Ask Slashdot: Best Payloads For Asteroid Diverter/Killer Mission?

TheRealHocusLocus writes: The Emergency Asteroid Defence Project has launched a crowdfunded IndieGoGo campaign to help produce a set of working blueprints for a two-stage HAIV, or Hypervelocity Asteroid Intercept Vehicle. This HAIV paper (PDF) describes the use of a leading kinetic impactor to make a crater — a following nuclear warhead would detonate in the crater for maximum energy transfer. The plans would be available for philanthropists to bring to prototype stage, while your friendly local nuclear weapon state supplies the warhead. This may be a best-fit solution. But just ask Morgan Freeman: these strategies could fail. What — if any — backup strategy could be integrated into an HAIV mission as a fail-safe in case the primary fails? Here is a review of strategies (some fanciful, few deployable) if we have to divert an asteroid with very short lead time. A gentle landing on the object may not be feasible, and we must rely on things that push hard or go boom. For example: detonating nearby to ablate surface materials and create recoil in the direction we wish to nudge. Also, with multiple warheads and precise timing, would it be possible to create a "shaped" nuclear explosion in space?

Comments

In defense of the human race

[TheRealHocusLocus]

Discovery of an underwater skeleton 'tea party' in the Colorado River provides ample proof that the human race is worth saving.

Re:In defense of the human race

[JaredOfEuropa]

That is just too funny. In the same spirit, I suggest we send up Celine Dion and Justin Bieber on that asteroid buster mission. They won't be of any help when things go wrong, but if the primary mission succeeds, we will not only have won back out world, we will have made it a better place.

Re: In defense of the human race

[jd2112]

Nothing against Canadians in general, just the really annoying ones.
Can we send Donald Trump as well? Let's keep his hair here as a warning to future generations though.

Re:In defense of the human race

[Runaway1956]

You're pretty obviously not Canadian. Real Canadians won't own bieberhead as their own.

Re:In defense of the human race

[marcello_dl]

We have a winner.
If you send Celine Dion and Justing Bieber up on an incoming asteroid, it will steer away on its own.

Re:In defense of the human race

[Somebody Is Using My]

But by that logic one could argue the reason we haven't been hit by a big asteroid is /because/ Bieber and Dione are here on Earth. The asteroids have been steering clear of us rather than risk contamination. Ship Bieber/Dione out into deep space and we lose that protection!

Then again, it might be worth it...

Re:In defense of the human race

[marcello_dl]

Don't worry, we still have nickelback and one direction.

nothing will work.

[turkeydance]

the dinosaurs tried everything.

Re:nothing will work.

[TheRealHocusLocus]

They did duck and cover under about 40-100 cm of moist dirt, thus saving the most gentle of the flock from the global pizza or roasting oven of falling impact debris. KT-event: the most delicious of the apocalypses.

Ten thousand billion tons of ejecta, ~30 x Mount Everest. Effects of the KT impact event presented by Rusty Schweickart. ~1 meter of the world's oceans boiled off. 70% of all life wiped out. Bad scales and feathers day. Good mammal hair day. If you like Hollywood panic and CGI, Evacuate Earth and Catastrophe/4: KT

Think on how great it would feel to stop something like that from happening again.

Re:nothing will work.

[Triklyn]

let the world burn. it would certainly make for an interesting tuesday.

Re:nothing will work.

[TheRealHocusLocus]

let the world burn. it would certainly make for an interesting tuesday.

Tuesday Afternoon
Where's The Walrus?
Fly Like An Eagle
Tomita: Planets

The Tea Party

[Rinikusu]

I'd love to see them fly into an asteroid.

Re:The Tea Party

[TheRealHocusLocus]

I'd love to see them fly into an asteroid.

Great idea! In the spirit of the underwater skeleton 'tea party' in the Colorado River, in tribute to the artist -- space permitting -- it would be really cool if a large unmanned asteroid intercept vehicle could have a windowed 'bridge' with a pair of plastic skeletons seated in lawn chairs. Their grinning skulls would be the last thing that nasty old space rock ever sees.

You get points for style.

Giant rockets on the moon

[Megahard]

Then when an killer asteroid is found, just push the moon in the way.

(Yes, I know that can't work. But it won't stop Hollywood from using it in a movie.)

How would nukes exert force on an asteroid?

[myowntrueself]

In atmosphere, nukes produce blast because of high energy x-rays igniting atmosphere. This won't happen in space.

So how would letting off a nuke near or on an asteroid produce reaction and change the course of the asteroid?

Re:How would nukes exert force on an asteroid?

[Anonymous Coward]

The Orion project looked at how to push a large object with an explosion in a vacuum.
Project_Orion_(nuclear_propulsion)

Re:How would nukes exert force on an asteroid?

[fisted]

A solar sail on an asteroid to change it's trajectory? You can't be serious.

Re:How would nukes exert force on an asteroid?

[painandgreed]

In atmosphere, nukes produce blast because of high energy x-rays igniting atmosphere. This won't happen in space.

So how would letting off a nuke near or on an asteroid produce reaction and change the course of the asteroid?

