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How To Deflect an Asteroid With Today's Technology

Soulskill posted about 4 years ago | from the don't-use-the-phasers dept.

NASA 264

Matt_dk writes "Apollo 9 astronaut Rusty Schweickart is among an international group of people championing the need for the human race to prepare for what will certainly happen one day: an asteroid threat to Earth. Schweickart said the technology is available today to send a mission to an asteroid in an attempt to move it, or change its orbit so that an asteroid that threatens to hit Earth will pass by harmlessly. But what would such a mission entail?"

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Let's get this over with. (5, Funny)

Anonymous Coward | about 4 years ago | (#33909708)

Bruce Willis.

Re:Let's get this over with. (0)

pilgrim23 (716938) | about 4 years ago | (#33909724)

I always thought deflection was inversely related to the amount of Kryptonite the asteroid contains.

Re:Let's get this over with. (0)

GarretSidzaka (1417217) | about 4 years ago | (#33909730)

damn you beat me to posting bruce willis, but you are right, thats all they need

I disagree. Not Bruce Willis.... (0)

Anonymous Coward | about 4 years ago | (#33909774)

We'll just send Chuck Norris up there to roundhouse-kick it out of the way.

Spoiler alert (5, Funny)

srussia (884021) | about 4 years ago | (#33909870)

Bruce Willis died deflecting the last one. It'll have to be Ben Affleck next time... finally.

Re:Spoiler alert (0)

Anonymous Coward | about 4 years ago | (#33910142)

Can we send Leonardo DiCaprio with him so he'll get blown up as well?

Re:Spoiler alert (1)

Mongoose Disciple (722373) | about 4 years ago | (#33910298)

Can we send Leonardo DiCaprio with him so he'll get blown up as well?

I don't know, Titanic aside he's been in some pretty good movies.

The Departed, Inception, etc.

Hell, I even sat through Catch Me If You Can three or four times in the theatre as date movies and that wasn't that bad either. Ah, to be young and non-monogamous again.

Re:Spoiler alert (1)

cparker15 (779546) | about 4 years ago | (#33910406)

You liked Titanic and you know it.

If you miss being non-monogamous so much, you should've stayed that way... I don't think it's far-fetched to expect the Slashdot crowd to grok alternative lifestyle choices.

Re:Spoiler alert (2, Insightful)

Mongoose Disciple (722373) | about 4 years ago | (#33910612)

If you miss being non-monogamous so much, you should've stayed that way...

I miss the young more than the non-monogamous, and I didn't get a choice on that.

It's true that I do miss parts of being single at times or are nostalgic for its bright spots, but it's also true that I do overall prefer the life I've chosen to replace it with. My wife is amazing. Family life with anyone else I'd met or dated never seemed like a good idea, but this is right for me.

It all depends on detection... (5, Insightful)

Covalent (1001277) | about 4 years ago | (#33909766)

Obviously it depends on detection time. If we detect the asteroid years ahead of time, then even tiny changes in course will save us from impact. This could be done by simply crashing a small probe into it...something we've done successfully on more than one occasion. But, if we don't detect it until it's nearly on top of us then it may well be beyond our ability to do it. Therefore, the obvious solution is to increase detection technology.

Re:It all depends on detection... (1)

SudoGhost (1779150) | about 4 years ago | (#33909852)

You can't make a movie out of that, that's boring! Boring doesn't make the news, scary does!

Re:It all depends on detection... (5, Interesting)

WindBourne (631190) | about 4 years ago | (#33909878)

Oddly, we are doing detection totally wrong. We have several scopes out there looking for asteroids. But they will be picking up monster ones. The ones that are far more likely to hit us will not be picked up as easily. So what is needed? A cheap cheap telescope that can be roof mounted, and uses POE to provide data/power. In doing that, it will encourage a number of geeks around the world to install these. Then the scope relays data back to a central server where pics are compared. In particular, if one gets a flash, not a big deal. OTH, if several spread around the world get a flash in the same area (basically sunlight glancing off an asteroid as it slowly turns), then it says that the area should be looked at. This approach will enable us to know WHERE to look for small to medium asteroids.

Re:It all depends on detection... (2, Insightful)

Covalent (1001277) | about 4 years ago | (#33909972)

I couldn't agree more. A big asteroid impact would also likely be out of our hands in terms of prevention...but a small impact could still devastate a city, and we could actually deflect it. This has "distributed computing project" written all over it.

Re:It all depends on detection... (0, Troll)

blair1q (305137) | about 4 years ago | (#33910500)

You're going to deflect an asteroid with distributed computing exactly how?

Re:It all depends on detection... (3, Interesting)

Hylandr (813770) | about 4 years ago | (#33910582)

I would buy one of these in a heartbeat, and SETI already has the software and server resources to start to handle this. The expensive part though, will be the mechanisms for positioning, and reliably tracking in the night sky. Good tracking isn't cheap, as even the slightest vibrations will obfuscate really small objects. Add to that vibrations inherent on the roof of a home, Doors, washing machines, children playing, loud cars, wind etc. You would need a small solid tower separate from the home, as well as a lightning rod etc.

