What we learned from NASA's asteroid-smashing DART mission

NASA smashed a spacecraft into an asteroid successful 2022 successful an effort to determination it, and the collision had much effect connected the asteroid’s orbit than predicted. An investigation of the smash-up and its aftermath has revealed why, and the results could thatch america much astir however to support our satellite from asteroids.

The Double Asteroid Redirection Test (DART) sent a probe careening into a tiny asteroid called Dimorphos, which orbits a larger 1 called Didymos. Five groups of researchers person present analysed antithetic aspects of the collision, which pushed Dimorphos person to Didymos, making each orbit astir 33 minutes shorter than earlier the smash – much than 25 times the alteration successful orbital play required for the ngo to beryllium considered a success.

That was helped by the information that DART was close connected target. “The spacecraft deed precise adjacent to the centre… of Dimorphos, which is wherever you privation to deed successful bid to maximise the momentum transfer,” says Carolyn Ernst astatine Johns Hopkins University successful Maryland.

But possibly much importantly, parts of the asteroid flew disconnected aft the collision, giving it an other push. “People whitethorn deliberation of the DART ngo arsenic a reasonably straightforward experimentation that is akin to playing billiards successful abstraction – 1 coagulated spacecraft impacts into 1 coagulated asteroid,” says Cristina Thomas astatine Northern Arizona University. “However, asteroids are acold much analyzable than conscionable a coagulated rock.”

Most asteroids – including Dimorphos, arsenic it turns retired – are rubble piles tenuously held unneurotic by gravity. So erstwhile DART deed it, betwixt 0.3 and 0.5 per cent of the asteroid’s wide came flying disconnected successful a immense plume of ejecta. This plume amplified the momentum transferred from the spacecraft to the asteroid by a origin of 3.6.

If we ever request to usage thing similar DART to deflect an asteroid that is heading towards Earth, knowing that other propulsion volition beryllium crucial. “Ejecta is going to springiness a larger propulsion to the asteroid than the spacecraft itself, truthful that means successful the aboriginal if we person to usage this exertion to divert an asteroid from hitting Earth, past we don’t needfully request a immense spacecraft,” says Jian-Yang Li astatine the Planetary Science Institute successful Arizona.

The plume of ejecta besides puts Dimorphos successful a unusual class of asteroids called active asteroids, which person tails similar comets. It has agelong been thought that these tails mightiness signifier from collisions with smaller abstraction rocks, and DART has shown that thought to beryllium a bully fit. “We tin present truly nail down what’s going connected with progressive asteroids, and that helps america fig retired what they’re made of, which ties backmost to the commencement of the star strategy erstwhile they formed,” says Ariel Graykowski astatine the SETI Institute successful California.

After DART, we cognize that we tin alteration the trajectory of a tiny asteroid similar Dimorphos, but each asteroids are antithetic truthful we can’t beryllium definite that a akin ngo would enactment connected thing that mightiness beryllium headed our way. “I deliberation the champion mode to use what we’ve learned is to bash it again connected thing bigger,” says Graykowski. “We request to present instrumentality what we cognize astir however squishy the asteroid ended up being, however overmuch worldly came disconnected of it, however overmuch we were capable to determination it, standard it up and bash it again.”

Journal references: Nature, DOI:10.1038/s41586-023-05805-2, DOI:10.1038/s41586-023-05810-5, DOI:10.1038/s41586-023-05811-4, DOI:10.1038/s41586-023-05878-z, DOI:10.1038/s41586-023-05852-9

Sign up to our escaped monthly Launchpad newsletter for a voyage crossed the postulation and beyond

Topics: