As the Long March 5 Yao-4 rocket rose from the ground, China's first independent Mars exploration mission, "Tianwen-1", started its journey to the fire. Since the 1960s, humans have carried out more than 40 Mars exploration missions, and Mars exploration in 2020 has once again become a global hot topic. Why do we choose Mars? Why is the fire detection so hot this year? What are the highlights of Mars exploration in various countries?
Choosing to pursue dreams Mars is related to the future of the earth
Since our ancestors slowly entered a civilized society from the wilderness era of eating raw meat and drinking blood, the sky above humans has become the most mysterious place. Currently, there are eight planets in the solar system. Mars is one of the planets closest to Earth that humans can explore. If humans want to break out of the Earth-Moon system to reach the next planet, they should theoretically start with the two neighbors of Mars and Venus. They are in the habitable zone in the solar system with the Earth, belong to rocky planets, and have the possibility of nurturing life.
However, through space exploration, humans discovered that Venus' environment was harsh: the air pressure was 92 times that of the earth, the air was almost full of carbon dioxide, and it was covered with dilute sulfuric acid clouds. The surface temperature remains at 460℃ all year round, and it is difficult for the detector to survive after landing, and humans cannot survive. In comparison, Mars has much "superior" conditions. The Martian environment is closest to the Earth, with an average surface temperature of minus 55℃; the atmospheric density is equivalent to 1% of the Earth, and the atmospheric conditions in the solar system are closest to the Earth; the light on the Martian surface is not too weak, solar energy is available, and due to the inclination angle of the rotation axis and the rotation period, The Earth is similar, and the length of day and night and changes of the four seasons of Mars are almost the same as those of the Earth.
Comparison of Earth and Mars volume. (NASA)
What is more important is that previous explorations have found evidence of water on Mars. Underground ice is widely present in areas above 40° of Mars; flowing ice was widely distributed in the mid-latitude areas of Mars. In September 2015, NASA officially announced the existence of liquid "brown" (ultra-high salt content liquid water) on the surface of Mars, which added hope for the existence of Martian life. Whether there are conditions for nurturing life on Mars and whether Mars is the past or future of the earth has become a major scientific issue in Mars' research.
Martian pebbles photographed by the Curiosity probe in March 2019.
At the same time, based on the existing space capabilities, the flight time can be reached for 8 to 10 months. Compared with farther planets and satellites, the mission cycle is more appropriate; Mars has the closest environment to the earth, allowing robots or humans to stay/resident on Mars. Become possible. Therefore, after manned landing on the moon, Mars became the first choice for humans to land on planets.
However, compared with lunar exploration, Mars exploration mission is more difficult. At present, there are only 24 of the 44 exploration missions carried out on Mars.
This is mainly because Mars is far away from the Earth, and it puts forward extremely high requirements for technologies such as launch, orbit, control, communication and power supply. Taking into account risks, costs and other factors, the best route from Earth's spacecraft to Mars is the "Horman Orbit" proposed in 1925. Since the orbit only appears once every 26 months, and the recent formation of the "Horman Orbit" is in the summer of 2020, the recent Mars exploration plans of various countries have been concentrated in this best false window. Especially since 1996, Mars rover has been launched in almost every launch window.
2020 Mars exploration in various countries has its own advantages
The United States, China, the UAE and other countries have previously stated that they will carry out Mars exploration missions this year. Among them, the UAE's first Mars rover, "Hope", has taken the lead and went from Kagoshima, Japan on July 20th The "Hope" is the first Mars rover in the UAE and even the Arab world, brought to the sky by the Japanese H2A launch vehicle. The US Perseverance will also be launched in the near future.
As the three major "fire exploration" projects are carried out in 2020, relevant countries will continue to increase their investment in deep space exploration projects represented by Mars, so as to occupy an unknown area involving "extraterrestrial resources". Advantage.
Although the United States, China and Arab countries all carried out Mars exploration missions in the summer of 2020, due to different technical level, project progress, scientific research priorities, etc., there are certain differences in the implementation of exploration missions in various countries.