- Dan.

Re:It all depends on detection... (2, Insightful)

denis-The-menace (471988) | about 4 years ago | (#33910006)

It needs to be off-planet to see better.
Place it on the moon, in one of the 2 LaGrange points, in orbit, or where ever it makes $en$e.

Because right now we have next to nothing and this currently popular "manage by crisis" management style will do nothing to help.

Re:It all depends on detection... (4, Interesting)

purfledspruce (821548) | about 4 years ago | (#33910296)

The moon would be ok. In a Venus-trailing orbit would be much better. One of the problems we have is that we can only see asteroids when they're lit up by the Sun, and asteroids that have an orbit almost entirely inside of the Earth's orbit are hard to see--only the backside gets lit up, so we can't see them very well.

A vehicle placed at Venus's orbit, though, would be able to see those potentially dangerous asteroids quite well.

Re:It all depends on detection... (1)

CrimsonAvenger (580665) | about 4 years ago | (#33910594)

in one of the 2 LaGrange points,

The TWO Lagrange points? There are five last I checked.

Re:It all depends on detection... (0)

Anonymous Coward | about 4 years ago | (#33910690)

The TWO Lagrange points? There are five last I checked.

Don't be an ass...

L3 isn't very stable. Read:Fuel

L4 and L5 are too broad. There's little potential energy difference from point to point. It's hard to stay in a single spot. Read:Fuel

So yes, practically speaking, Earth has TWO useful Lagrange points. Last time I checked.

Have Mercy... (0)

Anonymous Coward | about 4 years ago | (#33910702)

The TWO Lagrange points? There are five last I checked.

Make that six, you forgot about one down in Texas, ya know, that's got a shack just outside?

Re:It all depends on detection... (2, Interesting)

hcdejong (561314) | about 4 years ago | (#33910358)

Do we have evidence that small asteroids can be detected this way? Does a small asteroid's albedo ever get high enough to be picked up by a small telescope?

Re:It all depends on detection... (2, Informative)

jmichaelg (148257) | about 4 years ago | (#33910514)

Depends on what you call small.

There's a mailing list, Minor Planet Mailing List [yahoo.com] , where amateur and professional asteroid hunters congregate and their equipment covers the gamut from 8" up meters wide scopes.

Regardless of scope size, they are all limited by the fact that it's hard to look towards the sun to spot asteroids whose orbits are primarily sunward of us. A well shaded scope parked at a Lagrange point could go a long ways towards addressing that threat.

Re:It all depends on detection... (1)

WindBourne (631190) | about 4 years ago | (#33910580)

The vast majority of asteroids, and some moons, were discovered in this very fashion. While a number of planets were located via calculations, it is flashes of light from a surface that found the asteroids.
Keep in mind that c-type asteroids have an average albedo of 0.03. Basically, pretty damn dark. But there will be points on these that are not. They will be seen as flashes of lights, which are normally ignored. However, if you have a dozen scopes looking in the same area of sky and are very remote from each other, then it is likely something of interest.

Re:It all depends on detection... (4, Interesting)

blair1q (305137) | about 4 years ago | (#33910478)

We don't only find the monster ones.

We commonly track asteroids under 500 feet wide [msn.com] ; much smaller than a planet-killer.

It will be comparatively easy to detect a planet-killer sized asteroid and determine its trajectory in plenty of time to launch a deterrent mission.

A surprise impact by anything with major destructive capability is vanishingly unlikely at this point. Improvements in detection shouldn't be prioritized, but should be allowed to continue at a normal pace.

Deciding how to minimize the destruction should be the focus, and we don't really know how to do it with a high degree of confidence, yet. So deflection technology should be prioritized.

Re:It all depends on detection... (1)

cindyann (1916572) | about 4 years ago | (#33910740)

It will be comparatively easy to detect a planet-killer sized asteroid and determine its trajectory in plenty of time to launch a deterrent mission.

So we deflect it a teeny bit this time--- Enough to miss us this time around, but what if gravity pulls it back and one of the next times around we're in its path -- again.

Wouldn't we want to deflect it a lot, e.g. send it out of the plane of the ecliptic, maybe due galactic North? Or South?

At least then when it comes back, as it ultimately will, the odds of Earth being in its path are vanishingly small? Or at least small for a really long time?

OTOH I can't see most people being too happy if we send Halley's comet on 5000 year detour. Then again, it's last visit was so underwhelming maybe nobody would really care.

Re:It all depends on detection... (0)

Anonymous Coward | about 4 years ago | (#33910106)

Obviously it depends on detection time. If we detect the asteroid years ahead of time, then even tiny changes in course will save us from impact. This could be done by simply crashing a small probe into it...something we've done successfully on more than one occasion. But, if we don't detect it until it's nearly on top of us then it may well be beyond our ability to do it.