Basically, the x-rays will ignite the surface of the asteroid instead. If the material in the asteroid is sub-optimal for this purpose, there have been designs of turning a nuclear bomb into a kinetic weapon that should work in this regard. Basically the bomb sits in an x-ray reflective shell, and when the bomb explodes, the x-rays bounce around the shell before the exploded bits of the bomb destroy it and exit an aperture. At the end of the aperture is a large, dense block of x-ray absorbing material. This material is vaporized by the x-rays and is all traveling in a similar direction as the x-rays were all going in that general direction. This plasma moving at relativistic speeds then slams into the target like a nuclear shot gun blast. IIRC, this design was built for using nuclear bombs against space ships and it was estimated that it could direct 95% of the energy of the bomb at the intended target.

Re:How would nukes exert force on an asteroid?

[myowntrueself]

In atmosphere, nukes produce blast because of high energy x-rays igniting atmosphere. This won't happen in space.

So how would letting off a nuke near or on an asteroid produce reaction and change the course of the asteroid?

Basically, the x-rays will ignite the surface of the asteroid instead. If the material in the asteroid is sub-optimal for this purpose, there have been designs of turning a nuclear bomb into a kinetic weapon that should work in this regard. Basically the bomb sits in an x-ray reflective shell, and when the bomb explodes, the x-rays bounce around the shell before the exploded bits of the bomb destroy it and exit an aperture. At the end of the aperture is a large, dense block of x-ray absorbing material. This material is vaporized by the x-rays and is all traveling in a similar direction as the x-rays were all going in that general direction. This plasma moving at relativistic speeds then slams into the target like a nuclear shot gun blast. IIRC, this design was built for using nuclear bombs against space ships and it was estimated that it could direct 95% of the energy of the bomb at the intended target.

Thanks, thats a nice explanation!

Re:How would nukes exert force on an asteroid?

[TheRealHocusLocus]

Basically, the x-rays will ignite the surface of the asteroid instead. If the material in the asteroid is sub-optimal for this purpose, there have been designs of turning a nuclear bomb into a kinetic weapon that should work in this regard. Basically the bomb sits in an x-ray reflective shell, and when the bomb explodes, the x-rays bounce around the shell before the exploded bits of the bomb destroy it and exit an aperture. At the end of the aperture is a large, dense block of x-ray absorbing material. This material is vaporized by the x-rays and is all traveling in a similar direction as the x-rays were all going in that general direction. This plasma moving at relativistic speeds then slams into the target like a nuclear shot gun blast. IIRC, this design was built for using nuclear bombs against space ships and it was estimated that it could direct 95% of the energy of the bomb at the intended target.

I second that. Masterful tech writing.

This description of Orion propulsion also describes the 'Casaba-Howitzer', a one-shot Orion optimized for a narrow, fast plasma jet. Here objective is more similar to Orion than punching through armor: the most complete, reliable and (as much as possible) directed transfer of energy. The Casaba-Howitzer concept is not even in the declassified SDI flava stuff that DOE is permitted to talk about.

We all love Delta-V-expensive solutions that involve maneuvering 'beside' or 'landing on' a threat (which by definition is heading straight towards us at 10-30kps. There are no cloverleafs in space, people! :) Landing Bruce Willis is out. Doing anything gentle or slow is out. I propose these be shelved for the 'Emergency' context. Parameters are strict. The best we might achieve is some 45 or less approach angle. By this I mean the vehicle's course, the explosion can be directed broadside, as timing allows. The final sequence of events requires precise micro/nanosecond timing. We know our computers are up to it.

Are the warheads? We know how to make warheads that detonate on timing, pressure and 'contact'. But speed is relative and conditions in atmosphere is a cushy affair, a device falling at terminal velocity or missile propelled. Can we assuredly produce a weapon that can range itself accurately or trigger in vacuum, on or just before contact at ~40kps?

And there should be at least three complete missions of them en route, each lagging far enough to escape detonation effects, have enough time to analyze a failure, upload firmware, or adjust course in case we have partial success. And it would br really nice if each mission embodied more than one general approach, or the ability to reconfigure for an alternate strategy... just in case there it becomes clear after the first that the primary will not work. And even an idea that shapes force of a nuclear explosion is a massive fail if a technical snafu has it pointing the wrong direction.

The price of failure is death. And embarrassment.

Moon rocks

[Anonymous Coward]

You need a moon base (not manned) to do this right. Then you throw moon rocks at the impending impactor. Doing it from a smaller gravity well means you can sling them into space more easily via something like a magnetic rail gun (yes, you need to put the moon rocks into a container made of iron / steel so it works with a mag solution).

Re:Moon rocks

[TheRealHocusLocus]

You need a moon base (not manned) to do this right. Then you throw moon rocks at the impending impactor. Doing it from a smaller gravity well means you can sling them into space more easily via something like a magnetic rail gun (yes, you need to put the moon rocks into a container made of iron / steel so it works with a mag solution).

+1 Insightful

A series of mass-produced kinetic impactors launched from the lunar surface by an EM rocket sled, each a ferrous metal cylinder containing lunar regolith with some propellent, attitude jets for course correction, (perhaps) a main engine for additional impact velocity. The probability of several or many reaching target is high. I give you a gold star. We could even retaliate against Mars.

It could be used to target Earth too, let's hope to be mature enough to resist. And hopefully its accuracy is better than Popeye's Pappy as he attempts a warning shot across the bow.

Re:Moon rocks

[dwywit]

"The moon is a harsh mistress" is a good reference for this.

Re:Moon rocks

[UttBuggly]

Indeed...good book.

Re:Moon rocks

[TheRealHocusLocus]

...and how do you propose to BUILD any of this perennial childish sci-fi nonsense?

With our hands, making less than minimum wage. The robots will be busy taking over our jobs on Earth.

