Although Dimorphos resembles many other near-Earth asteroids, the DART team selected it as a target because it is a base member of a pair of asteroids. It’s called a “moonlet,” and it orbits Didymos, its larger counterpart, like the hands of a clock every 11:55 a.m. and 55 minutes. DART will hit Dimorphos at an angle of about 17 degrees from its orbit, and the scientists plan to measure how much it will shift its orbit. In other words, they could easily compare its motion with that of another nearby object. If they had chosen to strike a lone asteroid, the slight deviation from its orbit would not be apparent for many years, until it had passed by Earth. But thanks to the proximity of its counterpart, any change to Dimorphos’ orbit could be identified within days.
“It’s really a smart and ingenious way, and it saves money. And it’s safe, too: You’re moving this moon a little closer to the asteroid it’s already orbiting,” said Chabot. She and her team hope DART will shorten the asteroid’s orbit by 5 to 15 minutes, so that it could take just 11 hours and 45 minutes to circumnavigate Didymos. NASA will consider a gap of 73 seconds or so as a successful mission.
This pair of asteroids will be close enough to make accurate telescope measurements on Earth until March 2023. After that, they will travel farther, as part of their path around the sun passes. beyond the orbit of Mars. While asteroids look like a single bright spot from this distance, scientists will be able to measure how often the brightness of reflected sunlight emitted by Didymos dims – a quantity for the period in the orbit of Dimorphos.
These asteroids, like many other asteroids and some meteorites – space rocks that enter Earth’s atmosphere – are not as dense and solid as billiard balls. They are probably loose masses of rock, gravel, and ice that are held together in an arrangement known as a “rubble pile”, with a rock composition similar to that of asteroids. Ryugu and Aeros, and with Meteor explodes over Chelyabinsk, Russia, in 2013. In fact, the moon Dimorphos could have formed simply by orbiting Didymos’ surface. If Dimorphos were a piece of debris, the DART impact could create a crater, rather than hurling debris and impacting the asteroid significantly. But that uncertainty is one of the reasons for undertaking the task.
For a more detailed examination of the crash scene, the European Space Agency Hera next incoming task. The spacecraft is scheduled to launch in 2024. When it approaches the asteroid duo in 2026, the optical camera, lidar instrument, infrared scanner, and two CubeSat sidebars will create detailed maps. on the surface and structure of Dimorphos.
If a dangerous asteroid is indeed heading towards Earth, crashing a spacecraft — or “a kinetic impact” — it is just a tool humans use. NASA, ESA and other space agencies are also exploring other approaches, like locating a spacecraft near a “gravity tractor” to pull it in a different direction or detonate an explosion. nearby nuclear explosion to force it away. (Nuking the asteroid itself is in danger of failure, as that could turn it into much Lori Glaze, Director of NASA’s Planetary Science Division, said at a news conference Sunday.