Therefore, the obvious solution is to increase detection technology.

A non-destructive way of changing it course could be flying a craft close to the side of the asteroid you would like the asteroid to deflect to. The small amount of gravity that a space ship would impart on the asteroid can "pull" it off of its trajectory. As mentioned, it would require plenty of detection.

Re:It all depends on detection... (2, Interesting)

blair1q (305137) | about 4 years ago | (#33910560)

You couldn't do it by station-keeping next to the asteroid. You'd have to maintain thrust directed at the asteroid. First, the thrust couldn't last very long, and second, it would just push the asteroid back away from the ship. You could fire it in a conical pattern, but then you decrease the effective thrust you get from your fuel.

All you really do by putting a lightweight object near an asteroid is create a heavier asteroid. If you have enough reaction mass to manage the sort of station-keeping you imagine, then you might as well put the vehicle on the asteroid and point the thrust outward, and push the asteroid into another trajectory.

Re:It all depends on detection... (1)

JWSmythe (446288) | about 4 years ago | (#33910144)

    I don't know why the solution is always to blow it up or crash something into it. We have a wonderful history of knowledge about how objects have avoided hitting the earth. A few giant planets in orbit farther from our sun than we are, and a moon. You don't crash things into the moving object. You let the moving object crash into your defenses.

    For example, if someone is shooting at you, do you shoot at their bullet? No, you hide behind cover, or carry it with you.

    Most of the objects we've detected are pretty small (relative to the earth). A large high orbit object (like the moon) is a pretty damned good defense. Now, if we could control this like a shield, if another object were to come towards the earth, it could be deflected (bounced away from impact) or disrupted (i.e., break it into a bunch of smaller pieces).

    Launching an artificial object isn't exactly practical, but we've already done a good bit of it. I wonder what the total mass of the current LEO objects is.

    An accumulation of matter isn't ideal. But think of driving off the road. If you run into a brick wall or a snowbank, you're probably going to stop, be deflected, or disrupted.

    So the solution isn't the bigger space weapon. It is the better space shield.

Re:It all depends on detection... (1)

Nos. (179609) | about 4 years ago | (#33910274)

Let me get this straight...
Instead of launching a relatively small probe/bomb/whatever to hit the object as far away as possible making a tiny change to its trajectory, your solution is to build another moon or moon like object and swing it around like a shield?

Re:It all depends on detection... (1)

JWSmythe (446288) | about 4 years ago | (#33910554)

    Well, we've only had a 50% success rate hitting Mars, so ya, I think a shield in closer proximity to earth would be a lot more manageable.

    But, if you read the article, it's actually clear.

"In a way, the kinetic impact was demonstrated by the Deep Impact mission back in 2005," said Schweickart. "But that was a very big target and a small impactor that had relatively no effect on the comet. So, we haven't really demonstrated the capability to have the guidance necessary to deflect a moderately sized asteroid."

    In simpler words, we couldn't change the trajectory of a moderately sized asteroid with a 815 pound cannon ball. The change has to be pretty significant and pretty far out. If other factors are guiding the object (which they would be), gravity from the sun and other planets can and will effect it's flightpath. If you knock it 1 degree, it may be pulled straight back onto it's original course. And lets not forget the Earth seems to have a bit of gravity (something like 1g on the ellipsoid, on a standard day, with standard pressure), so bumping the object off from a direct path to earth may just result in it still coming straight in.

    Here's a test for you... Have a friend drop a 16 pound bowling ball from a 10 story building straight down at your head. When it reaches 9 stories up, shoot it with a BB gun, and hope that deflects it.

    Nope, I'd rather have a roof for it to hit.

Re:It all depends on detection... (2, Informative)

TheTrueScotsman (1191887) | about 4 years ago | (#33910640)

kinetic energy = 0.5 * mass * (velocity ^ 2). At the differential velocity of an asteroid, you'll need one heck of a lot of mass in your shield. Far better to move it small amounts over a long time period (i.e. early detection).

Re:It all depends on detection... (0)

Anonymous Coward | about 4 years ago | (#33910164)

This is exactly what was said before we had the Zombie Apocalypse and nobody listened! DETECTION!

Where is the private sector here? (1, Troll)

140Mandak262Jamuna (970587) | about 4 years ago | (#33910172)

Everyone knows Government only sucks your income through taxation and wastes it. It can not be a solution to anything. They can't even see a banking crisis coming, how are they going to see an asteroid coming? This is the typical muddled liberal thinking that envisages a single provider socialistic detection system.

The Tennessee Fire Brigade has shown the right way. A subscription based detection system. Only the Asteroids that are going to hit the subscriber's home will be detected. If you don't pay the 75$ a year subscription fee, sorry buddy. An asteroid is going to hit your home and we will watch it with glee.

