DART mission: how NASA hit the nail on the head

Small asteroids hit Earth’s atmosphere every day. It’s the big ones we care about, as shown in Hollywood extravaganzas like “Armageddon” and “Don’t Look Up.”

“I’ve never been able to sit still watching asteroid movies and not just want to get up and walk away,” said MIT professor Richard Binzel. Besides writing the book on asteroids, he also invented the Torino Scale, a 10-point danger scale for asteroids.

“All objects we know of today reside at zero or one, which simply means that they are so small that they do not matter, or that we know for certain that there is no has no possibility of impact,” Binzel said.

Correspondent David Pogue asked: “Sounds like asteroids annihilating humanity shouldn’t be high on our list of worries?”

“The asteroids that wipe out our humanity don’t keep me up at night, unless I’m at the telescope studying them!” Binzel burst out laughing.

But there have been dangerous asteroid strikes. In 2013, a 60-foot rock from outer space injured 1,500 people and damaged thousands of buildings in Russia.

NASA thinks it’s time to prepare for the next one.

But probably not the way an asteroid was treated in “Deep Impact” – by blowing it up.

“It probably is not the best way to do it,” said NASA’s Elena Adams. “Because if you blow up an asteroid, you create a lot of pieces. And these pieces will always go in the same direction. The easiest thing to do is change its direction slightly, and then it will completely miss the Earth.”

Adams is the lead engineer for the DART mission, a joint venture between NASA and the Johns Hopkins Applied Physics Laboratory. It took off last November with the aim of altering the trajectory of an asteroid by crashing into it.

DART stands for Double Asteroid Redirection Test because its target is, in fact, a double asteroid orbiting the sun. The main asteroid, called Didymos, is about half a mile in diameter. It has its own moon, and it’s our target.

The goal is to bring the orbit of the moon of Didymos slightly closer. “Just a little nudge, a tap,” Adams said. “It’s like throwing a tennis ball at a 747. If it goes fast enough, you’ll move it. It’s a first test, can we really do it?”

As a bonus, the 1,200-pound spacecraft is a veritable science fair of tech tests that could be useful in future missions: super-lightweight solar panels that unfold; a new ion thruster; and a separate small camera satellite that DART carried in its pocket, the Italian Space Agency’s LICIACube, so that we could all enjoy the footage of the crash.

There’s even a new standalone computer, SMART Nav, that takes over when DART is too far away to control from Earth.

“It’s the crown jewel of the spacecraft,” Adams said. “So, let’s see if it works well.”

DART is the first major project of a NASA department called the Planetary Defense Coordination Office.

NASA’s Lori Glaze leads the division that oversees planetary defense.

“The ones that really are the end-of-civilization-sized asteroids, we know; we’ve found 99% of them already,” Glaze said. “The smaller ones that could have regional damage, there are some that we don’t know about. So we’re already building the next telescope, a space telescope called Near-Earth Object Surveyor (NEO Surveyor), to search the sky 24 hours a day.”

Last Monday, 10 months after liftoff, DART approached its target: seven million kilometers from Earth, traveling four kilometers per second, towards a lunar asteroid that no one has ever seen.

And to make things even more difficult? Adams said, “We don’t know what it’s made of either, we don’t know its shape. How do you hit something you don’t even know the shape of?”

19 minutes from impact, you could see the moon Dimorphos for the first time.

NASA DART hit the bullseye.

In a few weeks, NASA will calculate how much this small moon has moved. But we already know what happened to Elena Adams’ $325 million baby. “It’s like a Ferrari, isn’t it? It’s just a nice piece of equipment, and then the whole point is going crashing into a rock!” she laughed.

“It’s sad!” said Pogue.

“But also a bit glorious!”

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Story produced by Julie Kracov. Publisher: Mike Levine.