(Interview between the two sessions) Three questions about "Tianwen No.1": Where did it fall? How to fall? How to detect?
China News Service, Beijing, March 9th, title: Three questions about "Tianwen No.1": Where did it fall?
How to fall?
How to detect?
Author Guo Chaokai Xu Pengpeng Wang Chao
After 7 months of full-speed advancement, the Tianwen-1 probe arrived in Mars orbit in February this year and returned high-definition images of Mars in the near future.
Next, when will Tianwen-1 land on Mars?
Where did it fall?
How to fall?
What scientific research exploration will be carried out in the future?
The reporter recently interviewed Zhao Xiaojin, a member of the National Committee of the Chinese People's Political Consultative Conference and Secretary of the Party Committee of the Fifth Academy of China Aerospace Science and Technology Corporation, to find out.
Data map: The Long March 5 Yaosi rocket ignited and lifted off at the Wenchang Space Launch Site in China.
Photo by Luo Yunfei
Where did it fall?
In the history of human exploration of the solar system, Mars has always given people unlimited expectations and reveries.
Up to now, more than 40 Mars explorations have been carried out globally.
Compared with previous detections, the Tianwen-1 mission is expected to set a precedent.
Zhao Xiaojin pointed out: "Tianwen 1 is China's first Mars exploration mission. We will achieve a'circumnavigation' of Mars through a mission, three steps and one step, which is unprecedented in the world's history."
Mars is so big, and the climatic conditions, topography, and atmospheric conditions are extremely complicated. Where is the ideal landing zone for Tianwen-1?
Zhao Xiaojin said that the aerospace experts selected the Utopia Plain, the largest plain on Mars, for the landing area based on the principles of low project realization risk and high scientific exploration value based on the full demonstration of science and engineering.
According to reports, the preferred landing site for the Tianwen-1 probe is located at the southern end of the Utopia Plain, and the alternative site is located in the magma flow zone of the Elsion Volcano in the southeast of the Utopia Plain.
Why did the landing zone choose the Utopia Plain?
Experts explained that the Utopia Plain is located in the northern hemisphere of Mars.
The topography, geological structure, surface and subsurface rocks and minerals of the southern and northern hemispheres of Mars are very different.
The southern part of Mars is highlands, and 60% of these highlands are covered with "scarred" craters.
The northern part of Mars is a low plain filled with volcanic lava. The terrain is flat, with fewer craters, a younger geological age, and a thinner crust. Therefore, the Utopia Plain in the Northern Hemisphere is of course chosen as the landing zone.
Data map: The Long March 5 Yaosi rocket ignited and lifted off at the Wenchang Space Launch Site in China.
Photo by Luo Yunfei
How did it fall?
According to the plan, the Tianwen-1 probe will choose an opportunity to land on Mars from May to June this year to carry out follow-up inspections.
Zhao Xiaojin said that at this stage, Tianwen-1 will orbit Mars for nearly three months to observe and collect relevant data on Mars to determine the exact location of the final landing, "in case it encounters a place with a steep slope during landing. , Will affect mission safety, so data collection at this stage is very important."
After selecting the landing site, how to successfully land on Mars is a big problem.
Experts say that the Tianwen-1 probe must cut into the Martian atmosphere at a perfect angle. If the angle is too small, it will not be able to enter the atmosphere. If the angle is too large, it will be burned by the atmosphere overheating.
During the reentry, descent, and landing process, the probe needs to reduce its speed from about 20,000 kilometers per hour to zero in less than 10 minutes to achieve a soft landing.
Liu Tongjie, deputy director of the China National Space Administration's Lunar Exploration and Space Engineering Center, once revealed that the deceleration process of Tianwen-1’s landing on Mars includes atmospheric deceleration, aerodynamic deceleration, parachute deceleration, and reverse engine deceleration. Landed on the surface of Mars.
Due to the considerable distance, there is also a long time delay from Mars back to the earth control ground station, and it is impossible to achieve real-time control.
Therefore, the Tianwen-1 landing on Mars must be done autonomously by the probe.
What to explore?
After successfully landing on Mars, what scientific research will Tianwen-1 carry out on Mars?
In this regard, Zhao Xiaojin said that Tianwen-1 will realize scientific exploration of Mars' surface morphology, soil properties, material composition, water ice, atmosphere, ionosphere, magnetic field, etc., thereby establishing a more comprehensive understanding of Mars by mankind. know.
For a long time, people are most concerned about whether there is life on Mars, which has become a hot issue in current Mars exploration.
According to expert analysis, the Utopia Plain is likely to be the location of the ancient oceans of Mars, and the place where Tianwen-1 is about to land is at the junction of ancient oceans and ancient land.
In September 1976, the US "Pirate II" Mars rover also landed here and sent back photos of frost.
The latest scientific exploration found that there is a large amount of groundwater ice under the shallow bottom of the Martian Utopia Plain 1 to 10 meters above the ground, and the water storage is equivalent to the largest freshwater lake on the earth-Lake Superior.
There is water on Mars. Does it mean that Mars has existed or that life has existed? Does it mean that Mars is the future of the people on Earth?
These questions have to be further answered by Tianwen No.1 in this magical place of Utopia Plain.
"Previously, foreign probes discovered the existence of water ice on Mars, but there is no definite sign of life. Mars is a hot spot for human deep space exploration. Foreign countries are also training Martian astronauts. It will not be a dream for humans to land on Mars in the future. "Looking forward to the future, Zhao Xiaojin looked forward to saying, "In the vast universe, mankind will eventually go to more distant deep space." (End)