Re:Where is the private sector here? (2, Insightful)

0123456 (636235) | about 4 years ago | (#33910472)

Cost of preventing impact >>> (cost of impact * probabilitiy of impact)

About once a century we get an impact that's equivalent to a few megatons, and there's a 75% chance of it hitting an ocean and about a 99% chance of not hitting a heavily populated area. Sucks if your farm happens to be ground zero, but there's no sane reason to spend billions of dollars a year trying to prevent it.

Re:Where is the private sector here? (1)

cindyann (1916572) | about 4 years ago | (#33910650)

They can't even see a banking crisis coming....

It's usually easier to see it coming if you don't close your eyes to it.

Re:It all depends on detection... (1)

QuantumG (50515) | about 4 years ago | (#33910198)

I don't know why people keep saying this. LLNL were tasked with determining whether or not a big close asteroid could be diverted using nuclear weapons - that is, find out what the last resort is..

http://www.youtube.com/watch?v=1eOJ9doYtN0 [youtube.com]

They found that indeed, the use of nuclear weapons could deflect or even destroy an incoming asteroid. Yes, long term deflection using less extreme methods are much more preferable, but should it be necessary to take out an asteroid that is detected so late that it is already on terminal approach, the PHDs who work on modelling nuclear explosions say it can be done.

So please, stop doomsaying, the experts say they are ready to nuke the sucker if that's what needs to be done.

Re:It all depends on detection... (3, Interesting)

0123456 (636235) | about 4 years ago | (#33910642)

So please, stop doomsaying, the experts say they are ready to nuke the sucker if that's what needs to be done.

MIT were saying that back in the 60s, so it's not really news.

But there's the slight problem of being able to _get_ a nuke to the asteroid in the first place; the MIT study used an Apollo CSM on top of a Saturn V with a 100MT nuke on board, and there's not much hope of being able to fix up one of the remaining Saturn Vs to fly at short notice and nuke an incoming asteroid today (they also planned to launch 5-6 of them to allow for failures and near misses).

Re:It all depends on detection... (1)

SnarfQuest (469614) | about 4 years ago | (#33910268)

then even tiny changes in course will save us from impact

Remember that atreroid we deflected a couple years ago, well there was apparently a slight miscalculation, and it WOULD HAVE missed if we hadn't "deflected" it.

Re:It all depends on detection... (2, Interesting)

tbischel (862773) | about 4 years ago | (#33910444)

one way to change an asteroid's trajectory over a long period of time is to take advantage of the Yarkovsky effect [space.com] .

Re:It all depends on detection... (1)

0123456 (636235) | about 4 years ago | (#33910562)

Obviously it depends on detection time. If we detect the asteroid years ahead of time, then even tiny changes in course will save us from impact.

If you detect it years ahead of time, can you actually measure the orbit accurately enough to prove that it's going to hit, when a small error in orbital measurements could make the difference between impact and missing?

If you had a tiny error in the orbital measurement which just happened to match the tiny course change you applied a few years before impact, then you could take an asteroid which wasn't going to hit the Earth and _cause_ an impact.

put it in a wormhole and have it jump over earth! (1)

Joe The Dragon (967727) | about 4 years ago | (#33909806)

put it in a wormhole and have it jump over earth!

Beck and Limbaugh (0)

Anonymous Coward | about 4 years ago | (#33909848)

That's all you need.

Re:Beck and Limbaugh (1, Funny)

adamstew (909658) | about 4 years ago | (#33910184)

I see where you're going: Load up Rush Limbaugh in to Glen Beck's huge mouth. The pressure from all the hot air being unable to escape will build up. Very quickly that hot air will blast Rush Limbaugh in to space to impact the asteroid. This collision will be enough to deflect the asteroid back out towards space.

tough choice (2, Interesting)

djdanlib (732853) | about 4 years ago | (#33909860)

What if we only have the ability to divert it a little bit, if and when that comes? Then we only control WHERE it hits, not WHETHER it hits. So how do we choose, I wonder?

Re:tough choice (-1, Flamebait)

vekrander (1400525) | about 4 years ago | (#33909912)

The middle east, if possible, obviously.

Re:tough choice (2, Informative)

Ephemeriis (315124) | about 4 years ago | (#33909986)

What if we only have the ability to divert it a little bit, if and when that comes? Then we only control WHERE it hits, not WHETHER it hits. So how do we choose, I wonder?

If the asteroid is big enough, it won't really matter where it hits. Anywhere on the planet will be a global disaster.

Re:tough choice (2, Informative)

smooth wombat (796938) | about 4 years ago | (#33910220)

At least get the quote right:

Those Asteroids that hit this morning---those were nothing---the size of basketballs and Volkswagens. This new one we're tracking is the size of Texas, Mr. President. It's what we call a Global Killer....the end of mankind. Half the world will be incinerated by the heat blast.....the rest will freeze to death in a nuclear winter. Basically, the worst part of the Bible !

