Saving Earth from asteroid and comet hits

[neilsox]

Laser may be best as none of the other choices would produce reliable results. A laser beam can fall on the asteroid from thousands of miles away and burn a small hole in the asteroid. The vaporized asteroid material (reaction mass) behaves like a jet engine converting the beam energy to a direction change very efficiently. Admittedly the technology is not there yet, but the other options also need lots of work. Laser on the moon would rarely be in the right place at the right time. We need thousands of at least slightly steerable lasers in solar orbit (through out the inner solar system) to be reasonably certain of diverting an asteroid or comet sufficiently. Any volunteers to live at the mass center of a small asteroid for the next 50 years or so? There is significant probability that we will change a near miss to a hit, instead of the desired out come with any of these methods. By the time we are sure it will hit Kansas City, Missouri instead of Kansas City, Kansas = a bridge apart it is too late for any of these methods.
A 240 meter asteroid will not produce nuclear winter and will only kill a few people if it hits at an average = thinly populated location. A million minor injuries perhaps, and some will likely die a minute sooner than they would have at age 90 or so.
Bigger hits are possible and could produce human extinction or a massive die back. Please tell me where I am wrong. Neil

 

[MeteorWayne]

Sorry, but depending on the size and mass of the asteroid in question, your scenario is unrealistic from a thousand miles away. It's highly unlikely the surface material vaporization would provide suffficient delta V, unless you have some extremely powerful lasers in mind (which don't exist and aren't planned or funded yet), or scores of years to respond.

It's a moot point at the moment, since there are no asteroids with risk within 3 orders of magnitude of the background risk (except for a few with very poorly known orbits)...and in that case (an unkown background asteroid) there wouldn't be time to do more than watch and take the hit.

MW

 

[Floridian]

Laser may be best as none of the other choices would produce reliable results. A laser beam can fall on the asteroid from thousands of miles away and burn a small hole in the asteroid. The vaporized asteroid material (reaction mass) behaves like a jet engine converting the beam energy to a direction change very efficiently. Admittedly the technology is not there yet, but the other options also need lots of work. Laser on the moon would rarely be in the right place at the right time. We need thousands of at least slightly steerable lasers in solar orbit (through out the inner solar system) to be reasonably certain of diverting an asteroid or comet sufficiently. Any volunteers to live at the mass center of a small asteroid for the next 50 years or so? There is significant probability that we will change a near miss to a hit, instead of the desired out come with any of these methods. By the time we are sure it will hit Kansas City, Missouri instead of Kansas City, Kansas = a bridge apart it is too late for any of these methods.
A 240 meter asteroid will not produce nuclear winter and will only kill a few people if it hits at an average = thinly populated location. A million minor injuries perhaps, and some will likely die a minute sooner than they would have at age 90 or so.
Bigger hits are possible and could produce human extinction or a massive die back. Please tell me where I am wrong. Neil

A nuclear pulse rocket could be built with today's technology, using nuclear armament to propel the craft with focused charges "nuclear pulses". It could deliver enough kinetic energy to divert the asteroid, sadly this technology will never be pursued.

 

[a_lost_packet_]

Laser may be best as none of the other choices would produce reliable results. A laser beam can fall on the asteroid from thousands of miles away and burn a small hole in the asteroid. The vaporized asteroid material (reaction mass) behaves like a jet engine converting the beam energy to a direction change very efficiently. Admittedly the technology is not there yet, but the other options also need lots of work.... Please tell me where I am wrong. Neil

It's possible, if the laser was strong and focused enough to vaporize material, that one could divert an asteroid depending upon how far away the asteroid was detected, the dwell time of the laser(s) on the asteroid and the strength. focus of the laser(s) and, most importantly, if the asteroid was of sufficient mass and velocity to cooperate with such a scheme.

"Near Earth Objects" are within an area that extends a little greater than 1 AU from Earth. That's ranges up to and a bit above 92,955,807 miles away...

Ninety two million miles away... A few thousand miles is an approach with a significant "pucker factor" and would not yield enough time for sufficient warning to stop an impactor.

If you had the laser technology, the platforms in the right places, the detection system capable of providing enough warning and asteroids that were handily within the proper limits for your system then, it's possible, it could work. A lot of "ifs" that have to be overcome by technology and chance, IMO.

