It’s Science Wednesday! A few weeks ago, we heard about the DART (Double Asteroid Redirection Test) mission that managed to successfully impact its target asteroid, Dimorphos. It was a first-of-its-kind mission, demonstrating usage of asteroid deflection technology in case of a future threat to life on our planet.
Before the encounter, Dimorphos’ orbital period around the larger asteroid, Didymos, was 11 hours, 55 minutes. After impact, the orbit time shortened to 11 hours, 23 minutes, with an uncertainty of +/- 2 minutes. NASA’s success threshold was a change of at least 73 seconds. So, surpassing this benchmark by more than 25 times is a significant achievement!
Beyond the changes to the orbit, scientists are also interested in the efficiency of the transfer of momentum when DART hit the asteroid, traveling at a speed of 14,000 miles (22,350 km) per hour. They will study all the rocks that got displaced and launched into space by the impact. The recoil from this blast of debris enhanced DART’s push against Dimorphos – but by how much? To fully understand the recoil requires more information on the asteroid’s physical properties, including how strong or weak the rock is.
In some good and confirmed news, neither asteroid in the double-asteroid system pose any hazard to Earth post-DART’s controlled collision with Dimorphos.
The more we learn about the details of this impact, the better off we will be should the need ever arise to deflect an Earth-bound asteroid.