Success! The DART Spacecraft Knocked an Asteroid Off-Orbit - Nerdist
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Success! The DART Spacecraft Knocked an Asteroid Off-Orbit

NASA may not need to recruit oil drillers in the event of an Armageddon-style asteroid after all. The agency crashed a spacecraft into an asteroid seven million miles from Earth, to test whether it’s a viable option to knock one off course. The camera onboard the DART spacecraft tracked the asteroid from a tiny speck into a specific target. It took some great detailed images as it hurtled into Dimorphos and then stopped transmitting. Other images came in from NASA’s other projects, including telescopes on Earth and in space. Within two weeks, the data was in and the DART mission was officially declared a success. The DART mission even shortened the asteroid’s orbit far more than expected.

The last frame of asteroid Dimorphos before DART spacecraft crashed into it

The DART Spacecraft Crashes Into an Asteroid

Dimorphos is only 530 feet long and orbits another asteroid called Didymos, which is 2,560 feet long, or about half a mile. In comparison, DART was only 62 feet with its solar panels unfurled. The asteroids are not headed for Earth. They are just out there minding their own business. But NASA decided to bonk into Dimorphos anyway to see what happens. The technical term for this spacecraft collision with an asteroid is a “kinetic impact.” The people who approved funding for this mission have either seen too many disaster movies or, you know, heard what happened to the dinosaurs.

New Images of DART Collision with an Asteroid

DART deployed a probe about a week in advance of the asteroid collision, and it was following along to capture photos. The first images from its two optical cameras, LUKE and LEIA, show a cloud of ejecta around Dimorphos, with Didymos in the foreground (below). The probe will continue to take photos of the post-collision crater and asteroids.

The asteroid Dimorphos is surrounded by clouds of dust after the DART impact with Didymos in the foreground
ASI/NASA

DART launched back in November using a SpaceX Falcon 9 rocket and impacted the asteroid Dimorphos at 14,000 miles per hour. Scientists monitoring the asteroid’s orbit after the DART spacecraft crashed into it confirmed that it changed Dimorphos’ orbit around Didymos, shortening it. One trip used to take 11 hours and 55 minutes and now only takes 11 hours and 23 minutes. Considering NASA was hoping to change the orbit by at least 73 seconds, the DART mission was 25 times more successful than expected!

Hubble Space Telescope gif of multiple images of the DART impact
NASA, ESA, Jian-Yang Li (PSI); animation: Alyssa Pagan (STScI)

Both the Hubble Space Telescope (above) and James Webb Space Telescope (below) were pointed at Dimorphos when the DART came for the asteroid and captured the impact. They also continue to capture images of the dust trail from the impact, which scientists will use to understand how much of DART’s momentum transferred to the asteroid.

Gif animation of multiple photos the James Webb Space Telescope took of the DART impact
NASA, ESA, CSA, Cristina Thomas (Northern Arizona University), Ian Wong (NASA-GSFC); Joseph DePasquale (STScI)

More About the DART Mission

In case you’re wondering why computer simulations aren’t taking care of this kind of planetary defense, fear not—they are. But you have to field test it at least once to see if your simulation is accurate. That’s essentially the plan here. The team on the International Space Station demonstrated how kinetic impacts affect bodies in space by tossing boxes at a floating astronaut standing in for the asteroid.

An infographic showing the decreasing orbit of one asteroid around another after impact from the DART spacecraft
NASA/Johns Hopkins APL

The DART spacecraft cost hundreds of millions of dollars, all so it could crash into an asteroid, but for a good cause, of course. It had aboard only a few instruments, enough to guide it to its target. The camera system is DRACO (Didymos Reconnaissance and Asteroid Camera for Optical navigation). How’s that for an acronym? It took some cool pictures along the way, including of Vega as well as Jupiter and some of its moons. 

A chart showing the DART spacecraft and asteroids in comparison to the pyramids and other well known structures
NASA/Johns Hopkins APL

Of all the ways life on Earth could get snuffed out, asteroid impacts are one of the scarier scenarios. Though the asteroid that killed the dinosaurs was about 100 times larger than Dimorphos, even small collisions can have disastrous results. That’s why NASA’s planetary defense project performed this test.

Here’s hoping we’re bucking that sci-fi trend where every disaster movie starts with people ignoring a scientist. 

Originally published September 26, 2022.

Featured Image: NASA

Melissa is Nerdist’s science & technology staff writer. She also moderates “science of” panels at conventions and co-hosts Star Warsologies, a podcast about science and Star Wars. Follow her on Twitter @melissatruth. 

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