The ancients called Mars "twinkle", indicating war and disaster. There is an idiom called "Mars stays in Antares", which is often recorded in ancient books. It refers to a rare astronomical phenomenon. Mars and the earth have different angular velocities around the sun, and sometimes overtaking occurs. From the earth's point of view, when Mars turns near Scorpio, it will go retrograde for a while and go forward for a while. The ancients thought this was an ominous sign, indicating that the emperor died and the prime minister stepped down. Historical records? There is a saying in the Biography of Qin Shihuang: "In thirty-six years, Mars stayed in Antares". Before the death of the first emperor, there was an astronomical scene of "Mars stays in Antares".
Why does Mars arouse the curiosity of human exploration? Giovanni? Italian astronomer Schiaparelli spent his whole life observing various celestial bodies in the solar system. 1877, he found in the telescope that there were many "linear grooves" on the surface of Mars, which were probably canals built by Martians to irrigate farmland. How to verify the guess, it is not enough to rely on the telescope alone. The close observation of the launch detector is the most credible.
The way to detect Mars is similar to that of the moon, and it is divided into five links. The first step is orbiting. The probe orbits Mars and takes photos. The second step, landing, the probe landed on Mars. The third step, patrol, the rover landed and looked around. The fourth and fifth are more difficult. First, we got some rocks and soil from Mars to study. Finally, we let people land. In the process of lunar exploration, all five methods have been used, and they have all succeeded. But Mars is too far away from us. If a probe is launched on earth, it will take six months to reach Mars. If you want to fly back, there is not enough fuel, which is too difficult. At present, no country can do it.
"Tianwen-1" will complete the circumnavigation, landing and patrol in one breath, which is the first time in the history of space flight. This is a pioneering work of China people, and there are many challenges to overcome. First of all, the fuel carried by the detector is limited, so it is necessary to design the flight path accurately. Secondly, after approaching Mars, it is difficult to be captured by Mars and enter the predetermined orbit. If it is not good, it will pass. The biggest challenge of the exploration mission is landing. It takes seven minutes for the speed of the detector to drop from 4.8 kilometers per second to zero, during which the transmission of radio instructions is delayed and cannot be accurately controlled. In addition, the weather will also affect the landing, and if it encounters a Martian storm, it may lead to the failure of the mission. After overcoming these difficulties, Tian Wen-1 embarked on a trip to Mars. The scientific instruments it carries will detect the topography and soil composition of Mars.
1960, the Soviet Union was the first to launch a Mars probe. By the end of June this year, exploration activities in various countries had been carried out 44 times, with few successes and the most failures. During the Cold War between the United States and the Soviet Union, a fierce "Mars race" took place. In May, 197 1, just 30 days, the two sides launched five times in a row. Mariner 9 of NASA, a latecomer, became the first Mars orbiter. Note that it was the first "orbiter", 1964. The American "Mariner 4" also reached Mars and passed by, but it didn't orbit Mars, so it wasn't an orbit. As mentioned earlier, the Soviet Union launched the probe first. How did America become the first? Launching does not mean success. Throughout the 1960s, the Soviet Mars program failed.
But this does not mean that Soviet technology is not good. Venus is a close neighbor of the earth, its surface temperature is as high as 500℃, its atmospheric pressure is 90 times that of the earth, and it often rains with sulfuric acid in the sky. It is a real purgatory on the earth. The United States, Europe and Japan only dare to explore around. Once they land, the high-pressure environment will crush the detector instantly. One exception is the Soviet Union. 1970, "Venus 7" landed successfully and worked continuously at high temperature and pressure for 23 minutes. Venus 8, which landed later, not only tested the soil, but also televised the sunshine and clouds on the surface of Venus.
