In two weeks, NASA will open a new era for the solar system.
The milestone comes courtesy of Double Asteroid Redirection Test (DART) Mission that started just last fall. On September 26, DART will smash headfirst into a small asteroid, the rare occasion when spacecraft destruction is the desired outcome. The mission is in the name of planetary defense that seeks to protect Earth from possible asteroid impacts; Scientists hope this should be dangerous asteroid threaten the planet in the future, a mission like DART could avert catastrophe.
“These objects are hurtling through space and of course they have scarred the Moon and over time also had a major impact on Earth and influenced our history,” Thomas Zurbuchen, NASA’s deputy administrator for science, said during a news conference Monday (Jan. September).
Related: NASA’s DART asteroid impact mission explained in pictures
“A number of new missions that we have established are actually helping us to understand and quantify these threats in an unprecedented way,” added Zurbuchen. “DART is a first mission attempting to truly eliminate an object of threat in a direct experiment.”
Scientists have identified and mapped the orbits of nearly 30,000 asteroids orbiting the solar system near Earth. All of these space rocks either never intersect with Earth, or are so small that if they did, they would burn up harmlessly earth atmosphere. Still, it’s possible that an asteroid impact could damage Earth in the future, and planetary defense experts want to be prepared.
The theory states that if scientists ever spot an asteroid on a collision course with Earth, an impactor probe could reorient the space rock’s orbit to ensure it crosses Earth’s orbit when our planet is at a safe distance. But scientists don’t just want to work from theory when the situation arises.
This is where the dramatic destruction of DART comes into play. The spacecraft will crash into a small asteroid called Dimorphos, which is orbiting like clockwork a larger near-Earth asteroid called Dimorphos Didymos every 11 hours and 55 minutes. (Neither asteroid poses a threat to Earth, and DART will not change that.) DART’s impact should adjust Dimorphos’ orbit, shortening its orbit 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 tailor all future missions to the level of orbit changes needed.
“This is not just a one-time event,” said Nancy Chabot, the DART coordinator at Johns Hopkins University’s Applied Physics Laboratory in Maryland, who is leading the mission, during the press conference. “We want to know what happened to Dimorphos, but more importantly, we want to understand what it means for the potential application of this technique in the future.”
While the stakes are low compared to any scenario that would motivate a real asteroid distraction mission, the difficulty is the same.
“This is an incredible challenge,” Evan Smith, the assistant mission systems engineer, said during the press conference, noting that the spacecraft can’t see Dimorphos itself until about an hour and a half before impact. “This is a par one course so let’s hit the shot this time.”
And if something doesn’t go according to plan? Mission personnel are fairly confident that as long as the spacecraft reaches its destination, there should be something to see.
“If DART collides with Dimorphos and then you don’t see a change in orbital period, that would be exceptionally surprising,” Chabot said. “Just the amount of momentum that DART imparts from the weight of the spacecraft impacting Dimorphos alone is enough to measurably shift its orbit.”
Missing the small moon is still a possibility, but that’s sort of the point of DART: finding out what wannabe planet defenders need to know if they’re ever going to launch a real asteroid diversionary mission.
“This will give us all confidence that deflection technology could work in the future,” Andrea Riley, program director at NASA who works with the agency’s Planetary Defense Coordination Office, said during the press conference. “If it misses, it still provides a lot of data. This is a test mission. That’s why we test; we want to do it now and not when there is an actual need.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghan bartels. follow us on twitter @spacedotcom and further Facebook.
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