The Chinese/Russians/South Koreans will probably be on the moon by 2040, Japan plans an unmanned base by 2020 and Japan/India announced intent to have a permanent base by 2030 but more likely a decade later. A study in grey. Bear in mind that these are visible nation-states but there will be also be an invisible multinational corporate hand behind the early adopters. There will also be a forward-thinking billionaires practicing their Mandarin, Russian and Japanese in the mirror because they're fed up with endless politics.

Notice I didn't pair up the United States with anyone for Lunar exploration, because way things have been going we'll probably be paired up with Iran, Syria, Libya, Lebanon, Somalia and (post-revolution) Saudi Arabia, Pakistan and Morocco, (and still) Iraq and Afghanistan to make portions of Earth more closely resemble the surface of the Moon.

Re:Moon rocks

[quenda]

It is easy to get out of the earth-moon gravity well from the moon with a sled, but your load will still be stuck in a solar orbit similar to the Earth's.
To divert an asteroid, you would need to catch it early, on a near-miss pass of the Earth, and even then the orbit will still intersect our orbit.
If we detect a large object on a direct collision course, launching rocks at it from the moon is about as useful as throwing rocks by hand at an incoming ICBM.

Re:Moon rocks

[Antique Geekmeister]

ICBM's have guidance systems. Asteroids and comets do not, and space is _large_. Even a very, very slight "delta vee" early in the trajectory will make it miss a planet quite easily.

How about

[no-body]

Confetti
?

Re:How about

[TheRealHocusLocus]

Confetti?

Yes, confetti has been is proposed. Tony [Zuperro? Curse you Discovery for no proper screen credit] has an interesting but incredibly elaborate idea that involves maneuvering a million tons of dust into the path of an object.

Gravity Tug

[stevelinton]

If you have enough lead time then I think the gravity tug works well. You rendezvous with the asteroid and fly alongside it, using solar-electric or some other slow but mass-efficient drive to hold station on the same side of the asteroid. The gravity of the probe VERY SLOWLY accelerates the asteroid and over a few decades (perhaps with a few refueling missions to bring more xenon or whatever) the asteroid's orbit is changed enough to miss the Earth,.

Re: Gravity Tug

[wagnerrp]

What do you think a "solar-electric" drive would be?

Re:Gravity Tug

[stevelinton]

Worth considering if the asteroid doesn't rotate too much or in the wrong plane.. However you can get a much higher momentum/energy ratio by using a reaction mass that is expelled at a few tens of km/second, rather than light.

A large load of sheets from BB&B

[sphealey]

NASA's current plan it to cover a sufficient amount of the object with a different colored cloth (white or black as the case may be) and let the solar sail effect do the work. So a 30% off coupon to Bed Bath & Beyond would do the trick; even with the discount the manager and staff should get a nice bonus for selling 250,000 white sheets in one day.

sPh

Re:A large load of sheets from BB&B

[BigFootApe]

Only works if the asteroid cooperates by not tumbling.

Re:A large load of sheets from BB&B

[Antique Geekmeister]

You can get a much, much larger effect by attaching a much larger, more easily manufactured and testable actual solar sail. Either approach has interesting difficulties if the object is tumbling, since the attachment points for a solar sail or an actual elevated shield would need to be at the axes of rotation with joints that can handle spinning. And any mishandling of the forces could change the tumbling and cause the object to precess. But that seems far, far simpler than stopping the tumbling completely: that would require far more fuel and complex ongoing course corrections. And the resources to control tumbling might be easily overwhelmed by uneven melting and outgassing from any comet like body.

In fact,please permit me to revise my earlier suggestion of tilting the light sale to steer. Caught early enough, I think that a large solar sail providing even a small amount of solar braking would work just as well, with less complexity, to avoid an Earth impact. Delta vee is delta vee, and unless it were applied miraculously precisely to re-aim the dangerous body at Earth, even a random thrust should be enough.

Re:A large load of sheets from BB&B

[RockDoctor]

You can get a much, much larger effect by attaching a much larger, more easily manufactured and testable actual solar sail.

How are you going to do that attachment again? The attachment mechanisms for Philae worked spectacularly well given the amount of information that was available about the comet's surface structure ten years before contact. So we can realistically anticipate a similarly accurate degree of knowledge about the surface properties of the asteroid we need to manage in two years time.

Next suggestion?

Re:A large load of sheets from BB&B

[Antique Geekmeister]

Philae did not have to apply significant force to the comet itself, especially applying consistent force as the comet itself melts, and to consistently apply force to the same side of the comet. Even if a solar sail is applied purely as a solar powered brake, the tumbling of a comet or asteroid will require that the attachment points be able to _spin_, and not to tangle the shrouds of the solar sail on the tumbling object itself. If the spin of the object has an axis on the side away from the Sun, it should be possible to attach there.

There are profound issues of how to attach robustly and avoid fracturing a comet, leaving a potentially deadly remainder still on target for Earth, if it is a porous, frozen object. I'd anticipate significatnt sublimation and thawing on even the backside if the solar sail does not reflect _away_ from the object. But the idea provides far more available thrust and control than draping coverings directly on a tumbling asteroid or comet.

Re:A large load of sheets from BB&B

[RockDoctor]

I'd anticipate significatnt sublimation and thawing on even the backside if the solar sail does not reflect _away_ from the object.

