we are proud to have completed it,” Chen said shortly after landing. “China’s space program has stood the test, with all teams performing exceptionally well… This experience has left us with a deep impression that the safety of astronauts is truly a priority.”
