The robot that only lived for 17 hours sent the photos to the earth 300 million kilometers away. What have you gained?

When it comes to space exploration, the first thing that most people think of is to go to Mars, the moon and other planets or satellites to collect resources, or to send humans to livable planets for interstellar migration.

But so far, we haven't enough ability to bring back the resources of alien celestial bodies, and the nearest livable planet is more than ten light years away. At the current speed of mankind, it will take at least 300,000 years to achieve it. Therefore, we can't do the two most important space exploration missions at this stage.

All we can do now is to explore the celestial bodies and cosmic environment near the earth. If we want to make a position for the current cosmic work, then it must belong to the preparatory work for exploring the universe.

At present, in the universe, we mainly focus on observation and detection, but with the development of science and technology, the methods and objects of detection have gradually changed.

At first, we could only observe the shining stars in the sky with telescopes on land. Later, we can gradually observe the unlit planets, satellites and asteroids. Later, we can send an aircraft into space to detect the difference between the vacuum environment in space and the earth's atmosphere.

Until now, we can send probes to Mars, Venus and even the boundary of the solar system. Even we can send humans to live in the space environment for a long time, and we can also collect samples of nearby celestial bodies.

The protagonist of today's article is a German probe, which helps spacecraft collect samples of asteroids. It sent back many photos and data to the earth at a distance of 300 million kilometers.

Hayabusa 2 was developed by Japan Aerospace Exploration Agency (JAXA) and set off from Earth in 20 14.

Hayabusa -2 is equipped with two propellers, one is chemical fuel propeller, which is mainly used when instantaneous acceleration is needed, and the other is ion propeller. The propulsive force of this propeller is generally only a few tens of millinewtons, and it can only propel an A4 paper on the earth, but it can continuously provide acceleration in space.

Hayabusa 2 is equipped with two detectors at the same time because its detection target is quite complex. It needs continuous power to support it to move freely in space, and it needs to land on an asteroid to collect data. It takes a lot of thrust to get rid of the asteroid's gravity after collection.

The main target of Hayabusa-2 is an asteroid named Dragon Palace, which runs in the orbit between the Earth and Mars. It belongs to an asteroid produced in the early days of the solar system. Because there is no material exchange with other stars, until now, the material of the Dragon Palace asteroid is almost the same as the material that just formed the solar system 4.6 billion years ago.

Because of the long distance, it took Hayabusa 2 three and a half years to reach the Dragon Palace on 20 18. Upon arrival, Hayabusa 2' s first task was to take a 360-degree full-body photo of the Dragon Palace asteroid and collect all its data while taking a selfie.

After taking the photos, Hayabusa II needs to land on the Dragon Palace asteroid to collect samples from the asteroid. There are two main targets, one is the soil and cosmic dust on the surface of asteroids, and the other is the underground rock samples collected. To achieve these two goals, Hayabusa II alone is not enough, but also needs help.

Our protagonist, German robot and asteroid surface detector (mascot) officially appeared.

The main task of German robots is to collect information on the asteroid surface and find a suitable landing site for Hayabusa II. However, the life of this robot is not long, and it is only 17 hours at most, so it is necessary to take time to investigate.

2018101October 3rd, the robot landed in the Dragon Palace. To be exact, it was thrown directly into the Dragon Palace. As a ground probe, it looks different from the well-known lunar rover and rover. It looks like a square box.

As a detector, it still needs to move around to collect more information. How to move the box? In fact, it is very simple, just install an ejection baffle on both sides of the robot. Just like a scallop, the robot can bounce up by the opening force of the baffle, turn over several times in the air and then fall down, and then the robot can move forward for a certain distance.

The diameter of the Dragon Palace asteroid is only about 1 km, and the asteroid's gravity is very small, only about 1% of the earth's gravity, so the escape speed of the Dragon Palace is centimeter-level, that is to say, as long as the robot's jumping power is too large and the speed exceeds several tens of centimeters per second, it can be ejected directly from space.

So it takes about fifteen minutes for the robot to bounce once, and every time it bounces, it needs a built-in kinetic energy roller to slow down. It is precisely because the gravity is too small that we can't use wheels to move, otherwise we will be hit by a pebble and the whole detector may be pulled off directly.

After solving the problem of movement, German robots can start collecting data information on the Dragon Palace. It mainly collects the material composition of the surface through photos, and also collects information such as surface temperature and surface firmness.

Under the camera of the robot, we observed the surface of the asteroid at close range for the first time. Unlike what we imagined, the surface of asteroids is not smooth and round, and the surface is mainly composed of gravel fragments, and dust and soil are very scarce.