Since at least some comets that cross Earth orbit (and are therefore a threat) have had insignificantly altered orbits for several thousand years and dozens of perihelia, then the lower limit of sublimation you're going to need to consider is under 1% per apparition. Even with a solar sail blasting the backside with essentially another Sun, you're still down in the 2% per apparition or lower range. (I'd guess lower). Comets on a sun-diving orbit are approximately half the threat of ones that don't sun-dive. The sun-divers don't get a second chance to hit the Earth.

But the idea provides far more available thrust and control than draping coverings directly on a tumbling asteroid or comet.

I agree on this point. But since the proposal is for a generic design to deal with any incoming impactor, be it comet, asteroid, or even generation ship, then a design that can handle any impactor without modification is needed. There won't be time to design a modification if it is actually needed.

Re:A large load of sheets from BB&B

[Antique Geekmeister]

> I agree on this point. But since the proposal is for a generic design to deal with any incoming impactor, be it comet, asteroid, or even generation ship, then a design that can handle any impactor without modification is needed. There won't be time to design a modification if it is actually needed.

And this is where I would say _what!!???_ at lest if we were in person. "Any incoming impactor" includes objects of such potentially high kinetic energy, and of such unlikeliness, that we cannot even include it in any practical discussion. That includes, for example, intrastellar planetary bodies, "rogue planets". And that is where such a discussion would need need to assess, right from the start, trade-offs of likelihood of combinations of mass, velocity, and lead time to deal with it.

This was played out in the Rosetta Comet mission, which did _not_ succeed in embedding anchors in the cometary surface. Expecting a single design to handle both intra-solar-system objects, such as those from the Astroid Belt and of much smaller relative velocity to the Earth, and a cometary body that could be expected to be far, far colder and of a much larger relative velocity.

So right there, in the necessary requirements, are two profoundly distinct missions that might require two very distinct designs. Let's not limit such a discussion from the start in a single idea or technology that _must_ handle both.

ask Slashdot

[Fnord666]

Any chance that you might consider posting "Ask Slashdot" articles in the "Ask Slashdot" section in the future? Please?

Re:ask Slashdot

[TheRealHocusLocus]

Any chance that you might consider posting "Ask Slashdot" articles in the "Ask Slashdot" section in the future? Please?

I believe the proper forum for this question is "Ask Slashdot". Please re-post your question there.

ablation by laser

[bzipitidoo]

Beam enough laser light at the object to heat its surface to the point that it ablates. That will push it onto a different course. We won't even have to leave Earth for that to work. Of course, it does need an awful lot of laser power, but if our very survival is at stake, maybe we could do it. Here's the relevant XKCD what if.

Re:ablation by laser

[TheRealHocusLocus]

Beam enough laser light at the object to heat its surface to the point that it ablates

Another extreme light solution, also reliant on melting its surface are giant parabolic mirrors deployed near the object. This interesting discussion points out some of the realities of gathering and focusing sunlight.

Once our civilization hits Stage 1.5 on the Kardashev scale we might revisit an idea proposed in 1993 by Paul Birch, How to Move a Planet through the use of what he calls a 'solar windmill' to transfer angular momentum between the sun and planets. It's Rube Goldberg as hell!

"We conclude that through the use of high-velocity dynamic compression member to apply forces efficiently, planetary orbits can be modified on convenient engineering timescales ~30 years, that the cost of such operations is not excessive in conjunction with terraforming or artificial-planet-building projects, that energy can be converted to and from orbital energy with little loss, and that the technique may also apply to the regularisation of stellar motions."

Then we could just bob the Earth and scoot it out of the way. If lowly earthworms are deserving of our protection, surely an asteroid may be.

Re: Nuclear waste

[camperdave]

Come now. How and why would we shoot Venus and Mercury into the Sun?

Obviously

[rossdee]

Bruce Willis

Why not a type of Bola?

[Vonotar82]

How about shooting some tethers at it and deploying a counter-weight (rocket-powered?) to the object to swing it out of orbit? Make it into a Bola?

Re:Why not a type of Bola?

[TheRealHocusLocus]

How about shooting some tethers at it and deploying a counter-weight (rocket-powered?) to the object to swing it out of orbit? Make it into a Bola?

David French proposes Trajectory Diversion of an Earth-Threatening Asteroid via Massive, Elastic Tether-Ballast System [2010], although the time frame for the large objects he modeled was upwards of a decade. But IF you do have decades and the materials challenges of the tether (bluntly pointed out in Wired Magazine [2009]) are solved, it offers a low-tech solution that would not require constant vigilance or active control.

Or a massive light saber flung with a cosmic atlatl.

Re:Why not a type of Bola?

[weilawei]

The object is likely spinning. I'd want to eliminate the tether, which is huge point of failure. While static loading isn't as big an issue, shock loading IS a big problem, and it's unlikely we'll be able to entirely prevent it, or it will be prohibitively expensive in terms of mass (fuel for burns to slowly load the tether). Either way, you'll need to match the spin (i.e., orbit around) the object in order to eliminate the relative motion.

Also, I have no idea how much force you would need to perturb the orbit sufficiently. If you were still spinning, you would only be able to fire the engines for a portion of your orbit. You might actually use that to stop the spin, and then drag it higher/lower in its orbit. In any event, you would need the required force to be less than the maximum static load on your tether multiplied by the fraction of the time you can actually burn the engines.

IANAAE (I am not an aerospace engineer). You probably shouldn't actually try anything I suggest.

Impactor efficiency versus rocket payload?

