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Chang'e 5 was launched successfully, finishing the last chapter in China’s three-step moon exploration program
At 4:30 am on November 24, 2020, Chang’e 5 probe was launched successfully on a Long March 5 Launch Vehicle into the preset orbit at Wenchang Spacecraft Launch Site, achieving a complete success of the launch mission
As the last charpter in three-step (orbiting-landing-return) moon exploration program, Chang’e 5 will bring back samples to the Earth for the first unmanned sampling from the Moon. The Shanghai Academy of Spaceflight Technology undertook the R&D of Long March 5 booster and Chang’e 5 orbiter. The 4 boosters can provide 90% thrust for Long March 5 to take off, while as an active aircraft, the orbiter will undertake the missions of Earth-Moon transport, lunar orbit rendezvous and docking, sample container transfer, etc., and realize man’s first unmanned automatic rendezvous and docking, sample transfer in the lunar orbit, China’s first multiple separations, and first Moon-Earth transfer trajectory in the deep space environment, etc.
After being launched, Chang’e 5 orbiter will carry the lander, ascender and returner to complete Earth-Moon transfer, orbital modulation and braking at perilune. As it enters the lunar orbit, the orbiter will separate from the lander-ascender combination, and stay in the orbit with the returner. After that, the orbiter will actively rendezvous and dock with the ascender taking off from the Moon surface, complete man’s first automatic rendezvous and docking task in the lunar orbit, and transfer the sample container carried by the ascender to the returner. After being separated from the docking module, and the ascender combination, the orbiter will carry the returner to the Moon-Earth transfer trajectory, and the returner is separated at a distance of 5,000km away from the Earth, ensuring the initial conditions for re-entry.
Chang’e 5 orbiter, as a Earth-Moon conveyer, is operated throughout the entire exploration task, featuring “multiple roles in three aspects” as follows:
Firstly, multiple missions inflight phase.
It’s the first time for the orbiter to participate in 8 of the 11 flight phases of probe system, including carrier launching, Earth-Moon transfer, braking at perilune, orbiting the Moon, descending to the Moon’s surface, operation on Moon’s surface, ascending from Moon’s surface, rendezvous and docking, staying in the Moon’s orbit, Moon-Earth transfer and re-entry and recovery.
Secondly, multiple statusesbetween spacecraft.
There are 6 combinationstatuses in the flight of the orbiter, to undertake key tasks, including separation between spacecraft, rendezvous and docking as well as sample transfer. Besides, there are various combination flight statuses, and the interfaces between spacecraft are complicated. The orbiter should experience multiple orbital transfer and attitude adjustment, when executing the task, with huge difficulties in orbit flight, and attitude control, and high demand for the reliability of mechanical, electrical and thermal interfaces.
Thirdly, multiple separations.
The orbiter should succeed in completing Earth-Moon transfer, and carrying the returner with sample container back to Earth. The entire process involves 5 separations,including the separation with the rocket, the lander-ascender combination, the supporting module, the ascender combination of docking module, and the returner, involving several in-orbit separations, complicated separation environment and extremely difficult system design.
Therefore, Chang’e 5 R&D Team of Shanghai Academy of Spaceflight Technology has succeeded in making breakthroughs in highly reliable connection and separation technologies, lunar orbit docking and sample transfer technologies, general optimization and structural lightweight technologies, distributed and integrated electronic technologies, etc., solved difficulties in the R&D and ground test of claw-type docking mechanism, and ratchet-type transfer mechanism with connecting rod, laying a solid foundation for the follow-up exploration of the Moon and the deep space.