Re:tough choice (1)

sznupi (719324) | about 4 years ago | (#33910496)

Though most should be small enough that it will make a difference. Oh well, I'm sure what's good for space-faring countries will have to be good for humanity (of course it will get really funny if 2+ of them disagree)

And this mess is pretty much inevitable - in the initial stages of deflection, a risk for some places will rise while it gets smaller for some other (luckily: the uncertainties involved should be big enough so that it won't be clear which are which)

Re:tough choice (-1, Flamebait)

Anonymous Coward | about 4 years ago | (#33910170)

I say we make it hit Washington DC

Re:tough choice (1)

SnarfQuest (469614) | about 4 years ago | (#33910330)

According to most of the movies I've seen, any diversions will cause it to hit either Tokyo or Los Angeles. I don't live at either location, so it's all fine with me.

Re:tough choice (1)

pckl300 (1525891) | about 4 years ago | (#33910654)

Can we not nuke it into not-so-disastrous pieces?

Early Detection (2, Interesting)

vekrander (1400525) | about 4 years ago | (#33909864)

The most beneficial thing we could do is build a system to detect such asteroids as early as possible. Once located, it's easy to deflect an asteroid that's far away. A small nudge or impact from a probe or the like would push it out of an intercept course while it's still far away. The closer it gets, the more force is required to push it off at an angle that will keep it out of our way. It may take a few newtons of force to deflect an astroid coming in from as far away as saturn, but much more to deflect an asteroid that's already close to mars.

I guess in simpler terms, if we had a really awesome early detection system, all we need is a small rocket launched from the ISS to impact it, wheras with a crappy system, we need Bruce Willis.

Re:Early Detection (1)

Wonko the Sane (25252) | about 4 years ago | (#33909896)

A small nudge or impact from a probe or the like would push it out of an intercept course while it's still far away.

It would be more fun to just blow it up.

Re:Early Detection (1)

Hotawa Hawk-eye (976755) | about 4 years ago | (#33910282)

So instead of getting hit by a bullet, Earth would get hit by buckshot. While that _might_ be better (if the fragments are all or mostly small enough that they don't survive the trip through the atmosphere) it could also be much, much worse.

Think of deflection as playing interplanetary billiards (deflect one asteroid by just a little bit and have it strike another one such that both get out of our way, or deflect it so that instead of hitting Earth it hits Mars or Venus.) Actually, what would be really cool would be if we could deflect it and slow it enough to capture it -- if it's made of the right material, it could sweep up some of the space junk that's already up there, and we could mine it for resources we could use in space that otherwise would be too expensive to ship from Earth into orbit.

Re:Early Detection (1)

universalconstant (1269920) | about 4 years ago | (#33910200)

It is easer to deflect an asteroid that's far away. But isn't a big part of the problem getting the probe to the asteroid while it's _still_ far away? After the asteroid has been detected, the international agreements signed to do something about it, there's still the journey time of the probe getting there while it's still possible to do something useful.

The cost... (3, Insightful)

Dancindan84 (1056246) | about 4 years ago | (#33909904)

None of them want to pay taxes again. Ever.

Re:The cost... (1)

jason.sweet (1272826) | about 4 years ago | (#33910308)

That's fine. Just make sure they don't get the roughnecks from BP.

Re:The cost... (3, Funny)

Thud457 (234763) | about 4 years ago | (#33910452)

None of them want to pay taxes again. Ever.

I don't think a spaceshipload of teabaggers is going to be the right choice skillset-wise for effectively deflecting an asteroid. Can't we just put them on the B-Ark and fly them into the Sun?

Re:The cost... (1, Insightful)

Notquitecajun (1073646) | about 4 years ago | (#33910492)

Well, IF we had to land some guys on an asteroid to deal with it, would you want practical blue-collar types who aren't afraid to work with their hands and have the muscle to get stuff done, or techno-weenies pushing buttons and not able to deal with something on the outside if it breaks?

Not that it's quite that dichotomy, but those "teabaggers" you ridicule aren't as stupid as you think that their politics are.

Talking about the apocalypse... (3, Informative)

T Murphy (1054674) | about 4 years ago | (#33909906)

Speaking of the apocalypse: Of course doomsday predictions are always for a future date. It would be much more interesting if someone figured out a doomsday prediction for a date 3 years past. That would mean someone has to make a time machine to go back and warn them that the world is about to end. Knowing the world didn't end we could be certain that we will succeed in the time-travel mission.

This of course means that when the world does end it isn't our fault- it's the fault of the people from the future failing to post-predict the apocalypse and make a time machine to stop it.

ok, here's one (1)

hypergreatthing (254983) | about 4 years ago | (#33909920)

Just point the LHC at it and poof, asteroid immediately gone when it entered the event horizon of a miniature black hole that was created.

Re:ok, here's one (1)

MyLongNickName (822545) | about 4 years ago | (#33909966)

Nah. It would just continue on its route barely affected and now in black hole form. The positive is that it might pass through the earth with neither affected to much.

But what would such a mission entail? (0)

Anonymous Coward | about 4 years ago | (#33909924)

Nukes, and lots of them. Yeeeehhaaaww!

