Mark Megahan
NASA’s big Double Asteroid Redirection Test went exactly as planned on September 26. Uncle Sam fed millions of dollars worth of quarters into the planetary security project but Tuesday was game over for DART, as it smashed itself to smithereens against Dimorphos.
Asteroid impact as planned
NASA intentionally crashed a satellite on Monday, and did it perfectly. The Double Asteroid Redirection Test was part of the groundwork for a planetary defense project. Scientists needed to measure the effect to determine if that method is worth sinking a whole lot more money into, before it becomes a boondoggle.
If they can nudge a little hunk of rock enough to make a difference, then we can scale the project up enough to deflect a real threat.
Didymos is a double asteroid system just perfect for target practice. The smaller of the two gravity linked objects, Dimorphos is just about a half-mile wide. This particular system isn’t any threat to earth. It just happened to be handy.
Because half the people on Earth were curious about the mission, NASA thoughtfully beamed the final hour or so live to the public. The spacecraft was taking snapshots at the rate of one per second until it hit the beach. Literally.
Grey and rocky
Engineers knew for certain that they hit their target because the camera went dead. Otherwise, it would have flown right on by taking snapshots of black and empty deep space.
Engineers expected to see a grey, rocky asteroid but everyone was taken by surprise when the surface appeared in amazing detail. Impact happened around 7:15 p.m. ET after a 6 million mile journey.
Along with the craft which smashed into Dimorphos was a second LICIACube asteroid imaging satellite. That one returned “images from above the impact, which show the impact crater left by DART.”
They tested it’s cameras and ended up with a shot of “a crescent Earth and the Pleiades star cluster.” What looks like rocks you can hold in your hand are actually boulders.
Back in 2003, the Didymos pair paid Mother Earth a little visit, waving from 5 million miles away. That’s a whole lot further away than our Moon.
