The asteroid Didymos has a small moon (satellite), Dimorphos. Didymos has a diameter of 780 m and Dimorphus is only 160 m in diameter. Dimorphos is almost the size of the Colosseum in Rome, Italy, the size of a football field.
Space X, which carried the DART (Double Asteroid Redirection Test) spacecraft at Vandenberg Space Force Base in California at 6:20 am (3:20 pm Korean time) on the 24th by NASA Launch a Falcon 9 rocket. The goal is to collide the Dart spacecraft with Dimorphos at a speed of 6.6 km/s (23,760 km/h). To put it bluntly, it looks like an asteroid the size of a football field and a dart spacecraft the size of a large refrigerator.
After launch, the dart will escape Earth’s gravity and orbit around the sun, and will collide with Dimorphus at a distance of 10.78 million km from Earth in September next year.
The goal is not to destroy the asteroid, but to see the possibility of changing the orbit of an asteroid that might one day orbit the Earth by orbiting it by one degree. This is what happened in the sci-fi movies ‘Armageddon’ and ‘Deep Impact’. About ten days before the impact, the LiciaCube, a small Italian-made satellite camera, is detached from the dart to observe the moment of impact and changes thereafter. It is said that if the orbit is corrected by about 1 degree, it can be confirmed by an astronomical telescope on Earth in a few weeks or months.
Even a lump of space debris several hundred meters in size can inflict enormous damage if it collides with the Earth that a continent itself is devastated. No asteroids in the solar system are currently observed to pose a hazard to Earth. In 2005, the U.S. Congress mandated that the solar system search for Earth-like asteroids, and more than 90% were found to pose no significant threat to Earth. However, learning how to defend the Earth is necessary, so it is the first time experimenting in outer space.
Kelly Fast, NASA’s director of planetary defense cooperation, said, “The dart is trying to change the orbital period of Dimorphus by a very small amount. “What was really required throughout this event was the discovery of the asteroid at a much earlier point in time.”
The dart mission costs $325 million (about 386.3 billion won). Even if an object the size of Dimorphus collided with Earth, it would be several times more powerful than a nuclear bomb, and could destroy a densely populated area and take millions of lives. Even if it is more than 300m in diameter, the damage area is widened to the size of a continent. If it were 1 km in diameter, the whole world would be in danger.
Lim Byung-seon, Executive Director, Peace Research Institute bsnim@seoul
co.kr
