Here’s How NASA’s DART Spacecraft Forever Deflected Planetary Defense

The NASA Dart operation involved ramming a spacecraft into an asteroid to divert it. It had a more significant impact than most scientists had anticipated.

The orbital period of asteroid Dimorphos around its bigger companion Didymos was reduced by 32 minutes due to a head-on collision with the Dart probe on Sept. 26. This information was released on Tuesday by the US space agency.

With this achievement, humans successfully altered a celestial object's course for the first time. Deflection technology that might shift an asteroid's course to avoid a catastrophic collision with Earth was also shown for the first time.

"Well, well - that meeting between Dimorphos & the #DARTmission turned out to be a much more moving experience for the little asteroid than anticipated," said Mark McCaughrean, senior science adviser for the European Space Agency, NASA's partner in the project on Twitter.

How NASA's Dart Impact Changed Planetary Defense Test

The Didymos Reconnaissance and Asteroid Camera for Optical Navigation camera was the only instrument on board the DART spacecraft, which launched in November 2021 and cost roughly $314 million (DRACO). The spacecraft then traveled to Dimorphos, an asteroid that orbited a bigger asteroid called Didymos once every 11 hours and 55 minutes and was thought to be around 525 feet (160 meters) broad by astronomers.

DART made a dramatic entry into the solar system on Sept. 26. It traveled at 14,760 mph (23,760 kph) and sent one photograph to Earth every second until it collided with Dimorphos at a distance of 11 million miles (7 million kilometers).

That was the mission's first accomplishment on its own. Still, the evening also indicated that it might be beyond all expectations.

Scientists received their first excellent look at Dimorphos when DART sent images back to Earth in the waning minutes because from Earth, the small moon and the bigger Didymos seem like a single dot in a field of stars. The photographs first revealed a rock formation that resembled an egg, then a field of stones, gravel, and dust.

Tom Statler, the DART program scientist, could gauge the mission's success based only on that information.

"When I saw Dimorphos come into view and when I saw there was not a single crater on it and there were a lot of what appeared to be loose rocks - and this was a non-scientific, by-eye measurement - I looked at it, and I said, 'This is not going to be 73 seconds,' he said (via Space.com).

What's Next for DART Mission

The mission scientists will examine more telescopic observations and images taken by Dart's camera shortly before impact and by LiciaCube. This Italian satellite traveled with Dart to the pair of asteroids 11 million kilometers from Earth in the coming weeks.

The European Space Agency will launch the Hera mission in 2024 to conduct a thorough post-impact study of Dimorphos and Didymos. According to experts, there is no chance that the collision with the Earth will push the asteroid.

Following the findings of the deflection, NASA posted the following on Twitter: "Remember: DART is a test and there are no known asteroid threats to Earth."

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