Scientists infer that this may be because the asteroid's gravity is too low, and it is not bound by the atmosphere, so low-quality dust is easier to escape from the asteroid.

At this time, the problem came. The uneven surface covered with stones is very unsuitable for Hayabusa II to land. The only solution is to find a suitable landing site as soon as possible in the robot's 17-hour life.

Fortunately, before landing, Hayabusa II had made a long-distance comprehensive exploration of the topography of the Dragon Palace several months in advance, and combined with the detection results of the robot, it finally landed on the asteroid of the Dragon Palace from 2065438 to February 22, 2009.

After collecting samples of rocks and soil on the surface, Hayabusa 2 flew off the surface of the asteroid. But the landing collection can only collect samples of the asteroid surface.

However, the gravity on the asteroid surface is too small. Even if it landed on the surface, Hayato 2 was unable to drill holes in asteroids and collect samples from the interior of the earth's crust. Even with a drill bit, the whole machine of Hayato -2 will only be drilled overhead. At this time, Hayato 2 on the surface of the asteroid is as light as cotton.

So scientists chose another way to collect samples, let Hayabusa II leave the Dragon Palace asteroid, then launch a copper metal bomb over the asteroid, and accelerate the metal bomb with explosives. The accelerated copper bullet hit a crater on the surface of the Dragon Palace.

This is the first time that mankind has taken the initiative to use weapons to attack celestial bodies outside space. After the impact, a lot of asteroid dust was raised near the crater, and then Hayabusa 2 landed for the second time about 20 meters away from the artificial crater.

However, Hayabusa II could not move on the asteroid surface like a German robot, but when landing, the propeller blew up the dust near the crater, so Hayabusa II collected the raised dust and finally completed the second task.

After the two samples were successfully collected, Hayabusa 2 began its return journey and returned to orbit around the earth on June 5438+February 5, 2020. Then the sample recovery cabin was separated and placed on the earth, and Hayabusa 2' s mission was officially completed.

After the detection of Hayabusa 2, the distance between the Dragon Palace asteroid and the earth is only about 65.438+0.5 billion ~ 600 million kilometers. It is generally believed that only asteroids within 7.5 million kilometers from the earth will have a greater impact threat, so the threat of the Dragon Palace asteroid is not high. However, because the Dragon Palace is a kilometer in diameter, even if it is far away, it may still be captured by the gravity of the earth.

One of the important goals of Hayabusa 2 landing on an asteroid is to measure the gravity and mass of the Dragon Palace, so that scientists can calculate the probability of this asteroid hitting the earth.

In addition, two samples collected from asteroids gave scientists 5.7 grams of sand. Scientists have previously observed that the Dragon Palace asteroid may contain water and organic matter, but the detection of 5.7 grams of sand samples convinced scientists that there was water on the asteroid, but no organic matter was found.

Although no organic matter was found on the asteroid Dragon Palace, after years of research on celestial bodies, scientists found that there are many precursors in the universe-amino acids that make up protein.

Protein is the basic unit of life, composed of 20 different amino acids, and then protein formed the first prokaryotic life in the early days of the earth's formation, so life was born.

Through scientists' unremitting exploration of space, it is found that amino acids and water are ubiquitous substances in the universe, so it is inevitable that there is life in the universe. The detection results of asteroids such as Dragon Palace confirm this fact from the side.

Many people may not understand why they have to go to great lengths to send spacecraft to detect asteroids. In most people's minds, asteroids are just a huge stone, and there is nothing worth seeing.

But in fact, detecting asteroids is something that human beings must do. Because asteroids are mainly divided into two types, one is a small celestial body produced when the star system is formed, and the other is a celestial body outside the star system captured by the sun's gravity.

In the solar system, the vast majority of asteroids are the former, which means that most asteroids are homologous to the solar system. Studying the composition of asteroids can help scientists more accurately grasp the origin of the solar system and the distribution of matter in the universe.

It is by studying the composition of asteroids that scientists find that water is everywhere in the universe, mostly in the form of solid ice. Once these asteroids land on a planet with a temperature exceeding 0 degrees, they will be converted into liquid water or gaseous water vapor. This study proves that it is no accident that water appears on the earth, and the chances of life appearing in the universe will greatly increase.

In addition to studying the composition of matter, humans must also collect the parameters of asteroids, so that we can accurately predict the trajectory of asteroids. We know that 65 million years ago, the dinosaurs that dominated the earth for 200 million years were extinct due to the harsh global environment caused by the impact of asteroids on the earth.

Therefore, we must always be alert to the next impact of asteroids, so we need to obtain the accurate density and mass of asteroids, ensure that we can accurately calculate the trajectory of each discovered asteroid, and ensure that we have enough time to take corresponding defensive measures before it hits the earth.