The best defense (1)

sunking2 (521698) | about 4 years ago | (#33909942)

Let's just nuke Klandathu first.

NO! (1)

snspdaarf (1314399) | about 4 years ago | (#33910226)

We must kill Leader Desslok!

Re:The best defense (2, Funny)

jpolonsk (739332) | about 4 years ago | (#33910316)

Would you like to know more?

solutions from the article (3, Interesting)

hAckz0r (989977) | about 4 years ago | (#33909948)

The mention both impact and gravity tractors, and both have their problems.

The "impact" method stands the chance of splitting the asteroid into man little pieces, and since that process of splitting absorbs energy less of it is available to deflect the body from its current course. To have enough mass going at a high enough velocity to contain enough energy to nudge it into a different trajectory you need heavy lift rockets with very fast final stage projectiles. The more velocity the more energy, but the more of that energy that will create debris that potentially causes even more problems. The best solution would be a very heavy object moving slowly, but the would be impossible to lift and deploy. Using nukes would allow a smaller projectile, but would very likely cause radioactive debris to renter earth's atmosphere. Not good. Its better to land on it and push it into the sun's gravity well.

The 'Gravity tractor' method requires just as much energy as pushing the asteroid, but you need LOTS of mass to make it work. Again you need heavy lift equipment to make this work, and I seriously doubt you can lift enough mass into space, and move it to where it needs to be, in time to effect the trajectory by much. You are still better off using that same fuel to get there quickly and push it lightly for a while into a new trajectory.

Re:solutions from the article (2, Insightful)

MozeeToby (1163751) | about 4 years ago | (#33910072)

Using nukes would allow a smaller projectile, but would very likely cause radioactive debris to renter earth's atmosphere. Not good. Its better to land on it and push it into the sun's gravity well.

I thought the idea for nukes was to set the off well away from the surface so that one side of the asteroid ablates off producing a net thrust. This is preferred because it doesn't waste energy breaking a large rock into smaller pieces, doesn't create debris, and can also be effective on 'rubble pile' type asteroids.

And of course, the biggest advantage for a nuke is that it's the densest form of energy storage that we have, you can send a nuclear warhead up for way less delta-V than an equivalent amount of rocket fuel, even if the nuke is only 40% efficient in terms of energy to thrust. But then I suppose you could have an Ion type engine that uses little propellent and gathers energy from solar panels or even a nuclear reactor. Find a way to use the asteroid itself as the propellent (mass driver), use energy from the sun, and the necessary automation to gather and process the rock and you'd have a very light weight solution (with the added advantage of setting up the first, prototypical asteroid mining facility).

Re:solutions from the article (2, Interesting)

sznupi (719324) | about 4 years ago | (#33910420)

Or solar sail. Or utilize Yarkovsky effect by spraying the object with paint and/or shading it & illuminating different parts of it (again, basically a sail). With so many possibilities, we should be fine - assuming early enough detection.

Re:solutions from the article (4, Interesting)

blair1q (305137) | about 4 years ago | (#33910628)

The ablation thing is inefficient. Use a nuclear reactor on the asteroid surface to melt itself down, melting a portion of the asteroid and directing it through the melt hole into space. You can send up a big reactor, use the asteroid itself as reaction mass, and get much more efficiency than a blast and an ablation.

As for "rubble pile" asteroids, those would tend to break up and explode in the atmosphere. The more you can disperse them before they hit the atmosphere, the better. So embed a nuclear bomb and explode it when it's a few days out, so it doesn't have time to reform.

Re:solutions from the article (1)

sznupi (719324) | about 4 years ago | (#33910306)

ESA has one nice analysis here [esa.int]

No, if early enough it doesn't require a very big mass at all, or some particularly asteroid-shattering impact (one other interesting, even if probably not particularly useful, method in the link above: centrifugal fragmentation; considering many asteroids seem to be barely held together rubble piles...)

Re:solutions from the article (1)

sznupi (719324) | about 4 years ago | (#33910334)

PS. Also, I'm curious, what exactly do you mean by "push it into the sun's gravity well"? It's constantly in it... virtually all the objects in our system are.

Re:solutions from the article (0)

Anonymous Coward | about 4 years ago | (#33910524)

Not "virtually all" objects are in the sun's gravity well, ALL objects in the universe are being "pulled" into the sun's gravity well. Most are dominated by other gravity wells, are so distant that the effect of the sun's mass is veeery minor or have a high enough velocity to escape it. Presumably what was meant by "pushing it into the sun's gravity well" is to lower it's orbital velocity enough that it actually intersects the sun's surface and is destroyed. This would require FAR more energy than to simply deflect it's path enough to miss the earth. And it seems mean-spirited as well... we don't have to vaporize the innocent rock, it didn't mean any harm.

Re:solutions from the article (0)

Anonymous Coward | about 4 years ago | (#33910608)

Using nukes would allow a smaller projectile, but would very likely cause radioactive debris to renter earth's atmosphere. Not good.

