By 
September 16th, 2021
Rollout of supply ship. Credit: CCTV/Inside Outer Space screengrab
China’s next milestone in constructing the country’s space station has rolled out to the launch pad at the Wenchang Spacecraft Launch Site in south China’s Hainan Province.
A Long March-7 booster was vertically transported to its liftoff location on Thursday. The launcher is topped by the uncrewed Tianzhou-3 cargo ship. The hardware will undergo final tests before the planned launch to China’s space station in the coming days.
Return to Earth
Meanwhile, the now in Earth orbit Shenzhou-12 crew is returning to Earth, tomorrow, on September 17. Earlier in the day, the China Manned Space Engineering Office announced the spacecraft had successfully separated from China’s space station.
Credit: CCTV/Inside Outer Space screengrab
After departure from the Tianhe core station module, the Shenzhou-12 spacecraft crew is performing orbiting and radial rendezvous tests with the space station. Doing so, they will verify radial rendezvous technology, a technique for subsequent piloted missions.
Credit: CCTV/Inside Outer Space screengrab
The Shenzhou-12 trio of taikonauts will parachute into the Dongfeng landing site in north China’s Inner Mongolia Autonomous Region. A search and rescue team from China’s Jiuquan Satellite Launch Center in the Gobi Desert recently conducted drills at the landing site.
New record…for China
The Shenzhou-12 crew has worked and lived in the space station for 90 days, setting a new record for Chinese astronauts’ in-orbit stay for a single mission.
Credit: CCTV/Inside Outer Space screengrab
Launched on June 17, the Shenzhou-12 trio entered the space station’s core module on the same day.
The China space station, orbiting the Earth at a height of about 250 miles (400 kilometers), is still under construction. Eight more missions, including three piloted flights, are still being arranged to complete the space station by late next year.
Radial rendezvous
China’s Shenzhou-12 spaceship crew is conducting radial rendezvous with the Tianhe core module combination in orbit for the first time on Thursday.
Credit: CCTV/Inside Outer Space screengrab
Different from the forward and rearwards rendezvous China had done in the past on its spacecraft, the radial rendezvous is a much more difficult task to achieve in terms of the technical level, said Xie Yongchun, director of the Technology Committee in China Academy of Space Technology (CAST)’s 502 Research Institute.
“The forward and rearward rendezvous are conducted on a 200-meter contact point. It is a stable point, which means it can be kept unmoved if the engines on the spacecraft are off. But the radial rendezvous is something different,” Xie told China Central Television (CCTV). “Due to the kinetic characteristics of the orbit, the spacecraft will not be able to stay there stably in space. Therefore, we will keep conducting orbit control of the spacecraft.”
Attitude maneuver
During the radial rendezvous process, Shenzhou-12 has to adjust its attitude constantly. How to keep the attitude of the spacecraft stable and how to keep its interface with the core module accurate are difficult problems faced by aerospace scientists.
“We must ensure that the sensor information will not be lost in the process of attitude maneuver, in a dynamic process. This is more difficult to achieve than when the sensor is in a stable status. We have to solve this problem by improving the measurement accuracy and stability of the sensor in dynamic conditions,” Xie said.
The radial rendezvous test on Shenzhou-12 this time will be conducted without the docking process, in efforts to prove whether or not the sensor on the spacecraft, which can be viewed as the spacecraft’s “eyes”, can play its role effectively.
Shenzhou-12 crew members prepare to depart core module.
Credit: CCTV/Inside Outer Space screengrab
“It will have a great impact on our measurement accuracy if we can’t see the mark point clearly. Another thing is, the lighting conditions might be different during the process of the radial rendezvous, very different from the forward and rearward rendezvous. Since the space station is in orbit, the lighting conditions may change anytime during the rendezvous process. This will affect the reflection characteristics of the mark. So we have to conduct trial operations beforehand,” Xie said.
China’s space station is projected to be completed in late 2022.
Credit: CAST
Launch schedule
The soon to launch Shenzhou-13 piloted spaceship will dock with the Tianhe core module, starting a three-person, six-month stay in orbit, according to the China Manned Space Agency (CMSA).
After the five launch missions this year, China plans to have six more missions in 2022, including the launch of the Wentian and Mengtian lab modules, two cargo spacecraft and two crewed spaceships to complete the construction of the space station.
New videos
Go to these newly released videos for a view of the rollout of the Tianzhou-3 supply ship, radial rendezvous, the Shenzhou-12 crew departing the core module, and preparations underway for recovery of the returning trio of Taikonauts.
Long March-7 Y4 ready to launch Tianzhou-3 at:
Shenzhou-12 radial rendezvous test explained at:
China’s Shenzhou-12 Manned Spaceship Undocks from Space Station Core Module for Return Trip at:
Ground Search Team Ready for Return of Shenzhou-12 Crew to Dongfeng Landing Site at:
Posted in Space News