[Kevin Fishburne]

Would it be more efficient to launch an impactor from Earth to change the asteroid's trajectory or to launch a rocket (using the same rocket that would launch the impactor) carrying a second rocket that would attach to the asteroid and burn to similarly change its trajectory? An impactor would need to be calculated precisely in advance, while attaching a rocket would allow some room for error since its burn could be controlled remotely. The actual feat of getting the rocket to land and securely mount itself would be a challenge however. I don't think "blowing it up" is a good idea, but diversion if possible seems the least-risky and most-effective method.

Re:Impactor efficiency versus rocket payload?

[garyisabusyguy]

Paint

Paint one side of the object white and it will change its orbit

This would work with anything that we catch a few years out and would even produce results that could be calculated

Sure, it is not as exciting as blowing shit up, but way more effective

Re:Impactor efficiency versus rocket payload?

[flink]

Would it be more efficient to launch an impactor from Earth to change the asteroid's trajectory or to launch a rocket (using the same rocket that would launch the impactor) carrying a second rocket that would attach to the asteroid and burn to similarly change its trajectory? An impactor would need to be calculated precisely in advance, while attaching a rocket would allow some room for error since its burn could be controlled remotely. The actual feat of getting the rocket to land and securely mount itself would be a challenge however. I don't think "blowing it up" is a good idea, but diversion if possible seems the least-risky and most-effective method.

Just my take, but: If you want to land on it instead of crashing, you have to carry a bunch of extra fuel to burn off the delta-V that got you there in the first place. If you have enough extra fuel to slow down, you might as well burn it getting there faster so you have more energy when you impact. Essentially if you slow down to land, you're wasting a bunch of energy in the form of the ship's momentum which you could be putting into changing the course of the asteroid.

Hmm

[koan]

Multiple war heads detonated in a timed fan or "J" shape (asteroid on inside of curve) each adding more angular velocity.

Radioactivity is less of a concern than a large strike on Earth's surface.

I think the concern is moot though, the defrosting of Siberian tundra and other "accelerated" green house gas emissions, the acidification of oceans and the loss of most, if not all, of Earth's rivers will reduce the human population to the point this would not be possible.

Unless a strike is imminent.

Re:Hmm

[weilawei]

Not quite what you suggested, but I had the amusing idea of spinning the thing up until it can't hold itself together. Probably not feasible and probably not a great idea if you don't manage to break it into small enough chunks...

Re: Hmm

[weilawei]

You grossly misunderstand. You wouldn't surround it with something, but stick a rocket on it (possibly two, like a spinning wheel firework) and accelerate it in the direction it's already spinning. No washing machine required, and the technology is almost simple as possible: anchor + rocket.

As for iron, you'd need to exceed the tensile strength+gravity of the material to begin with, which is already going to require an object spinning enormously fast. I DID say it was probably not feasible. It was just an amusing thought. Perhaps you should learn to read and separate serious suggestions from facetious ones.

Also, a nuke is highly unlikely to simply "evaporate" a large body. You might succeed in creating a cloud of large debris though, as plenty of objects are loosely held together to begin with.

What Else

[Guy From V]

Several hundred megatons of newborn kittens with milky whiskers.

Annihilation

[Ann Coulter]

Launch a similarly massed object at it made of antimatter.

Re:tennis rackets

[TheRealHocusLocus]

one million tennis rackets.

A tennis racket of sunlight, as in a change of albedo on part of an object's surface using a light colored mesh, has been proposed for Apophis [2036]. Looks promising for known longer term threats which require small adjustment. From the paper Predicting the Earth encounters of (99942) Apophis [2007] p.13,

"altering the energy absorption and emission properties of a few hundred square meters of its surface (i.e., a 40 x 40 m patch) as late as 2018 could divert Apophis from impact in 2036; that is, the currently unknown distribution of thermal properties across Apophis can make the difference between an impact and a miss. Implementations of such a deïection might include depositing materials on Apophis' surface similar to the Kapton or carbon-ïber mesh sheets being considered for solar sails. With areal densities of 3 to 5 g m^-2 420 to 700 kg of carbon-ïber mesh could cover ~35-100% of the surface of Apophis in material with an emissivity of 0.4 to 0.9. For Kapton, static charge build-up in thematerial or asteroid due to solar UV exposure could aid deployment to the surface in such a low gravity environment. If an actionable hazard is found to exist, it would be necessary to move an object's entire uncertainty region (not just the nominal trajectory) away from the Earth. To provide margin adequate to cover all unknowns for Apophis, larger albedo modiïcations might be required. The modiïcation required will therefore depend on the predicted size of the trajectory uncertainty region in 2036 and thus on the asteroid's physical properties."

Something tremendously powerful

[bugs2squash]

Maybe a chuck Norris body part, fingernail clipping, chest hair something like that to bring the asteroid to its knees. Or simply beam a chuck Norris TV show at it, make it just not want to come here.

Re: Nuclear waste

[davester666]

To show Russia we mean business.

Spring clean up...

[sls1j]

The White House, and Congress

Solar sail with a modest angle to the sail

[Antique Geekmeister]

Solar sails are light payload, the forces involved are modest and cumulative rather than requiring a single controlled thrust under extreme circumstances, and need only modest anchorage or very modest netting to attach to the asteroid. They can provide continuous thrust for the lifespan of the sail, rather than a single high energy event, so they're much safer to build and to handle and much, much safer to test. Attached early enough, they should easily shift an asteroid or comet enough to avoid a crash. And properly constructed, they could be used to guide the object to almost any orbit desired, including guiding it to L4 or L5 to be a resource.

