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NASA Space Science

NASA Is Going To Crash a Satellite Into an Asteroid (fortune.com) 89

The National Aeronautics and Space Administration (NASA) is moving ahead with plans to try out deflection techniques on a passing asteroid to prepare for future, threatening space matter. From a report: The space agency has entered the preliminary design phase for its Double Asteroid Redirection Test (DART). This represents the first trial of what's called the "kinetic impactor technique" of asteroid deflection. Put another way, NASA hopes that by hurling a refrigerator-sized spacecraft at one of the space rocks at a speed roughly nine times that of a bullet, it can knock the asteroid off course and save the Earth. The plan is to launch the first DART satellite at a binary asteroid called Didymos ("Twins"); the twin asteroids are scheduled to pass by earth in 2022 and 2024. (Neither pass poses any threat, according to NASA.) By striking one of the two asteroids, scientists will be able to measure the impact of the collision.
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NASA Is Going To Crash a Satellite Into an Asteroid

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  • by Jhon ( 241832 ) on Wednesday July 05, 2017 @02:04PM (#54748789) Homepage Journal

    ... said the Saurian physicist about 65 million years ago.

  • "What," said Trillian in a small quiet voice, "does asteriodcrash mean?"
    "It means," said Marvin, "that the probe is going to crash into the asteroid. Asteroid. . . . Crash. It's very simple to understand. What do you expect if you steal Hotblack Desiato's stuntprobe?

  • by Anonymous Coward

    or Unmanned?

  • Neither pass poses any threat, according to NASA.

    So what happens when the test works really well and suddenly that asteroid is knocked into a collision course with earth? What could possibly go wrong? While I would imagine the test isn't enough to cause a major trajectory change, this quote seems like the start of an end of the world movie.

    • I wish I could mod myself redundant...i deserve it for thinking I was going to have an original post.
    • "Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."

      At worst, they'll have a real use-case when they try the experiment again.

    • Good point. We should avoid preparing for the future so we can minimize the total number of experiments with potential to go wrong!
    • Well, if it works "really well" and that asteroid is knocked into a collision course with Earth, we could always do it again and knock it somewhere else.

      I'm pretty sure that NASA is smart enough to swat it "away" from Earth so that, at the very least, they'd have sufficient time to swat it away again.

    • So what happens when the test works really well and suddenly that asteroid is knocked into a collision course with earth?

      Nothing, because it won't happen. Any change of the asteroid's orbit that we're capable of effecting at this point in our technological evolution with non-nuclear means is barely measurable, and even the nuclear option would be negligible.

  • by Anonymous Coward

    I predict "an equal and opposite reaction"

  • by 140Mandak262Jamuna ( 970587 ) on Wednesday July 05, 2017 @02:18PM (#54748901) Journal

    The plan is to launch the first DART satellite at a binary asteroid called Didymos ("Twins"); the twin asteroids are scheduled to pass by earth in 2022 and 2024. (Neither pass poses any threat, according to NASA, as long as refrigerator sized hard metallic objects are not slamming into the agglomeration of rocks and ice held together with weak gravity ) By striking one of the two asteroids, scientists will be able to measure the impact of the collision and be the first one to hide under the desks, like school children in cold war era, if the deflected asteroids home in on us

    Fixed it for NASA.

    • by MightyYar ( 622222 ) on Wednesday July 05, 2017 @02:54PM (#54749221)

      Don't be worried about the one they hit - be worried about it's angry, defensive twin.

    • by rtb61 ( 674572 )

      The nature of the asteroid is just another thing to be taken into account. Dense heavy and you are really battling inertia and of course light easy to penetrate means you might pass through but you will still transfer energy into it (if you understand the compression and resistance to penetration and how it distributes to the rest of the mass, you will understand quite a lot is transferred.

      The advantage of a purely kinetic versus nuclear, is that if you fuck it up, you will still get hit but at least you w

  • by Anonymous Coward

    Isn't this a fairly straightforward calculation? And given the exact details of this asteroid's spin and other variables aren't the results going to be fairly accurate for just this one asteroid and maybe not extrapolatable to others? I ain't no English jeanus, either.

    • by Phil Karn ( 14620 ) <`karn' `at' `ka9q.net'> on Wednesday July 05, 2017 @05:38PM (#54750825) Homepage

      Actually no, it's not a straightforward calculation. That's why they want to conduct the test.

      It's not a simple collision like we learned about in physics class, with the change in the asteroid's momentum coming entirely from the impactor. The impactor will hit at extremely high velocity (by earth standards), meaning that it will carry a lot of kinetic energy (one half mass times velocity squared) in a small volume. This kinetic energy will vaporize and blow off part of the asteroid, which because of the asteroid's small size, will completely escape.

