Remember last September when NASA crashed a spaceship into an asteroid to see what would happen? Well, an investigation team led by the Johns Hopkins Applied Physics Lab (APL) released a paper confirming that the successful Double Asteroid Redirection Test (DART) mission wasn’t just for fun; it proves that humanity can deflect asteroids and also actually save the planet.
NASA outlined the conclusion in a new blog post on Wednesday, explaining that the “kinetic impactor” technique, which APL writer Ajai Raj jokingly defines as “smashing a thing into another thing,” could indeed be used as an effective means of planetary defense.
“These findings add to our fundamental understanding of asteroids and build a foundation for how humanity can defend Earth from a potentially hazardous asteroid by altering its course,” Nicola Fox, NASA’s associate administrator for the Science Mission Directorate, stated in the agency’s blog post. The findings are part of a series of four papers published in Nature describing the results and takeaways of the DART mission.
The September 26th mission last year altered the orbit of asteroid moonlet Dimorphos by 33 minutes, as calculated in one of the papers. The DART spacecraft launched debris from the asteroid at the impact point, known as ejecta. The recoil effect of the debris was found to have contributed more to the asteroid’s momentum change than the impact itself.
Authors at APL reported in another paper that asteroids like Dimorphos with a diameter of around half a mile can be successfully deflected by this method and not need an advance reconnaissance mission. But the writers warn that earthlings will need a sufficient warning time, ideally decades in advance or several years at a minimum, to mitigate such a threat.
All in all, there’s a lot of optimism about humanity’s ability to protect itself from giant space rock bullies. And we’ll have to hand off the recipe for how to do this whole kinetic impactor thing to the next generation, because according to the APL: “no known asteroid poses a threat to Earth for at least the next century.”