Nuclear Shaped Charge

[ka9dgx]

Yes, it is entirely possible to create a nuclear shaped charge. The Orion project was going to use quite a bit of them to launch a spacecraft with a payload of 6100 Tons to 300 Mile Low Earth Orbit.

Re:Nuclear Shaped Charge

[BigFootApe]

Impulse is provided by soft X-ray ablation. X-ray production and dispersal can be tuned by:

X-ray window on the radiation case
The majority of the radiation case is lined with standard X-ray reflector material. An area of the radiation case is more X-ray transparent, giving some directionality to X-ray radiation previous to explosive dissassembly of the device.

X-ray lasing medium
Lasing rods are installed on the device to selectively produce X-ray photons when energized by a nuclear detonation, again previous to explosive dissassembly. See Project Excalibur.

Assuming you are not just trolling.....

[robbak]

It is very difficult to 'shoot something into the sun'. You first need to get it out of the Earth's gravity, and then you need to decelerate it by 20 km/sec.

This is, frankly, impossible. You might be able to put a small payload to the sun if you used a very big rocket, and did a Venus fly-by. This way you could dispose of a few kilograms at a cost of a few hundred billion dollars.

Re:Assuming you are not just trolling.....

[TheRealHocusLocus]

You used the word "impossible" in relation to something space-related, Space Nutter Central Command is already a beehive of activity as nerds put up the 1960s space posters and prepare the proper religious rites to send out responses...

Don't forget the Theremin Spaaace Music and especially that mechanical clicking sound as Robbie The Robot prepares to speak. We Space Nutters love it because it reminds us of an Olivetti adding machine.

Point out something makes no physical sense, 99 times out of a hundred you'll something along the lines of "on my desk is a computer with a 3TB hard drive". Etc etc etc

I'm with you there. Until we do something astoundingly new and amazing with our technology, miniaturization (even Moore's Law) is an angels on the head of a pin exercise. Tech stocks will probably be flying high on the day of the 'next' KT impact.

Re:Assuming you are not just trolling.....

[iwbcman]

It is very difficult to 'shoot something into the sun'. You first need to get it out of the Earth's gravity, and then you need to decelerate it by 20 km/sec. This is, frankly, impossible. You might be able to put a small payload to the sun if you used a very big rocket, and did a Venus fly-by. This way you could dispose of a few kilograms at a cost of a few hundred billion dollars.

ok i'll bite, not being physicist I am curious what decelerating something by 20km/sec has to do with shooting something to the sun.

(first off I have no idea to whom or what you are responding, your post is not a marked as a response to someone else post, so I am not taking the side of whoever you were saying that to)

Rail gun tech has existed, since I was a child, capable of delivering a payload at escape velocities(40+ years ago-we know how, we just haven't done it). With a mile long track, I see no reason why we couldn't take all of our nuclear waste and fire it at the sun. Now I know this may sound ludicrous but there must be some reason why people have been talking about doing that since before I was born. I am genuinely curious as to why this is impossible or ungoldy expensive. Even given the outrageous military contracting cost, I can't imagine that we couldn't build such a rail gun for under a half a billion dollars. Beyond the costs of transporting the spent nuclear waste to the site, packing it something which would make it basically impossible for the contents to dump out in case of accident, I really don't see the massive expense. Sure firing the rail gun takes lots of power, but we run nuclear rectors on ships, so big deal. And because I am not a physicist I really don'tt understand what is so complicated here, if a payload leaves our gravity field at the right angle, the speed necessary to escape, is more than enough to assure smooth sailing straight into the damned sun.

Please enlighten me as to why this is "impossible".

thanks in advance

Re:Assuming you are not just trolling.....

[Frobnicator]

It is very difficult to 'shoot something into the sun'. You first need to get it out of the Earth's gravity, and then you need to decelerate it by 20 km/sec. This is, frankly, impossible. You might be able to put a small payload to the sun if you used a very big rocket, and did a Venus fly-by. This way you could dispose of a few kilograms at a cost of a few hundred billion dollars.

ok i'll bite, not being physicist I am curious what decelerating something by 20km/sec has to do with shooting something to the sun.

Because we orbit the Sun.

It would actually take less fuel to launch it to a distant star than to hit the nearby Sun.

We are orbiting the Sun. Anything we launch out of our orbit is also going to continue in the same path, similarly orbiting the Sun, and because it is small, drift away from the Sun. That can be leveraged to hit another star with minimum fuel consumption, although the journey would be long. Think along the lines of the Voyager probes or various other launches to locations beyond the planet.

If you want to hit the Sun you need to change its velocity so it is no longer in orbit of our star (slowing it down relative to Sun), and also push it firmly toward the Sun strong enough that it goes in. The star is not like a drain hole sucking things in, stellar winds and constant ejections push things out. It is not enough to get it outside Earth's orbit with a rail gun or other accelerator. Aiming for the Sun requires an enormous amount of energy, more than any single accelerator has made in human history.

Re:Assuming you are not just trolling.....

