In two weeks, NASA will usher in a new era for the solar system.
The milestone comes courtesy of the Double Asteroid Redirection Test (DART) mission, which launched last fall. On September 26, DART will collide head-on with a small asteroid, the rare case where the destruction of a spacecraft is the desired outcome. The mission is in the name of planetary defense, which seeks to protect land of any potential asteroid impacts; scientists expect it to be dangerous asteroid threaten the planet in the future, a mission like DART could prevent disaster.
“These objects move through space, and of course they’ve marked the Moon, and over time, they’ve also had major impacts on Earth, they’ve affected our history,” said Thomas Zurbuchen, associate administrator of NASA science, during a press conference held on Monday. (September 12).
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“A number of new missions we’ve launched are helping us understand and quantify these threats in an unprecedented way,” added Zurbuchen. “DART is a first mission to try to actually take out a threat object in a direct experiment.”
Scientists have identified and mapped the orbits of nearly 30,000 asteroids whizzing around the solar system in Earth’s neighborhood. All of these space rocks either never collide with Earth or are so small that if they did, they would burn up harmlessly. earth’s atmosphere. Still, it’s possible that an asteroid impact in the future could damage Earth, and planetary defense experts want to be prepared.
The theory goes that if scientists ever spotted an asteroid on a collision course with Earth, an impactor probe could realign the space rock’s orbit, ensuring it crossed Earth’s path when our planet was at a safe distance. But scientists do not want to work only from theory if the situation arises.
This is where the dramatic destruction of DART comes into play. The spacecraft will collide with a small asteroid called Dimorphos, which like clockwork orbits a larger near-Earth asteroid called Didymus every 11 hours and 55 minutes. (Neither asteroid poses any threat to Earth, and DART will not change that.) DART’s impact should adjust Dimorphos’ orbit, cutting its circuit by perhaps 10 minutes.
Scientists on Earth will spend weeks after the impact measuring the actual change in the moon’s orbit to compare it with their predictions. The work will refine scientists’ understanding of how asteroids respond to impactors and help fine-tune future missions to the required amount of orbital change.
“This is not just a one-time event,” said Nancy Chabot, DART’s coordination officer at Johns Hopkins University’s Applied Physics Laboratory in Maryland, which is leading the mission, during the press conference. “We want to know what happened to Dimorphos, but more importantly, we want to understand what this means so we can apply this technique in the future.”
While the stakes are low compared to any scenario that would motivate an actual asteroid deflection mission, the difficulty is the same.
“This is incredibly challenging,” Evan Smith, the mission’s deputy system engineer, said during the press conference, noting that the spacecraft will only be able to see Dimorphos itself for about an hour and a half before impact. “This is an initial course, so let’s go for success this time.”
What if something doesn’t go as planned? Mission personnel are pretty sure that as long as the spacecraft reaches its target, there should be something to see.
“If DART collides with Dimorphos and then you see no orbital period change, that would be exceptionally surprising,” Chabot said. “Just the amount of thrust that DART is providing by itself from the weight of the spacecraft hitting Dimorphos is enough to change its orbit in a measurable way.”
Losing the moon is still a possibility, but that’s the point of DART: to find out what aspiring planetary defenders need to know if they ever want to launch a real asteroid deflection mission.
“This will give us all confidence that the deflection technology could work in the future,” Andrea Riley, a NASA program executive who works with the agency’s Planetary Defense Coordination Office, said during the conference in press “If it fails, it still provides a lot of data. This is a test mission. That’s why we do tests; we want to do it now and not when there’s a real need.”
Email Meghan Bartels at mbartels@space.com or follow her on Twitter @meghanbartels. Follow us on Twitter @spacedotcom yen Facebook.