China News Service, Xi’an, May 15th (Reporter Zhang Yichen) "For 10 months, our hearts have been flying in deep space with'Tianwen-1'. Now the soft landing on Mars has been successfully achieved, which fully verified the development of our institute. The performance of the 78 engines in the world has added confidence to us in completing the follow-up mission." said Wang Wanjun, the director of the Sixth Academy of China Aerospace Science and Technology Corporation (hereinafter referred to as the Sixth Academy of Aerospace).
On May 15, Beijing time, the Tianwen-1 Landing Patrol steadily landed on the pre-selected landing zone-the Utopia Plain in the northern hemisphere of Mars. China's first Mars exploration mission to Mars was successfully landed.
It is understood that the successful landing of the Tianwen-1 probe on Mars needs to reduce the speed of more than 20,000 kilometers per hour to zero in just 9 minutes, during which it needs to go through multiple links such as aerodynamic deceleration, parachute deceleration, dynamic deceleration, and landing buffer. Nothing can be missed.
After a series of deceleration measures, "Tianwen-1" came to a distance of about 2 kilometers from the surface of Mars and continuously approached the surface of Mars at a speed of about 100m/s.
This speed is equivalent to the current maximum operating speed of China's high-speed rail.
The 7500N variable thrust engine developed by the Sixth Aerospace Research Institute is the main tool for the final power deceleration link.
Effect picture.
Photo courtesy of the Sixth Academy of China Aerospace Science and Technology Corporation
In the daily driving process, whether the brakes are frequently slammed is one of the important indicators to measure the level of a driver.
Similarly, in order to reduce the impact on the landing patrol during the landing process and deliver the "passengers" smoothly, the engine adopts the technique of "long-distance light braking", which will complete variable thrust adjustment according to preset timing and real-time instructions. The landing patrol was slowed down, and finally landed smoothly on the surface of Mars at a very low speed.
China's first Mars exploration mission, Tianwen-1, successfully embarked on a journey to fire on July 23, 2020.
On February 10, 2021, the Tianwen-1 probe entered the orbit of the ring fire, carried out scientific exploration work, and obtained a large amount of scientific data.
Since then, the probe has been in orbit on Mars for about three months to conduct detailed investigations of the topography, landforms, sand and dust weather of the Utopia Plain in the pre-selected landing area, and prepare for landing on Mars.
Another difficulty in soft landing on the surface of Mars is that the surface of the moon is approximately vacuum, while the surface of Mars has a thin atmosphere.
During the landing process, the lander and the atmosphere on the surface of Mars will violently rub against. In order to prevent it from being "burnt", a heat-resistant outsole was added to the lander, and the engine that could have been "stretched out" was "pocketed up".
Limited cabin space limits the size of the engine. The height of the variable thrust engine of the Tianwen-1 probe is more than 60% smaller than the variable thrust engine of the Chang'e-3 probe, but the main performance indicators such as thrust remain unchanged. "To burst out "big energy", this means that the engine must be stronger.
The total weight of "passengers" that can be carried on the "Tianwen No. 1" fire trip is limited.
Starting from the principle of the engine, the scientific researchers optimized the system parameters and the final assembly layout according to the requirements and characteristics of the task, which not only ensured the function, but also added some new technologies, applied some new materials, and the engine has no "long flesh". Muscle gain", weight has also been reduced by 2/3, giving way to other "passengers", further promoting the variable thrust engine's high-performance, long-life, and high-reliability characteristics, solving the above problems in one fell swoop.
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