[iwbcman]

I won't pretend to completely grasp what you posted but I do really appreciate your answer, and I will add everything I learned about gravitational pull contradicts what you are saying, but my understanding of these things is, to put it politely, very, very limited. My naive understanding says that anything that approaches the orbit of any body in space , will be drawn in to that body by virtue of gravity, unless it has sufficient mass and momentum to maintain an orbit(ie. the moon, or satellites etc.) Given that the suns gravitational pull is many,many times greater than that of the earth(due to it's mass) I cannot imagine anything orbiting the sun without eventually being drawn in, unless it has sufficient mass/momentum to avoid the pull. So I guess you are saying that the probe we just crashed into mercury, had we moved it a bit more towards the sun(beyond mercurys tiny gravity) would have simply remained indefinitely in an orbit around the sun. Well i guess I learn something new everyday, thanks.

Re:Assuming you are not just trolling.....

[lucien86]

Sigh. To 'fire' something into the sun you need to decelerate it by 29 km/s to take it out of Earths orbit, then you need to accelerate it towards the star. A pretty expensive trajectory.

BTW anyone calling people at random 'space nutters' must be a cretin, probably humping their sister or Mum.

Re:Assuming you are not just trolling.....

[robbak]

Anything small that is (cosmically) near something big is in an orbit of that big object. Read that again. Then read on.

From here on, I will call the two things 'rock' and 'sun'.

We still call things going very fast as being in an orbit. We call these hyperbolic orbits, and this orbit carries the rock away from the sun after a single pass. These items have 'escape velocity'

Anything at less than escape velocity will be in a normal orbit. A normal orbit is not circular, it is an even, oval shape called an ellipse. The earth's orbit is nearly circular. We say that the earth's orbit has 'low eccentricity'. Its speed doesn't slow down or speed up much over its orbit. It stays at around 30 km/sec all year. A comet's orbit is highly eccentric. When it is far away from the sun, it moves very slowly. Then it falls toward the sun, gaining speed. But that little bit of movement it had caries it away from the sun, so it misses the sun. The sun's gravity pulls the comet around, flinging it back out where it came from. It slows down again as the sun's gravity pulls it back, until it slows down, turning, and falls back again.

So, let's examine your statement that "anything that approaches the orbit of any body in space , will be drawn in to that body by virtue of gravity, unless it has sufficient mass and momentum to maintain an orbit." There is something here that has created this understanding, the understanding that anything that is moving will be stopped by friction. Any movement soon stops. But what is there is space to make a rock stop moving? There is no air to slow it down, no carpet to rub against. Only if it happens to run into something else, and there is not much in space to run into.

Anything that approaches a body in space will be in an orbit.

There is also the understanding that small things stop easier than big things. But this is again tainted by the fact that your life has been lived on a planet, with air things have to push through and surfaces things have to rub against. Forget those things - there is neither in space - and small things keep going just as well as big things. The little thing has less momentum, but it also has less weight - the force of gravity on it - and the two things cancel out. In all orbital equations - as long as the 'rock' is much smaller than the 'star' - the mass of the rock cancels out, and is irrelevant. For our original premise - which was the idea of launching a payload of nuclear waste into the sun, by the way - the payload of waste and the earth follow the same equations - their wildly different masses are irrelevant.

What about when you throw a stone at your brother? That stone is an object near the earth. Surely it isn't in an orbit? Well - it is. It follows an elliptical path like anything else. It is like that comet, moving fairly slowly far away from (the center of) the earth, and it would continue in an orbit unless something - your brother, a window, the earth itself - gets in the way. If you could throw it at 8 or 9 kilometers per second (and if there wasn't any pesky air) it would remain in orbit, travelling right around the earth to hit you in the back of the head 90 minutes later.

So, what would we have to do to get a payload off the earth, and to the sun? First we would have to get it away from the earth, and that is not easy. But once it is away from the earth, it would still be orbiting the Sun. We would need to slow it down, almost to a stop - from 30km/sec down to zero. That is hard. Remember, there is no friction out there, no tyres on a road. You have to use a rocket engine pushing backwards, and it is just as hard to slow down in space as it is to speed up. The measurement of a space craft's ability to change speed is an important number, and is measured in meters per second - we call it the 'delta-V' of a spacecraft. The entire Saturn-V moon rocket had a delta-V of about 18 kilometers per second - without a payload. So magic a complete Saturn-V rocket away from earth, and it could get a tiny payload about tw

Re:Assuming you are not just trolling.....

[PPalmgren]

That would be the case...if it were stationary. The object on earth is stationary and then gets a lot of velocity imparted as it launches from earth...problem is earth orbits the sun at 67,000 mph. So to hit the sun, you have to neutralize a lot of velocity relative to the sun. The object put into space from the earth doesnt fall toward the sun, it is falling around the sun. The orbit wouldnt 'spiral in' by a small change in velocity, it jsut makes it elliptical like a comet.

Re:Assuming you are not just trolling.....

[Triklyn]

As Randall puts it, getting to orbital height isn't the hard part, it's getting to orbital speed.

https://what-if.xkcd.com/58/

things stay in orbit because they're going ungodly fast. That whole centrifugal force thing, our stuff up there is constantly falling toward the earth, and constantly moving so fast laterally that it's missed hitting the earth.

same for the sun, but bigger. the problem being, you shoot something out of orbit of earth fine... it's still moving ungodly fast, fast enough to miss hitting the sun though, and from what that guy up there is saying, the sun is actively pushing stuff away.

Re:Assuming you are not just trolling.....

[david_thornley]

Seems to me that, if you kill the orbital velocity, the Sun's gravity will do a perfectly good job of accelerating it towards the Sun. Not that this is easy, since 29 km/s is an awful lot of delta-v with our current technology.