      The mass of the ejecta will greatly exceed the mass of the impactor, so even though it may move much more slowly than the impactor it will carry away considerably more momentum (mass times velocity). The momentum of this ejecta will have most of the effect on the asteroid's trajectory.

      But it's unknown exactly how much momentum will be carried away by the ejecta as this depends on the makeup of the asteroid, its density, porosity, how quickly the impactor stops and releases its energy, etc. So that's why they want to try it.

      A similar effect was at play in the JFK assassination that helped cause the counter-intuitive "back and to the right" motion of his head that had so many people incorrectly thinking there was a second shooter.

      • The mass of the ejecta will greatly exceed the mass of the impactor, so even though it may move much more slowly than the impactor it will carry away considerably more momentum (mass times velocity).

        It will only "carry away the momentum" if you hit it against the direction of its motion. Depending on the hit point, you can nudge it in practically any direction (although some are more favourable from the POV of celestial mechanics and our technological limitations).

        But it's unknown exactly how much momentum will be carried away by the ejecta as this depends on the makeup of the asteroid, its density, porosity, how quickly the impactor stops and releases its energy, etc.

        But you ought to be at least able to consider a perfectly inelastic collision as the minimum for your momentum transfer. Seems like everything else is an (uncertain) bonus.

  • According to NASA "Neither pass poses any threat" - question is will they poses a threat after we hit them with DART? Or will we learn in 2151 that NASA's experiment from 2022 had a cascading effect and one of the Didymos/twins is going to hit earth.
    • by gtall ( 79522 )

      Yeah, yer right. We shouldn't attempt deflection experiments on asteroids because they might go wrong. We should wait until one has our address stamped on its ass and then either be too late to deflect it or have one Hail Mary shot at it.

  • Not on accident?

  • People who don't understand that a refrigerator sized satellite won't blow apart or make large changes to the orbit of a 527 billion kg asteroid [johnstonsarchive.net].

    • by Shotgun ( 30919 )

      I'm wondering what happens when the fridge hits at 6 time the speed of a bullet. (WTF is that? Why can't they just give a velocity?)
      Will it vaporize? Punch through?

      I'd like to see them harness another, much smaller asteroid, by landing thrusters on it. Then, using it's much larger mass, impact with much lower velocity. Slowly change the orbit of the conglomerate to bring it all into a near Earth orbit and then use it as the beginning of a space station.

    • by e r ( 2847683 )
      They're planning on impacting the moon of Didymos-- nicknamed Didymoon-- not Didymos itself.
      At present the mass of Didymoon is unknown [phys.org], but certainly smaller than 527 billion kg.
    • If we can change its velocity by 1 cm/s, after 1 year, its position will have changed by almost 316 K. That may not sound like much, but it would probably be enough to change a grazing impact to a very near miss. And, of course, the faster the projectile, the higher the kinetic energy is and the more effective it is. And if we can't get a higher impact velocity, we can always make the projectile more massive; this won't raise the kinetic energy much, but it will improve the momentum which might be enough
  • NASA Is Going To Crash a Satellite Into an Asteroid on Purpose

    I mean, accidental hypersonic impacts into things is kind of old hat. ;)

  • FTA: "Neither pass poses any threat, according to NASA." It would be hilarious if that collision will suddenly change the asteroid's path to collide with Earth.
  • Are they the least bit worried that they put an asteroid on an eventual collision course?
    • by gtall ( 79522 )

      NASA Scientist: Let's deflect an asteroid.

      NASA Supervisor: But what if we deflect it into the Earth, we'd better run some simulations with our supercomputers first.

      NASA Scientist: Bah, humbug. Let's just wing it.

  • Dear NASA,

    If you ever wish to remain relevant, you had best put someone (a human), on a celestial body, and quick. The Moon is always an option, as is Mars, Venus, etc. But at the current rate things are going, people are focusing a bit too much on...earthly affairs. They are forgetting that there are other worlds out there, and that they are accessible to us; hence, they begin to care too much about what they have here, in front of them. And as such, they are beginning to feel claustrophobic, even when the

  • Am I the only one that was reminded of the satellite crashing into the mother ship at the beginning of Independence Day?
  • But its common knowledge that these asteroids are being sent by the Arachnids.
    You know its true, we gotta send our soldiers to Klendathu



    "We thought we were smarter than the Bugs" [imdb.com]
  • They already did this with a comet. https://www.jpl.nasa.gov/missions/deep-impact/

  • Needed: 1 drilling team willing to crash their spacecraft craft into an asteroid, drill a hole in it, place a nuclear weapon and then kiss their asses goodbye. Send CV and client testimonials to NASA, c/o CraZY Eddie, PO Box 1998, Canaveral, FL

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