NASA’s DART Mission Redirects Dimorphos’ Orbit and Activates Asteroid – Captured by the Hubble Space Telescope
In September 2022, NASA launched its Double Asteroid Redirection Test (DART) mission to demonstrate a technique for deflecting asteroids on a collision course with Earth. The DART spacecraft collided with a small asteroid moon called Dimorphos, which orbits a larger asteroid called Didymos. Although neither asteroid posed a hazard to Earth, they were similar to the celestial bodies that may one day come close enough to put the planet in danger.
The collision with Dimorphos resulted in a 33-minute decrease in its orbit, reducing its orbital period around its parent asteroid, Didymos, to less than 11 and a half hours. The change is significantly greater than had been expected, as pre-impact, researchers anticipated the impact to shorten Dimorphos' orbit by only about 10 minutes. Tony Farnham, co-author of the study, stated “in other words, the ejected material acted as a jet to push the moon even further out of its original orbit.”
The impact from the collision with Dimorphos was observed by several telescopes, liberating debris which formed a tail stretching more than the 1,500 kilometers. For around three weeks, the team used the Hubble Space Telescope to observe the tail and noticed that its shape is comparable to that of “active asteroids”, which have a trajectory like an asteroid and a tail similar to comets. This correspondence suggests that collisions can cause asteroids to become active.
The European Space Agency’s Hera mission is scheduled to launch in October 2024 and arrive at Didymos two years later. Hera is tasked with thoroughly investigating the Didymos-Dimorphos system, including the crater created by DART's impact.
In a paper headed by astronomer Jian-Yang Li of the Planetary Science Institute, a thorough examination was conducted of the ejecta – the material that was expelled from the asteroid due to the explosive collision. The ejecta formed a tail that trails behind the moonlet, and over the course of 18.5 days, the tail evolved into Dimorphos’ striking new tail.
The Hubble Space Telescope captured the event as it unfolded, stitching together images taken during a period that started more than an hour before the collision and ended October 8. In the clip, released by NASA on Wednesday, debris can be seen flying away from the asteroid, rotating pinwheel-shaped features becoming visible once the asteroid's orbit distorts the original cone shape of the debris.
0. “Hubble captures timelapse video of DART spacecraft impacting asteroid” New Atlas, 2 Mar. 2023, https://newatlas.com/space/hubble-timelapse-dart-spacecraft-impacting-asteroid
1. “NASA's Asteroid-Bashing DART Mission Was Wildly Successful” Scientific American, 1 Mar. 2023, https://www.scientificamerican.com/article/nasas-asteroid-bashing-dart-mission-was-wildly-successful/
2. “NASA's asteroid deflection test shaved 33 minutes off the rock's orbit” Daily Mail, 1 Mar. 2023, https://www.dailymail.co.uk/sciencetech/article-11808051/NASAs-asteroid-deflection-test-shaved-33-minutes-rocks-orbit.html
3. “New NASA DART data prove viability of asteroid deflection as planetary defense strategy” Phys.org, 1 Mar. 2023, https://phys.org/news/2023-03-nasa-dart-viability-asteroid-deflection.html
4. “Slam! Hubble sees strange changes in asteroid dust after DART collision (video)” Space.com, 1 Mar. 2023, https://www.space.com/hubble-space-telescope-dart-asteroid-collision-dust
5. “3Q: What we learned from the asteroid-smashing DART mission” MIT News, 2 Mar. 2023, https://news.mit.edu/2023/3q-what-we-learned-asteroid-smashing-dart-mission-0302
6. “NASA's DART Mission Changed the Course of Planetary Defense” Gizmodo, 1 Mar. 2023, https://gizmodo.com/nasa-dart-asteroid-mission-planetary-defense-1850070584
7. “DART's epic asteroid crash: What NASA has learned 5 months later” Space.com, 1 Mar. 2023, https://www.space.com/nasa-dart-asteroid-crash-what-nasa-learned
8. “NASA Slammed a Spacecraft Into an Asteroid And It Didn't Go Quite as Expected” ScienceAlert, 1 Mar. 2023, https://www.sciencealert.com/nasa-slammed-a-spacecraft-into-an-asteroid-and-it-didnt-go-quite-as-expected
9. “NASA's Asteroid Smashing Mission Was a Huge Success for Planetary Defense” Inverse, 1 Mar. 2023, https://www.inverse.com/science/was-dart-successful-nasa
10. “Nasa reveals Armageddon-style asteroid crash WORKED and could save us from future killer space rocks…” The Sun, 2 Mar. 2023, https://www.thesun.co.uk/tech/21566808/nasa-asteroid-save-us-from-killer-space-rocks
11. “Hubble Space Telescope captured ‘movie' of spacecraft slamming into asteroid” CBS News, 2 Mar. 2023, https://www.cbsnews.com/sacramento/news/hubble-space-telescope-captured-movie-of-spacecraft-slamming-into-asteroid