2020-07-15

ready to go! Towards the mysterious and dangerous Mars

By yqqlm yqqlm

On the 14th, according to the information published by the China Academy of Space Technology, recently, the Mars probe “Tianwen 1” developed by the Institute has been delivered to the Wenchang Space Launch Site. China’s first Mars exploration mission is about to start.

The National Aeronautics and Space Administration of China announced the name and logo of China’s first Mars exploration mission at the launching ceremony of “China Aerospace Day” on April 24. The Chinese planetary exploration mission was named “Tianwen (Tianwen) series”, the first Mars exploration mission was named”Tianwen 1″, and subsequent planetary missions were numbered sequentially.

2020 is the window period for Mars exploration activities. According to the plan, this year China will use the Long March V launch vehicle to launch the Mars rover, realize the”three steps” of Mars orbiting, landing and patrol detection at one time, carry out global and comprehensive exploration of Mars, and conduct detailed patrols on key areas on the surface of Mars. Survey.

It is understood that the Chinese Mars rover is divided into two parts, the surround and the landing patrol, which were developed by China Aerospace Science and Technology Corporation. The rocket launches the detector to the ground fire transfer orbit, then with the support of the ground measurement and control system, through multiple orbit maneuvers and midway corrections, the brake is applied at the near fire point, enters the ring fire elliptical orbit, and runs to the selected entry window , The detector will perform derailment control and release the landing patrol.

After the landing patrol enters the Martian atmosphere, it adopts aerodynamic shape, parachute, reverse thrust engine and other multi-stage deceleration and landing leg cushioning. After the separation of the Mars Rover (namely the patrol device) and the landing platform, regional patrol detection will be carried out. The surround will provide relay communication links for the rover and carry out scientific exploration around.

In 2020, in addition to China’s Tianwen-1, there will be the US’s “Fortitude” rover and the UAE’s “Hope” Mars rover. The ExoMars rover rover, which was originally scheduled for”fire detection” this year, has cooperated with Russia and has announced that it will be delayed until 2022.

As the neighbor of the earth, beautiful Mars has always been a mysterious and dangerous place in human imagination. There are no shortage of”Martian” correctional images in science fiction works from ancient times to the present, they can be insect-shaped, jellyfish-shaped, star-shaped, Hiding in dark corners, plotting one after another aggression against the earth.

The Martians in the movie”Martians Turn Around the Earth”

In real life, humans have never given up on the journey of exploring Mars. As of the end of 2014, the United States, Russia, Europe, Japan, and India launched 42 Mars probes to Mars, with a successful or partially successful mission 22 times. With such a high failure rate, Mars has been called the”detector’s cemetery” or”death planet”. So, what is the reason for these detectors to”go nowhere”?

Explore the first level of Mars-leave the earth

The mission of the launch phase is to send the Mars probe from the ground into the ground-fire transfer orbit, it It is the first step of the entire Mars detection. About 30%of the fire detection faults occurred during the launch phase. In more than 50 years of Mars exploration activities, many failures have been caused by the failure of launch vehicles.

Most of these launch vehicle failures occurred in the early stages of human fire detection. One of the important reasons was that the capability, accuracy and reliability of the launch vehicle at that time could not fully meet the demand.

In the space competition between the two superpowers of the United States and the Soviet Union during the Cold War, the fire detection plan was launched quickly, especially the Soviet Union’s first 10 fire detection missions from October 10, 1960 to May 1971. Failed, 7 of them appeared in the launch phase.

After entering the 1970s, the launch vehicle technology has made rapid progress and has become increasingly mature. But even so, there were still major accidents that caused launch failures due to the failure of the upper stage of the launch vehicle. In November 1996, Russia chose the Proton rocket to launch the Mars-8 probe, but after it entered orbit around the earth, it crashed into the South Pacific due to the failure of the second ignition of its fourth-stage engine.