It's also necessary to note that most asteroids rotate. So, you'd have to have some sort of laser "burst" system set up that did not require a lot of dwell time in one spot in order to accomplish the task. That's a LOT of power. How do we store it for use or provide it for a space-born platform? Lots of tech hurdles to overcome. If we were capable of setting up such a Laser Net, we'd likely have the technology available which could afford us more sure methods.

 

[SteveCNC]

I guess the question is what are our options to deflect or destroy an incoming solid type asteroid .

I can only think of a couple of possible ways to deflect one at least short of any kind of detonation . If you want to change it's course you need some sort of kinetic energy to hit it or a kinetic reaction from the asteroid itself . If the object is spinning which I have no doubt most are it complicates things a little as some energy will be absorbed/changed by the spin depending on where you hit it .

You could try sending in your own asteroid , smaller , more controllable , depending on the angle with which you hit it how much energy you need to achieve the change your after . Not sure about the debris after an impact but I'm sure it would be preferable to a large impact . It has potential .

Maybe if you have time you could create a particle accelerator in space some distance away from earth to give it a better angle to work with (might be doable , less complicated than on earth) and give it a particle stream for a sustained duration to deflect it . Something like a rail gun except much smaller projectiles , a lot longer barrel , and a lot more of them . Of course it has some issues but nothing insurmountable that I can see (this is my pet idea , I would give my ideas on how to construct it but that would derail ) .

Or if you had a satelite array somewhere ~90 degrees to the asteroids line of travel you might could use a trick from the Archimedes story of a death ray and focus light on it for a sustained length of time . The array would no doubt need to be large and probably less doable than the particle accelerator .

Lasers could be the answer , though range might be a problem , I think the effect they would be looking for , similar to the light reflection , would be a kinetic reaction from the surface of the asteroid . As the surface is blown away by the light energy , it causes an opposite reaction from the asteroid . I think I'm describing it right using kinetic energy . if you could actually aim it relative to the spin properly you could even gain a small advantage and decrease the spin , but your angle would again need to be somewhere far away from earth to have a chance of working IMHO . Maybe a moon based laser could have a chance since it could be big enough and reusable more than a satelite type plus the angle would be better than something going around the earth . Or maybe a satelite that drove up close to the asteroid and proceded to bombard it from close range , it wouldn't require as much power to do the same job .

You could try landing on it (alla Armageddon) to either blow it up or mount rockets to attempt to assume control of it . Most likely impossible due to spin or it's just too large to do anything with .

I suppose part of the answer to the problem involves knowing how big is the object in the first place . Would a house sized object present a real problem or do we need only worry about stuff that's much larger . I would think we could assume control over a house sized object without too much problem if we really wanted to .

If you have several orbits before a problem will occur then you have a good angle on it on several occasions . So time is on your side . I guess the biggest problem would be the stray coming in from way out there hitting us the first time thru .

 

[MeteorWayne]

I guess the question is what are our options to deflect or destroy an incoming solid type asteroid .

I can only think of a couple of possible ways to deflect one at least short of any kind of detonation . If you want to change it's course you need some sort of kinetic energy to hit it or a kinetic reaction from the asteroid itself . If the object is spinning which I have no doubt most are it complicates things a little as some energy will be absorbed/changed by the spin depending on where you hit it .

You could try sending in your own asteroid , smaller , more controllable , depending on the angle with which you hit it how much energy you need to achieve the change your after . Not sure about the debris after an impact but I'm sure it would be preferable to a large impact . It has potential .

That may or may not be true, depending on the structural composition of the asteroid and the mass.

Maybe if you have time you could create a particle accelerator in space some distance away from earth to give it a better angle to work with (might be doable , less complicated than on earth) and give it a particle stream for a sustained duration to deflect it . Something like a rail gun except much smaller projectiles , a lot longer barrel , and a lot more of them . Of course it has some issues but nothing insurmountable that I can see (this is my pet idea , I would give my ideas on how to construct it but that would derail ) .

Same problem, it depends on the composition, mass, and earth relative velocity of the asteroid.

Or if you had a satelite array somewhere ~90 degrees to the asteroids line of travel you might could use a trick from the Archimedes story of a death ray and focus light on it for a sustained length of time . The array would no doubt need to be large and probably less doable than the particle accelerator .

Lasers could be the answer , though range might be a problem , I think the effect they would be looking for , similar to the light reflection , would be a kinetic reaction from the surface of the asteroid . As the surface is blown away by the light energy , it causes an opposite reaction from the asteroid . I think I'm describing it right using kinetic energy . if you could actually aim it relative to the spin properly you could even gain a small advantage and decrease the spin , but your angle would again need to be somewhere far away from earth to have a chance of working IMHO . Maybe a moon based laser could have a chance since it could be big enough and reusable more than a satelite type plus the angle would be better than something going around the earth . Or maybe a satelite that drove up close to the asteroid and proceded to bombard it from close range , it wouldn't require as much power to do the same job .

You could try landing on it (alla Armageddon) to either blow it up or mount rockets to attempt to assume control of it . Most likely impossible due to spin or it's just too large to do anything with .

I suppose part of the answer to the problem involves knowing how big is the object in the first place . Would a house sized object present a real problem or do we need only worry about stuff that's much larger . I would think we could assume control over a house sized object without too much problem if we really wanted to .

If you have several orbits before a problem will occur then you have a good angle on it on several occasions . So time is on your side . I guess the biggest problem would be the stray coming in from way out there hitting us the first time thru .

I'd suggest you do a little research on the subject. Search B612, and look elsewhere (including other threads here) where this subject has been discussed in great detail. It isn't as simple as you seem to think, IMHO.

Wayne

 

[SteveCNC]

I was merely trying to go through all the options that might be viable . Just because something is possible , that dosen't mean it's simple , and when talking astronomical scale I highly doubt the word simple would ever be used except in a sarcastic sense . But on the other side of the coin , just because something isn't simple , does that mean it shouldn't be done ? I've never turned away a job just because it was difficult , as long as it was possible , I'd take it on .

I am certain that if we were to attempt to change an asteroids path (planet killer sized) it would be purely on an individual basis and would require plenty of lead time , there's not really much hope of having some net out there keeping us safe from all asteroids/comets at least not any time soon (100 years from now at best maybe more like 300) . And anything that might actually be done for a single asteroid would be several decades away and so this discussion is pretty hypothetical . With the way things are right now there's really no chance of anything happenning soon .

 

[MeteorWayne]

The point I was trying to make is that without knowing the composition of the particular asteroid, any action could make things worse rather than better. Asteroids range from solid iron-nickel cores to agglomerates barely held together by gravity, from rubble piles to fluffballs with the consistancy of what lives under your bed. If you blast one apart it could increase the damage tenfold. If you try and shift the orbit using whatever method, if the mass is wrong by an order of magnitude, you could create an impact when there was no risk before.

It is imperative that you understand the dragon you are fighting

 

[SteveCNC]

It is imperative that you understand the dragon you are fighting

Ahh I guess that's why I clarified on the first line of my post what type of asteroid I was talking about heh

How dangerous would a rubble pile be ? or a fluff pile ?
I don't think impact is the problem since most would burn up on entry , although they might mess up the atmosphere or rain undesirable debris on an area I suppose .

I guess im my mind the one I worry about most is the iron/nickel one . Of all of them it's probably the least trouble to move .

 

[amshak]

We could save Earth from Astroyed in the future , but its difficult save Earth from the commets . Its difficult to save Earth from the huge astroyed , as big as Earth , like the one that crashed into Jupiter . Only a dot could be seen through teliscope , but the Jupiter is big . We have to devolop some other technoloy for these Astroyeds and comets . [ Remember - Life of Dynosors ended because of asteroids ] .

 

[MeteorWayne]

We could save Earth from Astroyed in the future , but its difficult save Earth from the commets . Its difficult to save Earth from the huge astroyed , as big as Earth , like the one that crashed into Jupiter . Only a dot could be seen through teliscope , but the Jupiter is big . We have to devolop some other technoloy for these Astroyeds and comets . [ Remember - Life of Dynosors ended because of asteroids ] .

It was a comet that hit Jupiter (Shoemaker-Levy 9) Many "dots" were seen as the 21 pieces imacted Jupiter's atmosphere.

 

[neilsox]

Probably none of the methods are ready to deploy and all will be extremely costly without major breakthroughs such as the space elevator. The long range laser (or particle beam) has the advantage that it does not disintegrate the asteroid or comet, not even the puff ball type. With near term lasers, less than a second of arc direction change per day may be typical and within range less than a day may be typical, so we need to know the path many years in the future and very precisely, so we can do multiple direction changes which may total enough to assure a miss. The rotation of typical asteroids means we need to stop making the hole typically in three hours as it will no longer be changing the direction in the desired direction. In most cases, the asteroid will pass between 3 lasers (3 dimensions) out of range of all 3 lasers, so we need perhaps a million lasers to average even one with in range per year, briefly. 100 lasers equally spaced in a line 300 million kilometers long, means they are spaced 3 million kilometers apart, in a cube with one million lasers. Worse, they won't be evenly spaced. We can move a laser a million kilometers to get a close shot at an approaching asteroid, but the fuel use will be enormous if we do this frequently. Particle beam is similar to laser, except almost half of the asteroid is the target instead of a tiny spot. I believe, however, that particle beams diverge faster than laser beams, so the typical range may be no better. How does the cost compare? Neil

 

[amshak]

We cannot Save Earth From Comets . Its verry Difficult . I cannot Say About Future . We may be able to destroy some Astroyeds From Inside . Programming Space shuttle to go Astroyed , Dig and Blast Some Nuclear Atomic Bomb from Inside.

 

[MeteorWayne]

The space shuttle can only go to low earth orbit, and there are only two flights left before the program is shut down.

 

[amshak]

Ok , So some other kind of other technology , all controled from Earth And to land on Astroid

 

[a_lost_packet_]

The point I was trying to make is that without knowing the composition of the particular asteroid, any action could make things worse rather than better. Asteroids range from solid iron-nickel cores to agglomerates barely held together by gravity, from rubble piles to fluffballs with the consistancy of what lives under your bed.

I've seen some of the things that live under my bed. They're not to be trifled with! As it is, I have to pay strict attention to a particularly nagging, unidentified bit of possibly sentient material that demands socks as Sacrificial Gifts. I haven't yet figured out how to take that as a write-off on my taxes.

If you blast one apart it could increase the damage tenfold. If you try and shift the orbit using whatever method, if the mass is wrong by an order of magnitude, you could create an impact when there was no risk before.

Absolutely. The method used to counteract the danger of a possible impactor is going to be highly dependent upon the impactor itself. We don't have the luxury or technology to develop a "Single Method" solution for earth impactors just yet. Perhaps, one day, when we have space tugs and interplanetary battleships, we can simply move them out of the way or blast them into space dust. But, that isn't today.

It is imperative that you understand the dragon you are fighting

Nifty quote. I'm gonna steal that one from you.

 

[a_lost_packet_]

It is imperative that you understand the dragon you are fighting

Ahh I guess that's why I clarified on the first line of my post what type of asteroid I was talking about heh

How dangerous would a rubble pile be ? or a fluff pile ?
I don't think impact is the problem since most would burn up on entry , although they might mess up the atmosphere or rain undesirable debris on an area I suppose .

I guess im my mind the one I worry about most is the iron/nickel one . Of all of them it's probably the least trouble to move .

Ever been in a snowball fight? You know the rule - No rocky snowballs. Well, unfortunately, that might be the consistency of some asteroids - A powdery conglomeration of rocks.

In regards to loosely held together asteroids, they would still be a major concern. Sure, a big solid rock is a problem. But, so is a bunch of smaller rocks. Ever been hit with a rock or a handful of gravel? You know the difference. But, does the Earth and, more importantly, would we? Not really. We're sort of in a closed system that can't take a lot of added energy without extreme consequences.

What's so destructive about an asteroid impact? Well, aside from whatever was under it when it hit, the whole area is going to be subject to that immediate release of energy. Some of that will be expended in producing great debris clouds. Some of it will go into generating heat which is going to ignite everything in the surrounding area. A bit more will go into irritating the Earth but, the Earth's a big boy and won't care overmuch unless it's a particularly big rock.

What's really destructive that we are going to care about are the after-effects of the impact, not the impact itself. A great deal of energy is going to be released. In a single impactor, that is going to occur in one spot. But, in the case of multiple impactors, that is going to occur over a possibly wide area. Debris are still going to be thrown up into the atmosphere. Heat is still going to be generated from the impact. Basically, we're talking about localized, massive damage spreading destruction over a large area versus widely scattered, slightly less immediate damage but effecting a very wide area. Neither is desirable at all and both have the potential of effecting our climate worldwide. Because of the after effects, a handful of gravel could cause just as many problems, or even more, than a single impactor. It's all going to be dependent on how much energy we're subjected to at the time.

Interesting tidbit - Depending upon their size and composition, individual meteorites can actually be cold to the touch if you're lucky enough to pick them up very soon after they arrive. Sublimation of surface material as it courses through the atmosphere quickly bleeds off the heat that would be generated. Picked that up in some book I was reading awhile ago.

