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NASA is preparing to test an asteroid defense system

By Shawn Knight · 27 replies
Jan 30, 2019
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  1. It’s why scientists at NASA are planning to launch the Double Asteroid Redirection Test (DART), a space probe expected to launch in 2020 with the goal of slamming into an asteroid. The hope is that the impact will be able to alter the asteroid’s orbit.

    Given the vast expanse of space, even a tiny alteration in an asteroid’s projected path could be enough to cause it to miss Earth and potentially save humanity over the course of millions of miles.

    NASA’s target with DART is Didymos, a binary asteroid system orbited by a smaller satellite roughly 490 feet in diameter. The probe will crash into this smaller asteroid. Neither are on a path for Earth and there’s no possibility of an impact causing danger to us.

    Mark Fittock, a Monash University alum that worked on NASA’s InSight lander, told The Sydney Morning Herald that if they’re smart about what they hit the asteroid with, they could use something smaller but to better effect.

    “If this was really happening and we had to stop it, we don’t know much about our options at the moment – we know we could hit something, but we don’t know what to hit it with,” he said.

    Lead image courtesy Mopic via Shutterstock

    Permalink to story.

  2. TomSEA

    TomSEA TechSpot Chancellor Posts: 3,129   +1,635

    Interesting. I remember reading an article a while back where NASA wanted to avoid hitting asteroids because it would create a debris field that could potentially be worse than the single asteroid itself.

    In that article, they stated their best option was to put a satellite in orbit around the asteroid - like this one - but use the orbit gravity influences to push or pull the asteroid to a different path.

    Looks like they've changed their minds.
    Uncle Al likes this.
  3. Lew Zealand

    Lew Zealand TS Guru Posts: 775   +660

    When you're looking for funding from Congress, big booms are much more impressive than a boring gravity tugboat.
    JaredTheDragon likes this.
  4. Uncle Al

    Uncle Al TS Evangelist Posts: 5,541   +3,919

    I have also read that by the time the asteriod is detected, a rocket launched to reach it, etc. it would be so close that success isn't a reality. Maybe we need to launch a couple of really large pool table bumpers ......
  5. amstech

    amstech IT Overlord Posts: 2,286   +1,498

    "I'm leavin on a jet plane, don't know when I'll be back again"
  6. wiyosaya

    wiyosaya TS Evangelist Posts: 4,131   +2,420

    To me, it sounds like they are investigating what will happen. Asteroid composition can vary greatly, and what is good for one type might not work with another.
    Contribute computing power to detecting possible Earth-threatening asteroids. https://asteroidsathome.net/boinc/ :D
  7. ShagnWagn

    ShagnWagn TS Guru Posts: 773   +605

    "NASA’s target with DART is Didymos, a binary asteroid system orbited by a smaller satellite roughly 490 feet in diameter. The probe will crash into this smaller asteroid."

    Let's pretend there is civilization on planet in another solar system and we bump this asteroid into their path? ;)
    JamesSWD likes this.
  8. JaredTheDragon

    JaredTheDragon TS Guru Posts: 623   +400

    So we also have to pretend the sun isn't here, the asteroid isn't orbiting its buddy, Jupiter and the Jovians don't exist, and gravity and charge aren't real. Then we have to also pretend we can hit this small asteroid with enough energy to push it to the speed of light, or close enough for this baby 'roid to scoot off to a nearby star with a planet, only to arrive there some 4-8 years later (at light speed) to find that the nearby star or planet isn't even there anymore since it's also orbiting around the galactic core. That's Relativity, you know. You can't just fly TO a distant object while it's in motion. You can't even fly to the moon like that, or achieve orbit with a simple velocity.

    Anyway that was fun, cool story bro.
    Tanstar likes this.
  9. Xclusiveitalian

    Xclusiveitalian TS Evangelist Posts: 788   +173

    Can't we just attach a nuke and smack it into these things to push them?
  10. VitalyT

    VitalyT Russ-Puss Posts: 4,540   +3,133

    Reminds me of Charlie Brown of the missile defence...

    And as for...
    I would chill on my couch, with beer and popcorn, watching Armageddon.
    Last edited: Jan 31, 2019
  11. Reachable

    Reachable TS Evangelist Posts: 369   +183

    That's what they say. In a real scenario just the impact of a probe would likely not be sufficient.

    I imagine NASA would have encountered a bit of resistance if they'd wanted to use a nuke for their upcoming test.
  12. JaredTheDragon

    JaredTheDragon TS Guru Posts: 623   +400

    Nukes aren't real, silly. It's 2019, time to just let go of our childhoods.

    Considering this is the most lethal global threat we could face, I applaud them for trying anything at all. But we don't need shoddy fiction to counter incoming doom, just real physics.
  13. lipe123

    lipe123 TS Evangelist Posts: 807   +349

    I was expecting some fancy laser beam heating up one side or something...

    What mental prowess "we'll crash something into the side of it" really?! What if its a really large asteroid that weighs 100 metric tons? We'll build a 50 ton ship to crash into it?

    Seems kinda meh.
  14. ShagnWagn

    ShagnWagn TS Guru Posts: 773   +605

    You must be fun at parties.
    JamesSWD likes this.
  15. wiyosaya

    wiyosaya TS Evangelist Posts: 4,131   +2,420

    In the physics of it, it is not the mass that counts. It is the velocity at which the mass travels.