The success rate of the Proton series launch vehicle is 87%

Explore the lost orbit of the second pass of Mars

To board Mars, The probe must first cut into Mars orbit. The difficulty of getting into Mars orbit is equivalent to playing a golf ball from Paris, which just fell into a hole in Tokyo.

In December 2003, Japan’s Hope Mars probe flew in space for 5 years due to technical failure. At the last moment, it failed again. It was a pity that it passed by Mars and became a circle around the sun. Artificial planet.

Hope:Originally I just wanted to go to Mars and accidentally become a visit to the solar system

So, how to enter Mars orbit? First, we must choose the appropriate cutting height. If the probe is too far away from Mars to be captured by Mars, it will pass through Mars; if the entry point is too close to Mars, it may crash on Mars Atmosphere. Then there is the size and length of the braking speed, too large or too small, too long or too short will affect the probe to accurately enter the predetermined Martian orbit.

Explore the third level of Mars-the number of landings

The most dangerous landing on Mars, this process is only six minutes, but is called” Six terrifying minutes.”

The atmosphere of Mars is thin and cold compared to Earth. The atmospheric density of Mars is about two orders of magnitude smaller than that of Earth, which is only equivalent to the atmospheric density of the Earth at a height of 30km.

Mars captured by the Viking probe

After entering the Martian atmosphere, what the probe’s heat protection measures are, and whether parachutes, airbags, and buffer rockets can work in accordance with the procedure is crucial. It must be very precise. In addition, a stone on Mars or a gust of wind may destroy the original plan.

Therefore, this stage is also a very critical stage. Because there are many factors that can cause failure or failure, the failure rate is similar to the launch stage, reaching 26.8%.

Curious Mars Rover landing on the surface of Mars through the”air crane”

< strong>Explore the fourth hurdle of Mars-Death Planet

Don’t think that after spending “six minutes of terror” everything will be fine. The surface environment on Mars is very complicated and the climatic conditions are bad. Will give up before.

The surface temperature of Mars is extremely low, which has high requirements for the temperature regulating device of the probe; the atmospheric density of Mars is only about 1%of the earth, and the radiation is quite serious; the surface of Mars is very uneven, filled with pits and rocks , The probe is likely to fall into a trap covered by soft volcanic ash; the dust storm on Mars is also terrible, sometimes reaching 6 times the intensity of the 12th typhoon on Earth, lasting up to one year… only to overcome this one difficult problem In order to survive on this planet.

The surface of Mars is covered with stones and pits

In 1971, the Mars-3 landing launched by the Soviet Union was successful. This was the first Mars soft landing in the world, but only on Mars. After 20 seconds of data on the surface, the lander was destroyed in a Martian dust storm.

Mars-3 probe

Although only a part of the probes can explore Mars after years of hardship, humans have made important progress through unremitting efforts for decades.

In fact, every exploration mission, regardless of success or failure, has brought about technological innovation:the airbag landing shock absorption technology adopted by Mars Pathfinder, Courage and Opportunity; Phoenix is ​​based on Bracket-buffered landing system; aerial crane landing technology used by the Curiosity rover, etc.

Phoenix’s landing system with support cushioning

Each innovation not only plays a vital role in the success of its mission, but also promotes the progress of deep space exploration technology, It has laid a solid foundation for future manned Mars exploration and other interstellar exploration missions.

Since the beginning of the 21st century, the success of six major Mars exploration missions in the United States and the success of the ESA Mars Express orbiter indicate that Mars exploration technology has become increasingly mature. Humans have initially mastered the orbital detection of Mars and the fixed-point detection and patrol detection on the surface of the robot, and obtained fruitful scientific achievements. It may not take long for humans to grow potatoes on Mars just like Matt Damon in the movie”Mars Rescue”.

The Mars Potato Base in the movie”Mars Rescue” (the”horror story” of Mars in distress)

Article source/China News Network, CCTV News, Science Popularization China, etc.

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