The NASA probe that deliberately hit an asteroid last September scattered 1,000 tons of rock into space, which will help the US space agency with more information on the study of this type of material.
The main objective of the Dart mission (acronym for Dart Redirection Test) Asteroid Duplo) had to put into practice the first experiment to demonstrate a deflection technique, i.e. deflecting an asteroid to protect the planet.
Two asteroids that orbit the Sun and occasionally approach Earth have been the targets of the NASA🇧🇷 They pose no threat to our planet, but their proximity made them prime candidates for testing.
The larger of the two asteroids, Didymos, has a diameter of 780 meters. Around it orbits a smaller natural satellite, called Dimorphos, which was the object hit by the space probe.
The scientists working on the project were even able to evaluate the effectiveness of the impact. The force transferred to Dimorphos was 3.6 times greater than if the probe had simply been absorbed by the asteroid and produced no ejecta.
“If you blast the material a little bit off target, there will be a recoil force,” explained Andy Cheng, mission scientist and Johns Hopkins University Applied Physics Laboratory (JHU-APL).
“The result of that recoil force is that you give the target more momentum and end up with a bigger deflection.”
“If you’re trying to save the Earth, that makes a big difference,” he said, as it would either increase the time available to mount a defense or reduce the size of projectile needed.
The Double Asteroid Redirection Test took place about 11 million km from Earth.
The NASA satellite, the size of a refrigerator, crashed at 22,000 km/h into the 160-metre-wide Dimorphos, destroying itself.
Before impact, the time it took for Dimorphos to orbit the 780-meter-wide Didymos was 11 hours and 55 minutes.
Subsequent observations by the telescope indicated that this orbital period was reduced to 11 hours 23 minutes, a 32-minute change.
“It was worth it,” said Andy Rivkin, head of Dart’s investigation team.
The 1,000 tons of space rock ejected, which he likened to “six boxcars of rock,” are just an initial estimate.
“The studies are still ongoing, it may be that this number is minimal; it could be double, it could even be 10 times more, according to some estimates.”
The ejecta is only a fraction of the total mass of Dimorphos, which is about 5 million tons.
However, the impact caused a big “mess” and telescopes continue to monitor the debris as it travels tens of thousands of kilometers away from the asteroid.
The study of the Didymos-Dimorphos system before and after the impact has revealed a lot about the properties of the two asteroids.
They are very similar to a type of meteorite that frequently falls to Earth called a common chondrite, said Cristina Thomas of Northern Arizona University.
The President of the United States, Joe Bidendescribed the Dart mission as one of the US space agency’s three big successes in 2022. The other two are the recent Artemis-1 mission to the Moon and the first images from the new James Webb Space Super Telescope.
NASA Dart program scientist Tom Statler agrees.
“The Dart has been a huge success. Of course, a successful mission doesn’t automatically guarantee that Earth is safe from anything that might encounter us. But the Dart is truly a giant step toward our goal of making asteroid impacts most avoidable. on earth.”
– This text was published in https://www.bbc.com/portuguese/internacional-64006905