    I'm putting on my nerd hat now. *nerd* :laughing:

    The equation is:

    KE = (1/2)MV^2

    Where KE = kinetic energy, M = mass and V = velocity - so

    Kinetic Energy = (1/2) x Mass x Velocity squared. Say you get a probe traveling 50,000 km/hr which is not unusual for a space probe. That's 50,000,000 Meters per hour and almost 14,000 meters per second. Say the probe is 50kg. So:

    KE = (1/2) x 50kg x (14,000m/s)^2

    = 25kg x 196,000,000 m^2/s^2
    = 4,900,000,000 kg x m^2/s^2
    = 4,900 Billion joules or 4.9 Giga Joules, and since the probe is traveling at a continuous velocity, this equates to 4.9 Giga Watts.

    No small amount of energy, there. While that it still only a fraction of a megaton of TNT, that amount could be enough to nudge the smaller asteroid in another direction, and since the two asteroids are gravity locked, the smaller asteroid should tug the larger one along with it. I highly suspect that this particular asteroid pair was chosen for that reason since it approximates a solution that has been previously theorized.

    It has been proposed that if discovered soon enough, a small nudge like this would be a sufficient course alteration to prevent an asteroid from hitting Earth. Or, placing a craft in orbit around an asteroid might be enough to tug an asteroid's orbital path enough so that it misses earth. These are much preferable solutions to splitting an asteroid up into many smaller pieces which may end up causing more and wide-spread destruction.

    I suspect that this is the first serious step toward investigating what might need to be done in the real world to sufficiently counter such a threat. IMO, a test like this is a good start. Good science does not necessarily make an immediate try for the ultimate solution.

    Of course, more testing will be needed, and no one knows whether a solution will be found by the time it is really needed. Its a start, though, and better than putting our heads between our legs and kissing our collective a$$es goodbye without even trying to find a solution - at least IMO.
  16. wiyosaya

    wiyosaya TS Evangelist Posts: 4,131   +2,420

    More like non-relativistic celestial mechanics.
  17. havok585

    havok585 TS Addict Posts: 205   +61

    NASA is preparing another fairy tail, coming soon on the big screen, yay.
    JaredTheDragon likes this.
  18. mbrowne5061

    mbrowne5061 TS Evangelist Posts: 1,240   +693

    The key is they don't want to hit something too close. If you see it years in advance, it likely doesn't matter if you shatter the rock upon impact. All the different pieces will get scattered onto trajectories that will almost certainly miss Earth. If one piece, by chance, happens to still be on a collision course after fracturing, it will be smaller, and likely slower moving too - we just hit it again, and again, until either all the pieces are on harmless trajectories or are too small/slow to pose a risk to the planet.

    It is this model of asteroid defense NASA is testing, as it is cheap and relatively simple and low tech (over say, painting the asteroid with a liquid solar sail).

    Now, if we have months or weeks notice, yeah, they probably are not going to want that thing to break up. But if we have that little time, we likely don't have enough time to do anything at all about it. Maybe they'll still impact it and risk a fracturing anyway. Smaller rocks may only wipe out sections of a country or continent, instead of the entire planet.
  19. JamesSWD

    JamesSWD TS Maniac Posts: 331   +182

    > Humans bump an asteroid off its collision course with Earth
    > Travels through space on its new path for millions of years
    > Slams into planet, causing extinction of dinosaurs, giving rise to humans
    > Cue Twilight Zone theme
  20. JaredTheDragon

    JaredTheDragon TS Guru Posts: 623   +400

    Using a laser would be no different than using any other form of mass. Photons just have considerably less than larger, baryonic matter.

    That said, even the Space Shuttle could only haul up 30 tons of cargo max. Hubble itself was only just over 12 tons. So you're correct, getting 50 tons of matter up there WITH enough fuel to accelerate to an asteroid is pretty much maxing out current tech. I mean they CAN do it in phases, but it's probably just going to miss anyway.
  21. JaredTheDragon

    JaredTheDragon TS Guru Posts: 623   +400

    Imagine living in a Universe where you say that mass doesn't count, then follow it up with an equation explicitly based on mass.

    Imagine not knowing how orbital dynamics work at all, and not knowing that everything orbiting the sun is actually orbiting the sun. We already went over this and demolished it, buddy.

    Imagine not knowing what "relative" means.

    I'm an absolute blast, thanks for noticing. ;)
  22. dogofwars

    dogofwars TS Addict Posts: 197   +76

    But he is right about that. For instance Voyager 1 or 2 can't recall is about several hundreds miles off so just imagine another solar system that would be impossible.
  23. Aux101

    Aux101 TS Enthusiast Posts: 47   +6

    Detonating a nuke at close range, the shock wave would push on 'the rock' without creating debris.
  24. ShagnWagn

    ShagnWagn TS Guru Posts: 773   +605

    Right about what?

    I wasn't reference we intentionally targeting another solar system, but that inadvertently we pushed its path eventually into some other planet. It's a joke. Kind of like a pinball effect... I guess the wink of a joke wasn't enough for him? Then per say that civilization pushes it and hundreds of years later it gets to the next civilization. ;)

    I figure JaredTheTroll will come back and troll some more.
  25. cliffordcooley

    cliffordcooley TS Guardian Fighter Posts: 11,516   +5,080

    What are we shooting at the moon?

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