At present, there are eight probes that have successfully landed on Mars: Pirate 1, Pirate 2, Pathfinder, Opportunity, Spirit, Phoenix, Curiosity and Insight, all made in the United States. Both Russia and the European Union tried to land, but both failed. The round-trip signal transmission between Mars and Earth takes at least 6 minutes, and the delay is too long for the instruction to be issued in time. Someone pushed your crystal, and you are still playing wild. In addition, the probe landed in free fall. What can I do to land safely? Three magic weapons, recoil rocket, airbag and aerial crane.
The first way is the simplest. In 1976, the Viking 1 and Viking 2 launched by NASA used recoil rockets. After flying in the orbit of Mars for a period of time, the probe entered the atmosphere of Mars, opened the parachute, and started the recoil rocket when it was about to land, and landed smoothly. How does the airbag land? It wraps the rover, inflates tens of meters above the ground, and bounces repeatedly when landing to achieve buffering. The blackest technology is the "aerial crane". The rocket aircraft hangs the detector, lands safely, and then cuts the lanyard and flies away. In 20 12, NASA used this method for the first time and sent more than 900 kilograms of Curiosity to the surface of Mars.
What is the key to launching a Mars probe? High thrust rocket engine. German V-2 rocket engine is the originator of American and Soviet space technology. Without it, Gagarin could not go to space, and Armstrong could not land on the moon. Before the end of World War II, the United States and the Soviet Union began to make plans for how to seize German rocket technology and experts at the first time. Smart Americans, as soon as they entered Germany, immediately collected technical drawings and scientists, leaving only rocket parts for the Soviets.
In order to repair the V-2 rocket as soon as possible, the Soviets came up with an ingenious idea-"bread for technology". Although the United States has taken away important rocket designers, the workers in the rocket factory are still there, and they have rich manufacturing experience. Just after the war, there was a shortage of food. We distributed food to these people and recruited them back to the factory to help repair the V-2 rocket engine. Later, the F- 1 engine of Saturn V in the United States and the RD- 170 engine of Soviet Energy were all disciples of V-2.
During the Cold War, the United States and the Soviet Union competed for scientific and technological hegemony, and space technology advanced by leaps and bounds. Stimulated by ideology, the people of the two countries, like chicken blood, supported the government to invest heavily in rockets and develop spacecraft. From 65438 to 0966, the budget of NASA even accounted for 5% of the total budget of the federal government, which is very high. At that time, Apollo spacecraft and Saturn V rocket were very mature. If the United States has been investing regardless of the cost, it is really possible to complete the manned landing on Mars in the 1970s. Unfortunately, after Nixon took office, he faced a huge government deficit and could only cut the space budget. In order to show the Soviet Union the superiority of the American system, we must tighten our belts and engage in space flight. Now that the goal of landing on the moon has been achieved, there is no need to get fat again.
The budget of NASA has been cut, and its expenditure still ranks first in the world. In 2020, Trump allocated $2 1 billion, exceeding the combined space budgets of other countries. China's budget is only one-tenth that of the United States, and some people think that landing on the moon is useless. Space technology has penetrated into every aspect of life, and global positioning system, jet airliner and remote sensing prospecting technology have been widely used. In 1950s, China began space exploration. At that time, the domestic raw materials, semiconductors, instruments and other industries were almost blank, and aerospace projects promoted the development of these industries. According to the statistics of China Aerospace Science and Technology Corporation, 80% of more than 1000 new materials developed in China were developed in space exploration projects, and nearly 2,000 space technology achievements have been applied to various industries of the national economy. How did American technological hegemony come from? A simple example, commercial GPS, provides global positioning services, gains profits, and then supports technology research and development. This is a perfect cycle. It is necessary for China to vigorously develop space exploration.
From the Soviet Union, to the United States, to Europe, it was China's turn to get on the bus. After more than 50 years of exploration, Mars has only heard English greetings, and they are all American. But on 202 1, it will welcome a new partner who can speak Chinese, Tian Wen No.1. Although the experience of predecessors tells us that this road is not easy, the goal of the Chinese people is the sea of stars.