Source: Science and Technology Daily
◎ Reporters Cui Shuang, He Liang, Fu Yifei
The Shenzhou XIII manned spacecraft was successfully launched, and the era of long-term presence on the Chinese space station arrived.
According to the China Manned Space Engineering Office, at 9:50 a.m. on October 17, three astronauts, Zhai Zhigang, Wang Yaping, and Ye Guangfu, successfully opened the cargo hatch and smoothly entered the Tianzhou-3 cargo spacecraft. Next, they will also open the cargo hatch of the Tianzhou-2 cargo spacecraft and carry out cargo transshipment and other related work as planned.
At 0:23 on October 16, the Long March 2F Yao-13 carrier rocket carrying the Shenzhou 13 manned spacecraft was successfully launched at the Jiuquan Satellite Launch Center, successfully sending three astronauts into space.
At 9:58 on the same day, the three astronauts entered the Tianhe core module and began a 6-month on-orbit stay. They will carry out robotic arm operation, outgoing activities, cabin transfer and other work, and further verify a series of key technologies such as astronauts' long-term orbital residency and regeneration life protection.
The Shenzhou 13 mission is a decisive battle and a final battle in the key technical verification stage of the space station, and it is also a key battle in the process of space station orbit construction.
It will set a new record for Chinese space residency
According to the predetermined plan, the docking time of Shenzhou 13 will be extended from 3 months to 6 months of Shenzhou 12, and the long-term stay mission of the 180-day composite will be carried out, which will be the longest manned flight in China so far, and the long-term on-orbit station station astronauts will be assessed and verified for the first time.
According to Zheng Wei, deputy chief designer of the Shenzhou 13 manned spacecraft of the Fifth Academy of Aerospace Science and Technology Group (hereinafter referred to as the Fifth Academy), the Shenzhou 13 spacecraft is a three-cabin structure of the propulsion module, the return module and the orbital module, with a total length of about 9 meters and a total of 14 subsystems, which is the "boat of life" for astronauts to realize the round-trip between heaven and earth.
Gao Xu, deputy chief designer of the Shenzhou 13 manned spacecraft system of the Overall Design Department of the Fifth Academy, introduced that in order to adapt to the complex external heat flow conditions brought about by the complex configuration and attitude of the space station and meet the requirements of ultra-long "standby", the team made a special design for the return module, the thermal control scheme such as the propulsion engine and the storage tank, and the grid-connected power supply scheme of the ship station, so that the spacecraft has the adaptive supporting conditions for power supply and thermal environment protection.
In addition, the Tianzhou-3, which arrived earlier, carried living materials that could be used for long-term stays, providing sufficient "logistical support" for astronauts.
Successfully implemented the first radial rendezvous docking
Shenzhou 13 "hand in hand" Tianhe core module is the first radial rendezvous and docking implemented by China's manned spacecraft in space.
At 6:56 on October 16, the Shenzhou 13 manned spacecraft successfully docked at the radial port of the Tianhe core module using the autonomous rapid rendezvous and docking mode, and together with the previously docked Tianzhou-2 and Tianzhou-3 cargo spacecraft, it formed a four-cabin (ship) combination, and the entire rendezvous and docking process lasted about 6.5 hours.
Since Shenzhou 8, the five manned spacecraft have all docked axially, and the radial and axial angle is 90 degrees. Although the direction has only changed by 90 degrees, it is much more difficult. Gao Xu said that there are "three difficulties" in radial rendezvous and docking. The first is the "difficulty" of continuously controlling the attitude and orbit. The radial rendezvous has no stable stopover point, which requires continuous control of the attitude and orbit of the spacecraft, and the propellant consumption is large and the fault disposal is difficult. The second is that the attitude and relative position are "difficult" to determine. The Shenzhou manned spacecraft is equipped with a sensor, which is like the eyes of the spacecraft, by observing the stars and preset marker points, etc., to determine its flight attitude, relative position to the space station, etc. However, due to the fact that in the process of radial rendezvous, the spacecraft needs to maneuver from a large range of attitudes such as horizontal flight to vertical flight, which puts forward higher requirements for the "eye" to see the target and ensure that the "eye" will not be disturbed by complex light changes. Finally, the astronaut hand-controlled rendezvous mode is "difficult". In the process of radial rendezvous and docking, the most familiar reference datum of the earth is basically lost, the measurement and control conditions become worse, and the relative dynamic motion characteristics are different from the forward rendezvous, which increases the difficulty of the astronaut's operation in the hand-controlled rendezvous mode.
It is understood that the entire process of this radial rendezvous and docking is completed intelligently and autonomously by the spacecraft under the command of the guidance navigation and control (GNC) system.
In order to adapt to the different configurations of the space station assembly and the different docking states of the visiting spacecraft, and to achieve the forward, backward and radial rendezvous docking and separation with the space station, the Shenzhou team designed a new rendezvous path and orbiting mode, and added various functions of orbiting, rapid rendezvous and docking, and radial rendezvous and docking. Radial rendezvous and forward rendezvous are both normal rendezvous methods of Chinese space station manned spacecraft, which will be used alternately in future space station manned rendezvous and docking missions.