US scientists plan to use ground laser to shoot down space junk

US scientists plan to use ground laser to shoot down space junk

The envisaged laser system will help clear space debris on the orbit and ensure the safety of satellites and rocket launches.

According to the report of Wired magazine in the United States, hundreds of thousands of space debris of various sizes are currently scattered in low Earth orbit. These space debris will pose a potential threat to rocket launches and satellite operations. Now a team of scientists is planning to use ground lasers to shoot them down.

The heat generated by the laser irradiation will evaporate a small part of the shell material on the surface of these space debris. These evaporated materials will generate weak plasma jets at the back of these space debris, which will slow down the operation speed of these space debris, and ultimately lead to They derailed and crashed into Earth's atmosphere to burn.

The paper on this project was published on the arxiv website on October 17. The co-author of the paper, Associated Photonics Engineer Claude Phipps, said: "In fact, what you did was create a piece. In laser-propelled rockets, these space debris decelerated and eventually crashed on this 'retro'.

Space debris is quite different, ranging from tiny debris to the entire abandoned satellite or upper class of rockets. Now that all of these wastes have accumulated over decades, they are reaching a certain critical point. Nowadays, space agencies around the world have suddenly discovered that the density of space debris in low-Earth orbit has reached a level where collisions are almost inevitable, and even more terrible is that each such collision event will generate more New debris.

This scenario was already proposed by the space physicist Donald Kessler as far back as 1978. At the time, he pointed out that humanity will face such a scenario in the future, that is, satellites operating in orbit will have to worry about the threat of space junk. These space junk will be able to penetrate the outer shell of satellites. Just two years ago, an American satellite collided with a scrapped Russian satellite over the Siberian region. This was the first large-scale space satellite impact incident. Earlier this year, astronauts on the International Space Station were asked to urgently enter the docked Soyuz escape spacecraft to be ready to evacuate, because ground observations revealed that there was a space debris likely to hit the International Space Station.

NASA has considered a variety of options to try to clear out excess garbage in space. The schemes they have considered can be varied, including the use of spacecraft to open large trawls and so on. Kessler revealed that, in fact, NASA had previously envisioned a laser cleaning program. At that time, NASA envisioned using a beam of medium-level laser light emitted from the ground to hit space debris and use laser photons to apply weak thrust to space. Garbage gradually decelerated. However, the effectiveness of this program will be limited to very lightweight space debris, and it will be incapable of dealing with the most dangerous and larger types of waste. Kessler was a senior scientist at NASA orbital debris research.

If we use more powerful lasers, such as 150 kilowatts, we should be able to take action on any size of space debris. Those small pieces of trash (less than 3 inches in size, about 7.6 centimeters in size) will decelerate decelerating and fall into the atmosphere and burn down under the action of lasers. Those larger types of trash need careful planning to lead them to crash safely in the surface ocean.

If the use of a terrestrial laser can solve the problem, it will save the need to launch spacecraft to space. Such a mission will cost hundreds of millions of dollars. According to the calculations of the Phipps team, the laser destruction program uses approximately hundreds of dollars for the destruction of small pieces of rubbish, and about US$1 million for large pieces of rubbish destruction.

However, Kessler also warns that such technologies also need to be used with great care. He said: "If you are not careful, you may be exposed to the wrong part of the satellite, or you may let the satellites overheat and cause explosions."

However, Phipps is full of confidence. He believes that only a specially designed 10-meter aperture telescope can take up the tracking of these space debris, and accurately determine the location of the irradiation and irradiation program. The construction of such a large-scale telescope, including a large 10-millimeter lens and related precision technology, is now readily available.

Perhaps the biggest criticism of this proposal is from the international community, because they will worry that such a powerful laser weapon may be used in the war to destroy the enemy's satellites. It is based on this political concern that the U.S. government’s policy on such plans is to reject it completely.

But Phipps is still very persistent. He has been working on the development of such a laser cleaning program since 1996. He believes that the construction of an ultra-large tracking and monitoring telescope should be the common responsibility of the international community. Basically half of the space debris is generated by the former Soviet Union and the United States, so they should naturally assume the responsibility of cleaning up. Other aerospace powers that can contribute to this area should also join in. He said: "As long as we carry out appropriate international cooperation, I think no one will worry about this laser will be used as a weapon." (Breakfast)