We’ve had several posts on September 26th’s DART mission—the one in which NASA crashed a small spacecraft into the asteroid Dimorphos at 14,000 miles per hour. The object was to perturb Dimorphos’s orbit around a larger asteroid, Didymos. (DART stands for “Double Asteroid Redirection Test”.) The perturbation was effected by transferring momentum from the DART spacecraft (which crashed in a satisfying cloud of dust) to Dimorphos.
The ultimate goal of this program is to see if we can deflect a comet or asteroid heading towards Earth, staving off the immense destruction that a collision could cause. And, judging by DART, it’s at least possible.
As usual, my old friend and former NASA employee Jim Batterson gives us the details:
Earth Global Defense Test Results (DART Experiment)
Jim “Bat” Batterson
When the NASA/APL (Applied Physics Lab) spacecraft successfully impacted the small asteroid, Dimorphos on September 26, some WEIT readers wanted to know when we would know if it achieved its full mission – an actual perturbation of Dimorphos’ orbit.
In the post-impact press conference later that day, the mission engineering leadership estimated that the answer would come in a couple of weeks or so as Earth-based telescopes took careful measurements of Dimorphus’ orbital path around its larger companion asteroid, Didymos. They were right! Yesterday afternoon, NASA held a press conference at NASA Headquarters in which mission leaders gave us the answer: the orbit of Dimorphos around Didymos changed significantly – from 11hrs 55min to 11hrs 23min – a 32 minute change.
Here’s the full press conference, an hour long:
The first 30 minutes comprises what I thought was a very informative presentation from three lead project scientists; the final 30 minutes consists of the scientists answering questions from the global press. They explain in pretty good detail how the orbital change was measured and what these results mean.
Here’s one last video that APL [Johns Hopkins Applied Physics Lab, which partnered in the venture] put out on a summary sheet. The 40-second video compresses the final pics from the DART spacecraft and is really exciting to me. The final frame before blackout due to collision is only 51 ft across, which means the bigger boulders are about ten feet across and the visible small rubble is a foot in size or even smaller. Incredible technology.
Click on the screenshot below to go to the summary sheet and video. This is the moment before impact: