China’s three-man Shenzhou 12 crew floated into their return craft and undocked from the Tiangong space station Wednesday, heading for landing in remote northwestern China to close out a three-month mission, the longest human flight to date in the country’s space program.
As the Shenzhou 12 spacecraft departed the space station, a Chinese ground teams rolled an unpiloted cargo ship to its launch pad at the Wenchang launch base on Hainan Island, China’s southernmost province, for liftoff Monday on a resupply flight to the Tiangong complex.
The Shenzhou 12 crew undocked from Tiangong at 8:56 p.m. EDT Wednesday (0056 GMT Thursday) and backed away from the space station. The spacecraft performed a “radial rendezvous” test, a circumnavigation maneuver to fly the ship from a position in front of the space station to a point below the complex.
The test demonstrated an approach to a different Tiangong docking port, that will be used by future missions to link up with the space station, according to the China Manned Space Agency.
Shenzhou 12 halted its radial approach before docking, as planned, then flew away from the station as the three-man crew readied for re-entry and a parachute-assisted landing Friday.
Chinese officials have not officially announced the scheduled landing time, but Chinese authorities released an airspace warning notice for the landing zone between 1:14 a.m. and 1:44 a.m. EDT (0514-0544 GMT) Friday. The landing window opens at 1:14 p.m. Beijing time.
The return zone in Inner Mongolia region, known as Dongfeng, is a new location for Shenzhou landings. Previous Shenzhou missions parachuted into a different part of Inner Mongolia known as Siziwang Banner.
Nie Haisheng, commander of the Shenzhou 12 mission, is wrapping up his third flight into orbit. Crewmate Liu Boming is in the home stretch of his second space mission. First-time space flier Tang Hongbo rounds out the crew.
Shenzhou 12 is the seventh crewed spaceflight in China’s space program. The mission broke the record for the longest-duration Chinese human spaceflight, exceeding Shenzhou 11 mission’s 32 days in orbit in 2016.
Shenzhou 12 launched June 17 on top of a Chinese Long March 2F rocket from the Jiuquan space center in the Gobi Desert, a barren region in northwestern China. The craft docked with the Tiangong space station about six hours later, then the astronauts opened hatches to become the first crew to enter the new Chinese space lab.
The first element of the Tiangong space station launched in April. The Tianhe core module contains a regenerative lift support system, which produces breathing oxygen through electrolysis and recycles urine to make drinking water.
The Tianhe module also has astronaut living quarters, medical equipment, a command and control element, and an airlock and exterior handrails for spacewalks. There are three sleeping berths — one for each astronaut — and one toilet on the Tianhe core module, Chinese officials said.
The core module of the Chinese space station also has a treadmill and a stationary bicycle for astronauts to get some exercise.
A resupply spacecraft named Tianzhou 2 launched in May and docked with the Tianhe module, pre-positioning supplies and provisions to support the Shenzhou 12 crew once they arrived in June.
During their three months on Tiangong, the Shenzhou 12 astronauts completed two spacewalks July 4 and Aug. 20 totaling more than 12 hours. The astronauts also tested the space station’s robotic arm and performed science experiments, according to Chinese state media.
After the return of Shenzhou 12, Chinese officials plan to launch the Tianzhou 3 cargo ship to the Tiangong space station Monday on a Long March 7 rocket from the Wenchang space center at Hainan.
The Tianzhou 2 spacecraft, currently attached to the aft port of the Tianhe core module, is expected to soon detach and move to the forward port vacated by Shenzhou 12. Tianzhou 2 will perform in-orbit refueling tests there.
The next mission to launch to the space station after the Tianzhou cargo ship will be the next piloted Shenzhou flight, set for launch in October. The Shenzhou 13 crew mission is expected to last up to six months, breaking the Chinese spaceflight endurance record set by Shenzhou 12.
Email the author.
Follow Stephen Clark on Twitter: @StephenClark1.