Yesterday, tianwen-1 successfully completed the third orbital correction and continued to move toward Mars. Tianwen-1 is expected to land on Mars in May next year.

According to Liu Tongjie, spokesman for China’s first Mars exploration mission, tianwen-1 will fly for nearly four months in the future, and then it will face three difficulties. It is expected to land on the utopian plain of Mars’ northern hemisphere in May next year.

Tianwen-1 will have 1-2 midway corrections in the future

According to Liu Tongjie, when a rocket launches a detector, there will be orbit deviation, and there will also be deviation in flight control. If these two kinds of deviations accumulate over time, they will deviate from the intersection of Mars and Mars in space or time. In order to avoid “passing by” Mars, they need to be corrected in the middle of the orbit. So far, tianwen-1 has successfully completed three orbital midway corrections and one deep space maneuver. After that, there will be 1-2 midway corrections.

Liu Tongjie said that midway correction and deep space maneuver during the flight can not only ensure that tianwen-1 can accurately fly close to Mars, but also verify the engine performance in this process, so that it can ignite. It should not be in a silent state all the time in the long flight process, so it is necessary to order all kinds of engines in the midway. Deep space maneuver is to focus on a larger engine (main engine), and midcourse correction on a smaller engine, attitude control engine.

Tianwen-1 needs to break through at least three hurdles in order to successfully achieve the detection target

It will take nearly seven months for tianwen-1 to be launched and captured by Mars. It has been about three months since its launch on July 23, and it will be nearly four months later. According to Liu Tongjie, tianwen-1 is still facing three difficulties.

The first difficulty is to capture near fire within the gravity of Mars. After the probe reaches the gravitational range of Mars, it needs to “step on the brake” to slow down the probe to avoid flying out or hitting Mars. The Mars “captured” probe will orbit Mars for 2-3 months.

The second difficulty is that after the spacecraft completes its orbit mission, it needs to find a very good small window to let it enter the Martian atmosphere. Mars has an atmosphere, the density of which is about 1% of the earth’s atmosphere. After atmospheric deceleration (aerodynamic deceleration, parachute deceleration) and thrust reverser engine deceleration, the landing leg lands on the surface of Mars to absorb impact energy. This process is very difficult. Just like the space (re-entry) module entering the earth, there will be a blackout (communication interruption) for about 8 minutes in the process of atmospheric deceleration, and the communication can not get the signal. Due to the long distance, there is a long time delay from Mars to earth, so it is impossible to realize real-time control. Therefore, the EDL process of entry / deceleration / soft landing is controlled by tianwen-1 independently, not by the ground.

The third difficulty is that the soft landing on the surface of Mars is not finished yet. We need to release the rover to the surface of Mars, let it walk and carry out exploration. There are six scientific instruments on the rover to play a role. We know very little about the environment on the surface of Mars. If the soft landing is on the surface of Mars and the landing point is not flat or the attitude is not correct enough, how can the rover drive down? You can get down from the front of the track or from the back. You can see the attitude and terrain of the landing at that time.

If you want to successfully complete the Mars exploration mission, these three difficulties must be overcome.

Tianwen-1 is expected to land on Mars in May next year

According to Liu Tongjie, after a long flight, tianwen-1 is expected to land on the utopian plain in the northern hemisphere of Mars in May next year. Most of the international Mars exploration missions with landing plans choose to land in the northern hemisphere of Mars. Because the southern hemisphere is mostly mountainous and uneven, and the northern hemisphere has plains. Tianwen-1 will land in the south of Utopian plain. Geologists think it’s probably the site of an ancient ocean.

Liu Tongjie said that this landing site is at the junction of ancient ocean and ancient land. Scientists believe that this place has high scientific value and is likely to achieve unexpected scientific results. This is also the reason why we chose this place for soft landing and patrol exploration.

Tianwen-1 has taken the first step in China’s planetary exploration, and there are many subsequent mission plans

According to Liu Tongjie, China’s planetary exploration program has planned four missions. The first Mars exploration tianwen-1 mission is the first and has been launched. At present, other missions are under demonstration. The second planned asteroid exploration mission is expected to be implemented around 2024. The third is a Mars sampling return mission around 2030. In addition, there will be another exploration of the Jupiter system and interplanetary space around 2030, that is, after the exploration of Jupiter and Ganymede, we will fly further into deep space.

The stars of the universe are vast and bright, and China’s aerospace wind is flying. Under the background of the new era, Chinese people are more and more confident and firm in marching further into the deep space. As China’s first interplanetary exploration mission, let’s look forward to tianwen-1’s successful arrival on Mars, leaving a “Chinese mark” on this mysterious planet and achieving the expected scientific goals.

(source: wechat account of China Lunar Exploration Project)

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