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.[0] The DART spacecraft collided with a small asteroid moon called Dimorphos, which orbits a larger asteroid called Didymos.[1] 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.[2]
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.”[3]
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.[4] 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.[5] This correspondence suggests that collisions can cause asteroids to become active.[5]
The European Space Agency’s Hera mission is scheduled to launch in October 2024 and arrive at Didymos two years later.[6] Hera is tasked with thoroughly investigating the Didymos-Dimorphos system, including the crater created by DART's impact.[7]
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.[8] 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.[9]
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.[10] 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.[11]
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
