Can current ballistic missiles target asteroids?

[willpittenger]

There was a Charlton Heston movie where an incoming asteroid in the 10-km or larger class is broken up by space born nuclear missiles that the US and Soviets put in space covertly. In the movie, the missiles were aimed directly at the asteroid. That was stupid as it merely broke the asteroid up. They still had several large chunks coming in. Most hit New York City.<br /><br />But suppose the missiles were aimed for near misses. Would the missiles have enough oomph to reach the asteroid in time? (We do not have the orbital platforms in the movie. So each missile much reach space with the same fuel needed to reach the asteroid.) Would their explosions be strong enough to put the asteroid on a new orbit that is safer given their limited range? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[gunsandrockets]

Short answer: No.<br /><br />Long answer: A 10 km size asteroid is enormous. Any reasonable chance using any non-magical means of deflection would require changing the course of the asteroid years before the time of impact, maybe even decades before impact.

 

[vogon13]

Throw weights of current missles are designed with potential targets on the earth's surface in mind.<br /><br />There would be no trajectory possible to any asteroid (unless it was imminenetly to collide with earth) that any missle would have sufficient delta-v to reach.<br /><br />Additionally, the on board guidance systems of the missles are designed to very accurately hit specific points on the earth's surface (neglecting high altitude EMP effect shots). Even minute variations in the gravity model of earth are programmed in, along with detailed models of the earth's atmosphere for re-entry effects.<br /><br />Such a guidance system is not designed to guide a missle to an asteroid, or near one.<br /><br /><br />If we had time, a missle could be modified for your mission. Unloading all but one of the warheads, adding an upper stage for more delta-v, and adding a more capable guidance system (like the one on Deep Impact).<br /><br />Nuclear effects on an asteroid are hard to predict without a practice shot, or two.<br /><br />A solid rigid object would experience reaction forces from spalling effects of a close nuclear detonation. This could, if delivered soon enough, deflect the asteroid enough.<br /><br />Additionally, a penetrating warhead would, if detonated at an optimum depth, blow off a great deal of overlying asteroidal crust. Again, reaction forces must be great enough in the time available to deflect the asteroid.<br /><br />If caught soon enough, an asteroid on a collision course with earth could be deflected with something as innocuous as a can of paint.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[mlorrey]

Most calculations critical of a nukes ability to destroy or deflect an asteroid assume such is going to be a solid rock or hunk of iron/metals. This view is not supported by recent explorations, which indicate that most asteroids, at least, are loose agglomerations of smaller bodies, rocks, dust, and even volatiles. Given this, modern nuclear warheads, even without the advantages of atmospheric tamping effects that make them so effective on earth's surface, should be able to shatter most asteroids into many smaller bodies.<br /><br />Doing so is not really a bad thing, it breaks the target up mostly into pieces that will either burn up on entry to earths atmosphere, or land without doing significant damage, particularly without causing deep impact craters that would trigger lava extrusions and massive dust envelopes of earth's entire atmosphere, or wind up trapped in orbit around the earth, where they would become useful raw materials for orbital construction (though the risk of depressurization from sand and pebbles would be increased for some time after).<br /><br />Particularly with the new nukes that Bush has directed the DoE to develop that are capable of significant ground penetrations before detonation. This capability would amplify the ability of the nuke to shatter the asteroid from within.

 

[willpittenger]

Breaking the asteroid up is generally NOT considered desirable. Even as dust, it would still heat the atmosphere up. In Arthur C. Clarke's book <i>Hammer of God</i>, a piece just skims the southern part of Earth's atmosphere. That melted the polar ice cap flooding New York City and Florida.<br /><br />The one good thing that I can think of for the break up is that because the debris is spread out, more of it would miss. Trouble is, because the debris is spread out, the overall likelihood that something would hit Earth goes up. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[mlorrey]

SF geek alert! "Hammer of God" is fiction, for a very good reason. An asteroid passing through the upper atmosphere over the pole will not in any way cause its ice cap to melt.<br /><br />As an alternative to one big species exterminating impact, I would say that lots of little impacts are far more desirable: most all would be so small that they would produce no mushroom cloud effects that would put dust in the upper atmosphere. Furthermore, dust entering the atmosphere at high speed may heat it up, but dust lofted into the atmosphere by impacts, and dust hanging in the atmosphere after entry, cools it. The two effects will balance out.

 

[tomnackid]

Where the hell did you get this info from??? A billion tons of dust hitting the Earth all at once at orbital speeds is still a bad thing, probably worse than one single piece. Comet Shoemaker-Levy had a mean density lower than whipped cream and it was torn to pieces before hitting Jupiter yet it still managed to punch Earth-sized holes in the upper atmosphere. Stop pulling wild-ass ideas out of your butt and presenting them as "fact".