 

[MeteorWayne]

Two points. The damage from an asteroid comes from the kinetic energy. The formula for that is 1/2 mass times velocity squared.( 1/2m*v^2)
It really doesn't matter if the mass is one solid chunk, mostly ice, or 50 broken up bits, the energy dumped into the atmosphere and earth is the same.
Also note that it is very sensitive to the velocity of the impactor. For two objects of the same mass, if one hits at twice the speed, 4 times as much energy is released.
The minimum impact speed is set by the earth's gravity, so it about 11.2 km/s.
Scanning the current list of risky NEAs on the JPL Sentry page, the Vinf (velocity before accounting for the earth's gravity) ranges from 0.93 km/sec to 39.47 km/sec. After accounting for gravity, the atmospheric impact speed would be 11.24 and 41.03 km/s respectively. So for an object of the same mass, the faster one would have 13.4 times as much energy.
That is also what makes comet impacts potentially so deadly; they can hit at speeds up to 72 km/sec like the Leonid (fortunately very tiny) meteors, since they can come from any direction, even hitting earth head on. An object of the same mass would have 41 times the energy of the slower one above.

Second, in fact almost all meteorites are cold. As a_l_p said, anything that melts on the surface is swept away by the airflow removing the heat, and secondly most meteorites spend many minutes falling through the air nearly straight down after they lose their cosmic velocity, so the surface has plenty of time to cool. And it's cold in space, so it starts out very cold

MW

 

[SteveCNC]

I always thought that a small meteor would burn completely up trying to enter our atmosphere due to the large amout of surface area vs mass . It seems like there would be a minimum size to even reach the ground , not sure what that size would be though . That's why I would question a cloud of looses rocks even making it to the surface . Unless instead of rocks they were boulders .

 

[MeteorWayne]

Even if smaller pieces burn up in the atmosphere, the energy dumped is the same whether in 50 pieces or one.

It all comes down to the mass and velocity of the starting object.

MW

 

[amshak]

I think we could blast some of the medium sized Astroyed with some Atomic misile or something . Or we could Blast it from the inside . But do you have have any idea about destroying the Commet ? I think we could melt it with some lasors and then blast it up [Sorry if it sounds silly]

 

[MeteorWayne]

Actually, everything you've proposed so far is silly, so there's no point in apologizing.

 

[Couerl]

It all comes down to the mass and velocity of the starting object.

MW

Right, if she's a planet killer about 20km or bigger and more or less solid rock we're done no matter what. Smaller things 1-5km might succumb to a form of JDam or bunker buster nuke if we could develop them in time, lots and lots of them. True that the shotgun effect carries just as much net energy, but I'd take my chances with the broken down version over the big one and if it's a sure thing we have nothing to lose trying anyway. I'd say we should go down slugging.

 

[amshak]

Diverting the way may be the answer .
French, a doctoral candidate in aerospace engineering at North Carolina State University, has determined a way to effectively divert asteroids and other threatening objects from impacting Earth by attaching a long tether and ballast to the incoming object. By attaching the ballast, French explains, "you change the object's center of mass, effectively changing the object's orbit and allowing it to pass by the Earth, rather than impacting it."
Sound far-fetched? NASA's Near Earth Object Program has identified more than 1,000 "potentially hazardous asteroids" and they are finding more all the time. "While none of these objects is currently projected to hit Earth in the near future, slight changes in the orbits of these bodies, which could be caused by the gravitational pull of other objects, push from the solar wind, or some other effect could cause an intersection," French explains.

 

[a_lost_packet_]

Diverting the way may be the answer .
French, a doctoral candidate in aerospace engineering at North Carolina State University, has determined a way to effectively divert asteroids and other threatening objects from impacting Earth by attaching a long tether and ballast to the incoming object. By attaching the ballast, French explains, "you change the object's center of mass, effectively changing the object's orbit and allowing it to pass by the Earth, rather than impacting it."
Sound far-fetched? NASA's Near Earth Object Program has identified more than 1,000 "potentially hazardous asteroids" and they are finding more all the time. "While none of these objects is currently projected to hit Earth in the near future, slight changes in the orbits of these bodies, which could be caused by the gravitational pull of other objects, push from the solar wind, or some other effect could cause an intersection," French explains.

Or, if you had that kind of time and the means to loft such ballast, you wouldn't need to attach it at all. Just maneuver the ship next to the asteroid and let gravity do the rest. No tether is required as some sort of connection to another mass. I'd have to see his proposal to comment further on it. But, judging by the description that has been given he had better finish up his aerospace engineering coursework.