Oh great. Then the nuclear shockwave shatters the Phantom Zone and General Zod shows up. And since Superman took a spill from his horse, I'd rather take my chances with the asteroid.

Re:solutions from the article (1)

KJSwartz (254652) | about 4 years ago | (#33910670)

Impact has the best chance, in that a large number of "small" mass missles can travel at a high velocity and timed to impact for best effect. A jackhammer effect, or convert rotational energy in a manner to nudge the asteriod into a different orbit. Think COMSAT maneuver.

Re:solutions from the article (2, Interesting)

AmericanInKiev (453362) | about 4 years ago | (#33910682)

I suppose one should calculate of what materials the Asteroid is made, and determine the least material necessary to make a combustion from those materials. If, for example, the Asteroid is ice; one could land, then use sunlight to convert water into hydrogen and oxygen, then fire off jets at optimal moments in the rotation. This isn't very complicated, and we've already intercepted an asteroid.

Re:solutions from the article (1)

theBuddman (1905202) | about 4 years ago | (#33910732)

If the asteroid is sufficiently far away, it won't really matter if it splits into little bits or not. The fragments resulting from an asteroid that splits due to a violent impact are not going to remain on the exact same trajectory as the original asteroid. A slight deviation of trajectory far enough away results in a big miss back here at home. In fact, if it's far enough away, you don't even need explosives. You could continually accelerate (via ion engine) a moderately sized projectile directly into the asteroid. The velocity would make up for lack of mass and should pulverize the asteroid. Resulting fragments would not be able to continue on the same trajectory due to the head on impact. Again, all this depends on the distance.

Mad Scientist Solution (0, Redundant)

Ukab the Great (87152) | about 4 years ago | (#33909968)

CERN could create black hole in front of the earth that would suck down the asteroid. To hell with detractors and their "drawbacks". Haters gonna hate.

Planning and preparation (1)

dredwolff (978347) | about 4 years ago | (#33910020)

I think this is a great idea. Not only should we come up with good theories, we should test the best one on an asteroid that is relatively close, and have the necessary preparations done for a future quick-launch mission in case this ever does happen.

Because, after all, the amount of time between when we hear about an asteroid on a collision course and when it would actually hit the planet is likely to be a LOT less than the amount of time it would take to ready a space mission (or build a special rocket, or borrow China's anti-satellite laser!)

Armchair astronomy (1)

MobyDisk (75490) | about 4 years ago | (#33910030)

The article suggests two approaches:

...a kinetic impact would roughly “push” the asteroid into a different orbit, and a gravity tractor would “tug slowly”...by using nothing more than the gravitational attraction between the two bodies.

I didn't think we could produce enough kinetic energy to affect anything large enough to be a threat. Similarly, I would be surprised if we could get any significant mass into space to attract it via gravity. Am I totally off-base here? It seems to me that we would need to rely on either 1) nuclear power or 2) external power (solar?) to have any significant impact. For example: attach a solar sail to the asteroid to slow it down or change the direction. Or a solar-shield that might cool one part of the asteroid and change the orbit. Or a nuclear blast to push it.

take a nuke to it (0)

Anonymous Coward | about 4 years ago | (#33910046)

The path of the object should be very predictable. All you have to do is either annihilate it or move it off its course. At the scale of distances, even a .1% shift should have pretty significant impact. Of course, this assumes we see it coming far enough out to attempt such a feat.

The Earth would be fine (2, Insightful)

MadTwit (1918654) | about 4 years ago | (#33910064)

...we wouldn't.There is no possible threat to the Earth which humans could ever make even the smallest abount of diffence about. Instead there is a threat to civilisation. Pedantic, I know but the only threat to the earth is crashing into a star or another planet. Humanity compared is much more fragile, threatened by a mere mile wide rock or similar.

Re:The Earth would be fine (1)

sexconker (1179573) | about 4 years ago | (#33910278)

...we wouldn't.There is no possible threat to the Earth which humans could ever make even the smallest abount of diffence about. Instead there is a threat to civilisation. Pedantic, I know but the only threat to the earth is crashing into a star or another planet. Humanity compared is much more fragile, threatened by a mere mile wide rock or similar.

Your post sneakily mocks the global warming crowd.
This makes your post better.

Nukes (1)

Geoffrey.landis (926948) | about 4 years ago | (#33910148)

People hate to admit it, but this really is a mission that is best done with nuclear explosives.

Not to "blow it up," no-- but to produce an impulse to nudge it onto a slightly altered course, a surface nuclear blast is about the best technique you can think of. Nukes have extremely high energy to mass ratio. And, despite what Hollywood would have you think, you don't need to have Bruce Willis dig a hole in the asteroid to plant it.

Some analysis is needed to make sure that you nudge the asteroid, not fragment it. Nevertheless, it's hard to beat the efficacy of a nuclear explosion.