United States: Preparing for "fire"
Perseverance rover. (NASA)
Public information shows that the "Perseverance" rover, which the United States plans to launch recently, is improved on the basis of the previously successful "Curiosity" rover. The Mars rover is equipped with the latest robotic arms, as well as scientific instruments such as Mars environmental dynamic analyzer, Mars subsurface radar imaging experimenter, etc. It can not only provide high-resolution 3D Mars pictures, but also preserve rock and soil samples and in the future belt Back to Earth. Other comments believe that as the country with the most advanced Mars exploration technology in the world, the United States' exploration mission is also laying the foundation for the next manned landing. For example, Perseverance carried an in-situ resource utilization experimenter for Mars oxygen element to convert carbon dioxide into oxygen; SpaceX, a private American sky exploration company, also plans to launch a "Red Dragon" Mars lander to Mars, for Moving to Mars in the future is a basic preparation.
China: Implement "surrounding"
days question number one at a time.
The probe of Tianwen-1, my country's first Mars exploration mission, consists of a landing cruiser (lander and rover) and an orbiter, and will achieve three steps of "orbiting patrol" at one time. The Mars Orbiter carries 7 scientific instruments, including high and medium resolution cameras, spectrometers, magnetometers, surface radars, ion and neutral particle detectors, etc.; the Mars rover carries 6 instruments, including ground penetrating radars, spectrometers, and small Weather stations, magnetic field detectors, etc. The scientific goal of this mission is to achieve scientific exploration of Mars' surface morphology, soil properties, material composition, water ice, atmosphere, ionosphere, magnetic field, etc., so as to establish a comprehensive and basic understanding of Mars.
UAE: Surround detection contains a "big plan"
Hope detector.
Compared with China and the United States, the UAE plans to launch the "Hope" Mars rover this time does not have a "fire plan". The rover uses orbiting Mars to study the Mars atmosphere and environment. With the loaded instruments, the probe will study the interaction between the lower and upper atmospheres of Mars and search for the connection between today's Martian weather and ancient Martian climate. However, the UAE is ambitious for the future of Mars. After the UAE successfully sent its first astronaut into space last year, the country also plans to invest $136 million to build a "Mars city" on Earth that replicates the Martian environment. "Mars City" is part of the UAE's "2117 Mars Strategy", which hopes to establish human settlements on Mars by 2117.
Attachment: Development History of World Mars Exploration
Phase 1: Overpass Exploration in the Early Research Period (1960-1970)
This stage of international space-sounding exploration is still in the early stage of research, and relevant countries mainly use Mars overpass exploration, transmit Mars pictures and exploration Atmospheric The parameters are mainly used, but the success rate of the detection task is not high, and only one case successfully completed the task. In 1962, the launch of the Mars 1A probe by the former Soviet Union was considered the starting point for international Mars exploration, but the probe lost contact with the ground while flying to Mars and eventually failed. Since then, the exploration missions of Mars 1 of the former Soviet Union and Mars rovers such as the United States "Sailor 3" also failed. It was not until 1965 that the United States "Sailor 4" completed its first Mars flight, becoming the first successful exploration Mars' artificial satellite. By the mid-to-late 1960s, the United States and the former Soviet Union's enthusiasm for Mars weakened, and they turned to concentrated on detecting Venus.
Stage 2: Preliminary understanding of the surface of Mars (1970-1990)
In the early 1970s, the United States and the Soviet Union re-launched Mars exploration activities, mainly focusing on orbital circumference and landing exploration. The main tasks include transmitting images, detecting the atmosphere, magnetic fields, Surface temperature, etc.
At this stage, the success rate of the detection mission has been significantly improved. Multiple probes including Mariner 6, Mars 2 and Pirate 1 have successfully completed the mission, especially the former Soviet Union "Mars" launched in 1971 The 2nd "probe successfully landed on Mars and became the first Mars lander. In 1972, the US "Sailor 9" arrived on Mars and became the first artificial satellite on Mars.Entering the late Cold War, the United States and the Soviet Union's investment in deep space exploration has decreased, and only the former Soviet Union launched two Mars satellite probes, and all failed. The main direction of Mars exploration has changed from launching a probe to studying data obtained from previous launches.
Phase 3: Exploring signs of life on Mars (1990-to-present)
After the end of the Cold War, Mars exploration has once again become a hot spot for deep space exploration. Many countries and regions led by the United States have carried out Mars exploration activities. The main method is landing exploration, and the main goal is to find evidence of the existence of Martian water and signs of life. During this period, a number of probes such as "Mars Express", "Courage", "Opportunity" and "Curiosity" were launched, and evidence of the existence of Martian water was successfully found.
column editor: Liu Kun Text editor: Liu Kun
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