In space, there are a lot of asteroids and meteorites that are out of orbit. Some of these meteorites will pass by the earth, some will enter the atmosphere, friction and fire, and be burned. Even if they fall to the ground, they are very small and have very little power. But there are also some planets, because of their large size or density, once they hit the earth, they will cause major disasters to the earth. In the history of the earth, there have been several large meteorite impact events, each of which is a catastrophic event, causing extinction.
At present, human science and technology have no good defense means against these asteroids and meteorites. Once they hit the earth, they can only do nothing. But scientists will not give up, nor can they give up the research on how to change the impact of meteorites on the earth, because it is observed that there is an asteroid flying towards the earth, and the high probability event will hit the earth. Once it hits, it may be destroyed It’s another dinosaur extinction. Of course, hundreds of years later, scientists still have time to work out effective methods.
Recently, NASA’s dual asteroid orbit test (DART) spacecraft has entered the preliminary design stage and is scheduled to be launched from earth in 2024.
Dart spacecraft is part of the international asteroid impact and yaw assessment (Aida) mission undertaken by the United States. Its mission is to change the orbit of a non threatening asteroid, so as to prove that when there is a large planet impacting the earth, the plan of changing the orbit of the planet is feasible.
According to the plan, the dart spacecraft will hit Didymos B at 3.7 miles per second – ten times the speed of a bullet. The planet, about 500 feet in diameter, is just about the size to pose a threat to earth, which is why scientists chose it. After the impact, scientists will observe on the ground whether and how its orbit changes.
“Dart spacecraft is the key to proving our ability to protect earth from planetary impacts in the future,” said Andy Cheng, CO director of dart research and at Johns Hopkins University’s Applied Physics Laboratory, which is responsible for building dart spacecraft. Because we don’t know much about the internal structure and composition of planets, we need to carry out impact experiments on a real asteroid. Launching dart spacecraft, we can impact a dangerous target to change its orbit, and show how to protect the earth with dynamic impact. “
Changing the orbit of an asteroid is the most effective and feasible way to avoid asteroid impact. However, the energy required for this impact is relatively large, and the impact vehicle and speed should be powerful. However, if we want to encounter a larger asteroid, the general impact can not change the orbit, and other measures are needed.