 

[chriscdc]

Umm no, The heating of the atmosphere would kill substantial number of animals on the ground. That russian asteroid, almost a century ago, was only a few metres across and exploded miles up, it still flattened hundreds of square miles. Now imagine millions of such rocks, from a broken up asteroid, all falling within a few thousand km of each other.

 

[drwayne]

But that was a blast effect, was it not?<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[baktothemoon]

Ok, so we have nukes powerful enough to destroy the asteroid, how do we get them there in time? Normally we have to find the asteroid years in advance, but in case we didn't we wouldn't have time to put nukes on a special probe and send them to the asteroid. I say that we should put some smaller nuclear missiles on the moon and maybe have an orbiting station out at L3. This way we could still fire the rockets if the asteroid was only a few weeks from hitting Earth. Now I know already that the treaty that we signed with the UN prohibited putting weapons on the moon. One, I believe that the UN has no authority to say what happens to the moon since the UN is on EARTH and shouldn't have jurisdiction over every object in the solar system and the UN has not sent people to the moon and does not have the capability to do so. That and the nukes would be to protect the world, not just us. So I think we should still put some nukes on the moon to protect ourselves and the world.<br /><br /> "Ask not what your country can do for you, ask what you can do for your country."John F. Kennedy

 

[spacefire]

the cumulative effect of all available nukes might be enough to deflect the asteroid. remember most likely the path of the asteroid would be close to tangent to Earth's, though obviously gravity would come into play and make it curve toward the planet.<br />that being said, continuously detonating nukes Earthside during the final portion of the asteroid's trajectry might<br />change its path just enough to miss us.<br />It depends how early this bombarment can be started, that is, how high ICBMs can get. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[tomnackid]

OK, imagine reducing Mt. Everest to gravel and spreading it over an area as wide as the surface of the Earth--all within a matter of days or weeks. That is what we are talking about here. I don't think the world's entire nuclear arsenal could do it. If the asteroid is a loose conglomeration as some are the problem is even worse. It would be like punching a pillow. Remember outside of the atmosphere nukes don't produce much of a shockwave. All of those dramatic movies of building being blown apart and forests being leveled by bomb tests are showing the effects of the blast wave of displaced air. In a vacuum those houses and trees would mearly be singed.<br /><br />Energy is energy. A certain mass moving at a certain velocity has a certain amount of energy. It doesn't matter if the mass is in one piece of a million its still the same amount of energy. The atmosphere will still have to absorb it. We are fooled into thinking that smaller pieces are better because we are used to smaller pieces of matter hitting the Earth spread out over a long period of time, but if they all come at once.... If you could somehow break up the asteroid in a way that spreads out the impact over a long period of time then you could lessen the damage.

 

[john_316]

<b>"Additionally, the on board guidance systems of the missles are designed to very accurately hit specific points on the earth's surface (neglecting high altitude EMP effect shots). Even minute variations in the gravity model of earth are programmed in, along with detailed models of the earth's atmosphere for re-entry effects."</b><br /><br />I feel that most guidance systems of America's arsenals have capable IMU's to accurately target an incoming asteroid or comet especially with lead time of a year or several years.<br /><br />The Inertial Measurment Units on some modern Missiles actually shoot the stars prior to the release of the MIRVs from the Apple Cart over designated targets.<br /><br />So IMU's and GNCU's can be reprogrammed or whatever. If you wish to use a second stage you can add that with some modification. You can also load most of those same MIRVS on Solids or Chemical rockets such as Atlas or Delta if need be.<br /><br /><img src="/images/icons/smile.gif" /><br />

 

[mlorrey]

