Chinanews.com, Beijing, May 30, title: "Harmony in harmony": Tianzhou 2 and Tianhe core capsule staged a "space kiss"
Author Guo Chaokai Xue Yingmin
At 5:01 on May 30, about 8 hours after the successful launch, the Tianzhou-2 cargo spacecraft completed a fully autonomous and rapid rendezvous and docking with the Tianhe core module of the Chinese space station, and staged the "romantic kiss" again in space.
Space rendezvous and docking is one of the three basic technologies for manned space activities. It is a prerequisite for the realization of on-orbit services such as the assembly, recovery, replenishment, maintenance, astronaut exchange and rescue of space stations and space transportation systems, with high complexity and accuracy. High degree of accuracy, high autonomy requirements, and high security requirements.
To master this technology, Chinese astronauts have worked hard for nearly 30 years.
"Ten Thousand Miles of Needle" reappearance
The rendezvous and docking between Tianzhou-2 and Tianhe core module is the second rapid rendezvous and docking conducted by China in orbit, and the "Ten Thousand Mile Needle" technology reproduces space.
Compared with the rendezvous and docking of Tianzhou-1 and Tiangong-2 in 2017, this rendezvous and docking has achieved a new technological upgrade.
Compared with Tianzhou-1, Tianzhou-2 has added the "full-phase and fully autonomous rendezvous and docking program."
Experts from the Fifth Academy of China Aerospace Science and Technology Corporation explained that “full phase” means that no matter the relative position of the target aircraft and the space station when it enters orbit, there are 1/4 or half circles, even if the whole circle is complete, the “Tianzhou” can reach the fastest speed. Or the docking can be realized at the specified time point, instead of specially selecting the launch time of the spacecraft according to the location of the space station, the all-weather launch is truly realized.
"Full autonomy" means that from the spacecraft's orbiting to the successful rendezvous and docking, the whole process does not require manual intervention, and the on-board controller is independently planned.
Tianzhou-1 needs manual assistance to guide the spacecraft to a certain distance from Tiangong-2 in the long-distance segment, and then the spacecraft autonomously completes the close-range rendezvous and docking.
The Tianzhou-2 has added long-distance autonomous guidance, and the spacecraft can use the position information of Beidou navigation to realize long-distance fully autonomous navigation calculation and guidance and control.
In other words, when the Tianzhou cargo spacecraft visits the space station in the future, people will only be responsible for monitoring during this process, and the entire rendezvous and docking process will be completed by Tianzhou completely autonomously.
Suitable for both automatic control and manual control
Manual rendezvous and docking and automatic rendezvous and docking are the "left and right hands" of the space rendezvous and docking system. They are mutual backups and are an important guarantee for system reliability.
Therefore, the Shenzhou manned spacecraft has designed relatively independent systems for the two systems according to different logics from the beginning of its development.
Although Tianzhou-2 is a cargo spacecraft, it is also equipped with a manual control system. In the final translation and close section of the rendezvous and docking of the cargo spacecraft and the space station, manual control is one of the important control methods. It has the ability to support the astronauts in the space station to carry out manual remote control. The operation realizes forward or backward rendezvous and docking or the ability to withdraw and evacuate.
Once the automatic rendezvous and docking mode fails, the control system can be switched to manual remote operation mode, and the astronauts on the space station can use "teleoperation" to "drive" the spacecraft by remote control, so that the cargo spacecraft can evade the space station or safely and accurately. Docking with the space station.
In order to ensure the overall reliability of the system, the automatic control and manual control systems of the Tianzhou cargo spacecraft have realized mutual fault isolation by designing different information interfaces, but can realize reliable mode switching when necessary.
Sharpen a sword in the past thirty years
In order to build China's own space station as soon as possible, before the establishment of China's manned space project, the 502 scientific researchers of the Fifth Academy of China Aerospace Science and Technology Corporation aimed at the rendezvous and docking technology necessary for the construction of the space station and began to tackle key problems.
As of November 2011, Shenzhou-8 successfully completed two automatic rendezvous and docking with Tiangong-1.
In June 2012, Shenzhou 9 successfully achieved manual rendezvous and docking with Tiangong-1 under the control of astronaut Liu Wang, marking China's breakthrough in a series of key technologies such as relative navigation, guidance, control, and rendezvous and docking relative measurement sensors. Become the third country in the world to independently master rendezvous and docking.
In 2016, as a necessary related technology for rendezvous and docking, the orbiting technology was verified in the Shenzhou 10 mission.
In 2017, the Tianzhou-1 and Tiangong-2 rapid rendezvous and docking on-orbit tests were successfully completed, making China the third country in the world to master the near-Earth rapid rendezvous and docking.
After that, the R&D team spent several years perfecting the rendezvous and docking technology in terms of autonomy and reliability. By the time Tianzhou 2 docked with the Tianhe core cabin, the three-generation R&D personnel of 502 institutes had been fighting for nearly 30 years.
With the first successful "space hand-in-hand" between Tianzhou-2 and Tianhe core module, China's space rendezvous and docking technology has also ushered in a new historical stage.
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