A powerful bounce effect has magnified NASA’s asteroid deflection experiment

A composite image of the Didymos-Dimorphos system taken on November 30, showing the tail of the new projectile.

Scientists continue to look at the results of NASA’s amazingly successful DART test to deflect a harmless asteroid. As the latest results indicate, the recoil from the explosion of debris emitted by Dimorphos after the impact was significant, adding to the spacecraft’s impact on the asteroid.

The refrigerator-sized NASA spacecraft collided with 535-foot (163-meter) Dimorphos on Sept. 26, shortening its orbit around its larger partner, Didymus, by 33 minutes. This is the equivalent of tens of feet, demonstrating the feasibility of using kinetic stimuli as a means of deflecting menacing asteroids.

Read more

A startling side effect of the test was the huge, intricate plumes that spewed out from the asteroid after the impact. The Didymus-Dimorphos system, located 7 million miles (11 million km) from Earth, even sprouted a long tail in the experiment’s wake. DART, short for the Double Asteroid Redirection Test, had a profound effect on Dimorphos, releasing a surprising amount of debris, or “projectiles” in the parlance of planetary scientists.

Dimorphos, as we’ve learned, is a rubble pile asteroid, as opposed to a dense, tightly packed, rocky body. This undoubtedly contributed to the increase in the amount of debris ejected, but scientists weren’t quite sure how much debris the asteroid had thrown up as a result of the impact. Preliminary results presented Thursday at the American Geophysical Union fall meeting in Chicago shed new light on this and other aspects of the DART mission.

Not only did DART fire tons of projectiles, but it also created a ricocheting effect that propelled the asteroid in the desired direction, Andy Rifkin, lead of the DART investigation team, explained at the meeting. “We got a lot of money for the money,” he told BBC News.

In fact, had Dimorphos had a more compact body, the same level of recoil probably wouldn’t have occurred. “If you bomb material off target, you have a kickback force,” explained DART mission scientist Andy Cheng of the Johns Hopkins University Applied Physics Laboratory, who also spoke at the meeting. The resulting bounce is similar to letting go of a balloon. As the air rushes out, it pushes the balloon in the opposite direction. In the case of Dimorphos, the ejecta stream was the air leaving the balloon, which similarly propelled the asteroid in the opposite direction.

Planetary scientists are beginning to get a sense of how much debris has been displaced. DART, which was traveling at 14,000 mph (22,500 km/h), struck hard enough to spill over two million pounds of material into the void. That’s enough to fill about six or seven rail cars, NASA said in a statement. That estimate may in fact be low, Rifkin said at the meeting, with the true number possibly ten times higher.

The scientists set the DART’s momentum factor, known as “beta,” to a value of 3.6, which means that the momentum imparted to Dimorphos was 3.6 times greater than a collision event that did not result in an ejected plume. “The result of that recoil force is that you put more momentum into the target and you end up with a bigger deflection,” Cheng told reporters. “If you’re trying to save the Earth, it makes a huge difference.”

That’s a good point, because those values ​​would set the criteria for an actual mission to legitimately deflect a dangerous asteroid. Cheng and his colleagues will now use these results to infer beta values ​​for other asteroids, a task that will require a deeper understanding of the object’s density, composition, porosity, and other parameters. Scientists also hope to find out the degree to which DART’s first strike moved the asteroid and how much it moved due to the bounce.

The amplifiers also produced another character—a long tail, or output shaft, that formed in the aftermath of the impact. According to Rifkin, Dimorphos sprouted a tail 18,600 miles (30,000 km) long.

“The asteroid impact was just the beginning,” said Tom Statler, DART program scientist and presenter at the meeting, in the statement. “Now we’re using the observations to study what these objects are made of and how they formed — as well as how to defend our planet in the event of an asteroid heading our way.”

More from Gizmodo

Sign up for the Gizmodo newsletter. For the latest news, Facebook, Twitter and Instagram.

Click here to read the full article.

#powerful #bounce #effect #magnified #NASAs #asteroid #deflection #experiment

Leave a Reply

Your email address will not be published. Required fields are marked *