Re:Nukes (2, Funny)

jpolonsk (739332) | about 4 years ago | (#33910382)

What, the movies have lied to me? Next you'll be telling me that you can't enhance a photo so many times that you get more information from a reflection in it then was originally taken.

Re:Nukes (2, Interesting)

sznupi (719324) | about 4 years ago | (#33910666)

Nukes provide just a very short impulse; transferring it to the whole rubble pile might turn out to be problematic.

Gravity tractors (and few other methods) can work months, years; and force from them works uniformly (or in the case of some other methods - very gently)

If... (0)

Anonymous Coward | about 4 years ago | (#33910208)

...the Dragonriders of Pern can move a planet, we can move a little rock.

Send in BP (1)

srk2040 (973509) | about 4 years ago | (#33910262)

We could always send BP to drill on the asteroid but then again, they would probably end up with a rig explosion and everyone on earth would get screwed.

Gorath - 1962 (2, Informative)

AmigaHeretic (991368) | about 4 years ago | (#33910276)

I thought this was already solved?
You don't move the asteroid... you move the Earth! With lots of giant hydrogen powered rocket tubes at the South Pole!

http://www.youtube.com/watch?v=mf2lvRStVdg [youtube.com]

Re:Gorath - 1962 (0)

Anonymous Coward | about 4 years ago | (#33910376)

It's interesting that all the pimply faced kids posting here think that Bruce Willis and the Armageddon movie was the first time any body thought of or made a movie about how we might avoid an asteroid collision.

What? You old farts had telescopes in 1962!?!? But we hadn't even gone to the moon yet though. What? Trying to solve how to prevent the destruction of the Earth from extraterrestrial objects has been going on since before 1998!?!?

Get off my lawn!

sad but true. (1)

Buzzsaw5 (1047078) | about 4 years ago | (#33910324)

Our "leaders" would try to deflect the asteroid with their best weapons: denial, filibustering, finger pointing, libel, slander, bribery, blackmail, and a congressional hearing in which the asteroid is badgered and vilified.

Re:sad but true. (1)

blair1q (305137) | about 4 years ago | (#33910636)

Those don't actually solve the problem. As usual.

Best solution (1)

Psicopatico (1005433) | about 4 years ago | (#33910394)

Send in a spacecraft packed with lawyers threatening to sue if that doesn't change its course.

Double win!

How to move asteroids. (2, Insightful)

kurokame (1764228) | about 4 years ago | (#33910416)

You find out its orbital and mechanical properties as early as possible.

Then you send a gravity tug to change the orbit.

Very interesting (0)

Anonymous Coward | about 4 years ago | (#33910486)

Last time this happened it wiped out the dinosaurs, paving the way for us... Who are we now to decide what may or may not happen to the future of life itself on this planet? If you say we have have evolved intelligence and we should use it, you can't be against life extension technology. Oh Space Nutters, what is it this time? "Go technology!" except when extending life?
Big, beefy penis rockets: YES
300+ years of youth: UNNATURAL!!! WAHHHH!!!!!

Lasers and aliens (1)

joshier (957448) | about 4 years ago | (#33910556)

Here's s couple thoughts: if we had a powerful laser, could we zap it? What about putting some infective virus like nanobots that eat in at the asteroid.

Also, if we detect an asteroid that's big enough to destroy us all and nothing destroys it for us, we will know aliens aren't here trying to protect us for some reason.

The mars rover was 'an asteroid' but we .. (1)

joshier (957448) | about 4 years ago | (#33910620)

The mars rover was 'an asteroid' but we protected it, so couldn't we wrap some cushioning around it so when it lands it has a cushion of sorts. Or what about covering it with some highly reactive material so when it enters earths atmosphere, it burns up quicker than normal?

might be worthy to (0)

Anonymous Coward | about 4 years ago | (#33910694)

Have a backup plan...

ETA: 2 days (3, Informative)

gmuslera (3436) | about 4 years ago | (#33910730)

The last 2 discovered asteroids that passed "close" (at least, closer than the moon, the last one was few days ago at 45k km) were found with very few days in advance. They weren't very big, but still could had done some big damage, and the early warning wasnt enough to even think on launching a ship, much less doing anything effective with it.

Early detection must be improved... that some of the asteroids that we know could take 15 years to get here and so give us enough time to prepare don't mean that some unknown or even known ones (if you want, because somehow changed its orbit) could be in its way here and detected when is already too late.

wouldnt it be easier to... (2, Funny)

Rivalz (1431453) | about 4 years ago | (#33910736)

I think we are looking at this the wrong way. We should instead be trying to turn the moon into our own deathstar. That way we can change its orbital position to deflect or intercept the asteroid. That way we get multiple uses out of it and can also rule the solar system once our deathstar becomes fully operational. How hard would it be to put enough rockets on the moon to be able to drive it around... Seriously NASA WTF are you guys doing trying to land a little rocket on a asteroid when you could be asking for funding to drive the Moon.

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