Key 7 minutes of Mars landing simulation test in China is the most challenging

 Key 7 minutes of Mars landing simulation test in China is the most challenging

Hello, Mars, China is coming! said Ma Jun, a special reporter from global times in Hebei On November 14, with the first public appearance of Chinas Mars exploration mission, many netizens gave out such cheers. On the same day, Chinas National Space Administration invited about 70 foreign embassies, international organizations and journalists from Chinese and foreign media to Huailai, Hebei Province, to observe the hovering obstacle avoidance test of Chinas first Mars exploration mission lander and visit relevant test facilities. The reporter of Global Times learned on the spot that Chinas first Mars exploration plan will be held in 2020. After seven months flight, Chinas Mars probe will undergo the most critical 7-minute landing test. This hovering obstacle avoidance test is based on this.

Status of Mars exploration mission lander after hovering obstacle avoidance test Ma Jun / photo

According to the position relationship between the earth and Mars, every 26 months, there will be the best time window for launching the probe from the earth to Mars. Launching the Mars probe at this time point will save a lot of fuel and shorten the arrival time. 2020 will usher in a window period, so next year is called the international year of Mars exploration, including China, the United States, ESA, India, the United Arab Emirates and other countries and international organizations have announced their own Mars exploration plans.

Before arriving at the scene, the reporter of the global times had been curious about the question: the gravity of Mars is far smaller than that of the earth. How can we simulate the gravity environment of Mars on the earth? Do you have to use buoyancy to counteract part of the gravity in a large pool, as astronauts do in weightlessness training? After the reporters bus drove into the so-called Asias largest Chinas comprehensive test ground for the landing of extraterrestrial objects, a group of tall steel frame structures opened up the answer.

Zhang Rongqiao, chief designer of Chinas first Mars exploration mission, said that the natural environment of Mars is quite different from that of the earth, of which gravity is only one third of that of the earth. In order to simulate landing on Mars, Chinese aerospace researchers have built a set of facilities. It consists of three parts: the tower system, the servo system and the surface simulation area of Mars on the ground. The most prominent is the six steel tower columns, which are connected into a rigid column structure through the ring truss above. The height of the tower is 140 meters, and the diameter of the inner ring is 120 meters, which is enough to meet the space of simulated Mars landing.

The follow-up system is the red platform in the middle. It is fixed by 36 steel cables, and the Mars probe with four legs is suspended below. By precisely controlling the velocity of the platform, it can bear part of the weight of the probe, and then simulate the gravity environment of Mars for the probe.

In addition, special materials are laid on the ground under the tower to form various pit and slope shapes, so as to simulate the surface characteristics of Mars and test whether the relevant optical and electronic equipment carried by the probe can play a role in the descent process.

The experiment on the 14th was to simulate the whole process of the Mars probe hovering at a height of 67 meters from the surface of Mars, and independently searching for the ground safe landing area full of pits and gravels, and then avoiding obstacles and falling to 20 meters.

5u30014u30013u30012u30011u2026u2026 The test is on! The reporter of global times saw that with the roar of the ear, the Mars probe, which was suspended in the sky, began to shoot down the flame, and then began to slowly descend. However, the descent did not last long. The detector suspended in the air and adjusted its position to the left, avoiding various obstacles on the ground to find a suitable landing place. After the position is found, it slowly descends again, and finally stops at the height of 20 meters.

Why do we have to make great efforts to build such simulation test facilities and carry out repeated tests? Zhang Rongqiao said that Chinas first Mars exploration mission is planned to be carried out in 2020. The goal is to realize Mars encircling and landing inspection through a launch mission, carry out global and comprehensive Mars exploration, and conduct fine inspection and exploration of key areas on the surface of Mars. At that time, the final landing process of the probe is only 7 minutes after it reaches Mars after 7 months flight. But this is the most difficult and challenging part of the plan.

An aerospace expert told the global times that there is a great risk in the process of autonomous obstacle avoidance and landing of spacecraft. The lunar probes launched by Israel and India this year all crashed out of control at this stage. Compared with the moon, which is about 380000 kilometers away from the earth, the distance between Mars and the earth is more distant, and the nearest distance is 55 million kilometers. Even the one-way transmission of radio signals takes 4 minutes, which means that in the critical landing process, the detector can only deal with all the problems encountered by itself, and the requirements for the detector to deal with emergencies are very high, which is more difficult than the lunar exploration The tester is larger. However, the Mars environment is extremely complex. In the history of Mars exploration, more than half of the worlds probes have failed.

According to the introduction, at present, the landing methods of Mars probe are mainly divided into three categories: air bag bounce type is mainly suitable for relatively small probes, such as the Mars Pathfinder, courage and opportunity Rovers in the United States. The safe landing can be realized by inflating the air bag before landing and buffering with the air bag; reverse landing leg type is mainly to use the reverse rocket To provide the final landing buffer force, which is suitable for the larger Mars probe; air Crane type is the landing mode adopted by the U.S. curiosity Mars rover and other super large probes, which provides the buffer by the anti thrust rocket hanging from the top of the probe, puts the probe on the surface of the fire star and then disengages. The reporter of the Global Times noted that the test of Chinas Mars probe adopted the push back landing leg type, in which the key hovering obstacle avoidance technology has been mature application in the process of surface landing of change-3 and change-4.

China Aerospace continues international cooperation

Although the Chinese delegation was absent from the 2019 IAF general assembly, which opened on October 21, due to the intentional obstruction of the US and the failure to issue visas in time, China Aerospace did not change the purpose of international cooperation. Zhang Kejian, director of the National Space Administration, said Thursday that China stands for strengthening international exchange and cooperation in space and sharing the achievements of space development on the basis of equality, mutual benefit, peaceful utilization and inclusive development. It is understood that in the future, China will also carry out deep space exploration projects such as Mars sampling return, asteroid exploration and Jupiter exploration. Zhang Kejian said that Chinas National Space Administration is willing to work with space agencies, space science research entities and foreign space science enthusiasts to strengthen cooperation in the follow-up major space engineering tasks and jointly promote the development of space industry.

Zhang Kejian revealed that NASA sent invitations to representatives of the United States, Russia, Europe and other countries and international organizations in China to observe the hovering obstacle avoidance test of the Mars Lander on site. According to the global times, there were 19 envoys from France, Italy, Brazil and other embassies in China on the same day, and representatives of the European Union, the African Union mission in China and the Asia Pacific space cooperation organization attended the event.

According to reports, in the past 60 years, China has actively promoted international cooperation. It has signed more than 140 space cooperation agreements with 45 countries and international organizations, jointly developed China France maritime satellite and astronomical satellite with France, jointly developed China Italy electromagnetic satellite with Italy, and jointly developed China Brazil Earth Resources Series satellite with Brazil, which is known as the code of south south high tech cooperation Fan; in the change-4 mission, he has carried out active international cooperation with Germany, the Netherlands, Sweden, Saudi Arabia, Russia, Argentina and other countries. In April this year, he released the announcement of cooperation opportunities on change-6 and asteroid exploration. Recently, at the general meeting of the organization for earth observation, he announced that the 16 meter resolution optical data of gaofen-1 and gaofen-6 satellites will be open for sharing globally. These initiatives have brought benefits for expanding the sharing of space technology achievements and promoting social and economic development among more countries, especially developing countries.

Source: Global Times - global network editor in charge: Wang Xuyu b12062