Re:Assuming you are not just trolling.....

[TheRealHocusLocus]

What crazy thing those "Space Nutters" been up to today?

How 'bout dem Space Nutters, ain't they kooks?
Heads in the stars, readin' space booooooks!
Plannin' dem missions to launch men 'n probes
or spinny-dizzy colonies in LaGrangian lobes
wearin' them space suits on Halloween on Earth
chewin' the Space fat on for all that it's worth!
Dem nugger-mugger Space Huggers way down South
stuffin' Space Nutter Central for all that funds allow'th
How to be a Space Nutter, only one way to hack it
Get yerself a nuke, find an asteroid and smack it!

One in a growing series of 'them poem' tributes

Best Payload?

[Agripa]

Lawyers. Then we can get down to the business of building something to save us.

Re: Nuclear waste

[FatdogHaiku]

Come now. How and why would we shoot Venus and Mercury into the Sun?

It would make for awesome desktop background photos!

Re: Nuclear waste

[FatdogHaiku]

Forgot to say, ask Randall how... Something along the line of "What if I wanted to push a planet into the Sun?"
http://what-if.xkcd.com/

Magneto-nuclear asteroid steering

[Iamthecheese]

I like this idea better.

Morgan Freeman? Indiegogo ?

[cobbaut]

Why bother with Morgan Freeman or Indiegogo for asteroids when there is real information out there.

What are asteroids (90 minutes with a NASA expert):
https://www.youtube.com/watch?...

What can we do against asteroids (again 90 minutes with an expert):
https://www.youtube.com/watch?...

Form your opinion after you see these.

Re:Morgan Freeman? Indiegogo ?

[TheRealHocusLocus]

Why bother with Morgan Freeman or Indiegogo for asteroids when there is real information out there.

[...] What can we do against asteroids (again 90 minutes with an expert):
  [Dr. Stan Love's NEA lecture]

Great informative lecture I hadn't seen before. But why might I decide to feature a link to IndieGoGo campaign and Morgan Freeman instead of headlining it...? Good question.

Well for one thing, the Emergency Asteroid Defence Project and the IndieGoGo campaign represents a group of people who have decided the threat is actionable and has decided on a specific course of action. People in motion -- regardless of skill set -- will always be the greatest arbiters of change. If the mere presence of a good lecture was sufficient to motivate people, it would have had more than 650 views by now. WHEN the Indie campaign hits $200,000 we'll have a newsworthy item to help shape public perception of the danger, and a few lucky folks will have some cool shoulder patches and bumper stickers.

The best part of possessing totems such as these is explaining their purpose to others.

HAIV is an idea that -- once built -- is deployable on any time scale. If they were pre-positioned in orbit or on the Lunar surface they could intercept as soon as humanly possible in a scenario where doing absolutely nothing is worse. To the folks here who pose gentle solutions that would require years to work, that's nice, but your have to ask yourself Where are we getting these extra years from? Some propose interception as 'the object makes its closest (non-impact) pass', that's nice, but which object are we talking about?

I'm talking about the one we'll discover tomorrow that arrives within six months. Or weeks. That is the specific challenge EADP/HAIV is addressing.

One thing bothers me though. About 8 minutes into the lecture he presents an 'average' of 100 persons per year from asteroid deaths (a statistical munging of millennia of zero followed by billions in a day) with the risk from lightning... as if time and percent of human population lost are simple coefficients in some insurance game. I pose not only that these averages are not 'actionable' figures, they are the result the application of statistics in a context where it is absurd (to put it kindly). Besides, his figures are based an extrapolation from the ~10% objects we know about.

The insurance game is a form of the gambler's fallacy, which works both ways. The day before the KT impact there was the same chance of it occurring as the day after. How we assess risk for bad things that could happen has a greater effect on our survival than all the good ones. In learning about this threat and the magnitude of its consequences, you have bitten into the apple. There is no turning back.

Re: Nuclear waste

[Anonymous Coward]

Why don't we let it crash into earth. Won't that cool the climate enough to reverse global warming.

Hit mass with mass

[mrthoughtful]

Don't carry payload into orbit - it's phenomenally expensive. Instead, gather mass that's already up there using lightweight automata. Then accelerate it, and keep it in a parking orbit. Rinse & repeat. The best way to shift mass is with mass. It doesn't really matter what it is. It's also far safer to manipulate mass than it is to manipulate nuclear charges.

The question makes no sense.

[wjcofkc]

Or at the very least only raises more.

1. How big is the asteroid?
2. What is it made of?
3. How fast is it traveling?
4. How far away from the Earth was it when first detected?

I would say we would need to have many different strategies in place based on a mix of those variables.

Re:Nuclear waste

[Livius]

Exactly! Put it on top of a rocket filled with tons of fuel - what could go wrong?

IndieGogo because NASA won't fund this?

[braindrainbahrain]

It seems NASA did fund this concept... for a while, see citation here. Why did they stop this effort? Because of budget priorities? Politics? Or maybe it was a bad idea?

Bruce Willis obviously

[maliqua]

Bruce WIllis and a motley crew of oil riggers

Rush Limbaugh

[jsepeta]

the hot air coming from that gasbag would send the asteroid into a different direction

Re: Nuclear waste

[LifesABeach]

I submit President Bush Jr.; everything he deals with gets fucked up, let him deal with the orbit of an asteroid. God only knows where the thing would go.

Re: Nuclear waste

[Triklyn]

... you don't know me, barrels are scary