A First for Humanity Confirmed: NASA's DART Mission Slowed the Asteroid's Orbit (sciencenews.org)
- Reference: 0180926020
- News link: https://science.slashdot.org/story/26/03/08/004240/a-first-for-humanity-confirmed-nasas-dart-mission-slowed-the-asteroids-orbit
- Source link: https://www.sciencenews.org/article/spacecraft-changed-asteroid-orbit-nasa
It was [3]2022's DART mission where NASA crashed a spacecraft into an asteroid — and the experiment "could have implications for protecting Earth from future asteroid strikes," [4]writes ScienceNews :
> A spacecraft slowed the orbit of a pair of asteroids around the sun by more than 10 micrometers per second... Within a month, researchers showed that the impact [5]shortened Dimorphos' 12-hour orbit by 32 minutes . Some of the [6]rocks knocked off of Dimorphos fled the vicinity completely , escaping the gravitational influence of the Dimorphos-Didymos pair, says planetary defense researcher Rahil Makadia of the University of Illinois Urbana-Champaign. Those rocky runaways took some momentum away from the duo and changed their joint motion around the sun.
>
> To figure out how much that motion was affected, astronomers watched the asteroids pass in front of distant stars, dimming some of the stars' light like a tiny eclipse. These blinks, called stellar occultations, can be visible from anywhere on Earth and are predictable in advance... Calculating how far off occultation timings were from predictions revealed that the asteroids' orbit around the sun was about 150 milliseconds slower than before the DART impact...
>
> Didymos and Dimorphos are not a threat to Earth, Makadia says, and weren't before DART. But knowing how a deliberate impact changes one asteroid's orbit can help make defense plans against another, "in case we need to do a kinetic impact for real."
The researchers spent nearly two and a half years to collect 22 measurements of the asteroid's post-crash position, relying on amateur astronomers "to go out into the middle of nowhere and observe the necessary stellar occultations," acvcording to their paper. Planetary defense researcher even tells ScienceNews "There was an observer who drove two days each way into the Australian outback to get these measurements."
[1] https://www.science.org/doi/10.1126/sciadv.aea4259
[2] https://www.nasa.gov/missions/dart/nasas-dart-mission-changed-orbit-of-asteroid-didymos-around-sun/
[3] https://science.slashdot.org/story/22/10/11/2052229/nasa-says-dart-mission-succeeded-in-shifting-asteroids-orbit
[4] https://www.sciencenews.org/article/spacecraft-changed-asteroid-orbit-nasa
[5] https://www.sciencenews.org/article/dart-mission-deflected-asteroid-for-planetary-defense
[6] https://www.sciencenews.org/article/nasa-dart-mission-boulder-asteroid-space
Leave it to the humans to bang rocks together (Score:1)
I remember being told more times than I can remember by more exceptionally credentialled people than I can count that nuking an asteroid wasn't going to do jack squat and a more subtle and controllable approach was called for in case an asteroid *needed* redirecting.
Well here we've got a split verdict at best. Yes momentum change did occur, but it was a messy and chaotic affair since this (like many if not most) was a rubble pile and the momentum exchange wasn't a clean pure inelastic or pure elastic collis
Re:Leave it to the humans to bang rocks together (Score:4, Interesting)
Yes, but... They used the craft itself. Your proposal of a nuke would give a strong, uniform push to the target. But to get it there would cost a LOT more. Nukes are heavy. Very heavy. If the target is legitimately threatening Earth, sure, throw all the money we have at it. For an experiment looking for data, this is fine.
Size of the effect (Score:4, Interesting)
10e-6 m/s works out to about one meter per day. Even after several years, that changes its position by one or two kilometers. That's not much in astronomical terms, and probably not enough to change some kind of Earth collision.
But before the Slashdot snark kicks in, keep in mind that this whole experiment was aimed principally at changing the orbit of the minimoon (Dimorphos) , rather than altering the orbit of the pair around the sun. That effect - the subject of this article - is a side effect of the main event. If they'd instead smashed into the main body (Didymos), the effect on the heliocentric velocity would be larger.
Re: (Score:2)
Nobody saw any of the sci-fi movies that dealt with this exact thing?
So... you slowed it a tiny, tiny, fraction of a millimeter (like taking a sheet of paper and slicing a sheet of paper down the broadside... a micrometer of a micron)... good job deflecting it! Are you gonna launch one of those asteroid-orbital knockers for everything that comes too close? Are you going to tie the launch to some sh**y AI? Do we have a thousand rockets ready to go exactly now to combat all the natural things heading for u
Re: (Score:2)
> All this proves is we can force an asteroid to divert a millimeter further away. What did this cost? What were the chances this would smack into us? Was it worth it?
Do you understand that one way how people find out whether a technique is effective is by trying them it out and seeing what happens?
Can you think of a scenario where having some real-world data on how a spacecraft alters the trajectory of a projectile might be useful?
Do you think remaining ignorant and inexperienced is an effective way to save money?
We can do it! (Score:2)
This implies that given the proper care, we should be able to put [1]2024 YR4 [slashdot.org] back on track to impact the Moon! [2]Humanity has really been half-assing this destroying the ecosystem [slashdot.org] and I feel like we can do better by annihilating with a well placed asteroid.
[1] https://science.slashdot.org/story/26/03/07/0028222/asteroid-2024-yr4-will-not-impact-the-moon
[2] https://news.slashdot.org/story/26/03/06/2210215/humanity-heating-planet-faster-than-ever-before-study-finds
How do you "slow an orbit"? (Score:2)
An appropriate headline for DevianArt perhaps, but here?
redunancy is solid engineering (Score:2)
while we don't really need the asteroid's help, it is nice to have a backup plan.