Nukes don't produce much of a shock wave in vacuum. They will produce a heck of a shock wave in rock, ice, or dust balls, especially IF the explosion occurs within the object. Admittedly a surface detonation would mostly reflect the force into space, though most people who have done the calculations assume asteroids are solid rock and/or metal from the surface downward. However a subsurface detonation would transmit all of the energy as shock waves through the material of the asteroid. If the asteroid is a gravel/dust ball, a normal MIRV should have no problem penetrating such a thing to significant depth before detonation.<br /><br />As for the impact of lots of little pieces: Assume a 1 km radius asteroid that is an agglomerate. It gets pulverized as it passes GEO by one of George Bush's ground penetrating bunker-busting nukes penetrating 200 meters into the asteroid before detonation, and blasts it into a whole range of pieces:<br />5 x 100m dia<br />50 x 50 m dia<br />200 x 10 m dia<br />1000 x 1 m dia<br />10,000 x 100 cm dia<br />1,000,000 x 10 cm dia<br />100,000,000 x 1 cm dia<br />1,000,000,000,000 x 10 mm dia<br />100,000,000,000,000 x 1 mm dia<br />1 x 10^13 grains of micron size or smaller.<br /><br />As we've dealt with the tamping issue by making our nuke a ground penetrator, as is allegedly the type currently under development by the DoE for the "war on terrorism", we are able to assume that the material is blasted away at the initial velocity of material near ground zero of a nuclear blast. If we assume a Hiroshima-level bomb, 15 kt, the energy output is 6.3 × 10^13 joules = 63 TJ (terajoules).<br /><br />Thus, we need to use underground shock effects to measure the result of a ground penetrating nuke on an asteroid, NOT the known minimal effects of a nuke going off in empty space.<br /><br />This site is pretty good:<br />http://www.fas.org/faspir/2001/v54n1/weapons.htm<br /><br />Showing tha

 

[scottb50]

Did the Japanese see a lot of effect on Hayabusa? I haven't seen much about it for a while.<br /><br />I would also think the seemingly random shapes of objects would be pretty hard to target. I agree that an impact would have serious short term effects, long term effects would be pretty local. Unless it was very big, then we would be out of luck anyway right now anyway.<br /><br />Luckily we would probably know about something that big already. The problem is, at some points, it has to happen in a major location, statistics say so and human sprawl keeps lowering the unoccupied areas. From what I see the number of huge craters is not very large. That would indicate we are pretty safe, at least until the debris that didn't become Mars gets here. <div class="Discussion_UserSignature"> </div>

 

[willpittenger]

And build the launch platforms in the movie? Could you build them so the missiles could not be targeted at Earth by some crazed dictator? If so, you could have them in an orbit outside Lunar Orbit waiting to be called on. Perhaps the Earth/Sun L4/L5 points like what SOHO uses.<br /><br />I should note the movie goofs. It has the missiles thrusting until they go up. There is no cruise stage. Nor do you see steering thrusters fire. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

Arthur C. Clarke's book <i>The Hammer of God</i> featured a gigaton warhead. How much bigger is that than anything built or theorized? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

<blockquote><font class="small">In reply to:</font><hr /><p>If the asteroid is a loose conglomeration as some are the problem is even worse. It would be like punching a pillow. Remember outside of the atmosphere nukes don't produce much of a shockwave.<p><hr /></p></p></blockquote><br />But they produce a big radiation surge. That would hit the asteroid real hard. So I think you should stand the weapon off and have it explode 1 km away.<br /><br />As for your trees, they would be cooked -- not singed. Any human exposed would start having funny looking kids if he or she did not die from that radiation first. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[drwayne]

The highest yield I recall seeing reported in the press was on the order of 100 - 200 Megatons.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[chriscdc]

Well yes it was the blast, but a blast caused by the heating of the asteroid due to the atmosphere, unless asteroids are a surprise source of TNT that is.

 

[drwayne]

I understand the concept of the object being heated by the atmosphere.<br /><br />An earlier post seemed to refer to significant heating of the atmosphere by the object(s). I did not see the latter as the effect that led to the destruction, that was why I was asking.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[meteo]

Exactly, a 1 mile asteroid broken into pieces before hitting the earth still has the same kinetic energy. That energy is still going to be absorbed by something. <br /><br />1 mile diameter - 17 km/s - Pourous Rock (Asteroid)<br /><br />4.73 * 10^20 Joules<br /><br />Earth's atmosphere has a mass of 5 * 10^18 kg, 1*10^18 kg will be the area effected in this very dispersed dust cloud impact. Assuming dry air R=287.05 J/(kg*K), 1/5 of the mass of the atmosphere will be heated 1.65 K, so the atmosphere may be able to absorb a 1 mile asteroid pulverized into dust by a giant nuke.<br /><br /><br />5 mile diameter - 51 km/s - Ice (Comet)<br /><br />KE = 3.53 *10^23 J<br /><br />Atmosphere will be heated 1229.75 K.<br /><br />So using these very rough calculations some impacts can be absorbed by the atmosphere if spread out and others would scorch the entire planet.<br /><br />http://www.lpl.arizona.edu/impacteffects/<br />

 

[tomnackid]

Niven and Pournelle devote a chapter of "Lucifers Hammer" to explaining how a comet that is "nothing but dust and ice particles" less dense than whipped cream could possibly cause any harm to Earth.

 

[mlorrey]

Your calculations avoid the fact that most of this energy escapes to space. All of the heating that occurs above the ozone layer and CO2 concentrations will be reflected back to space.

 

[chriscdc]

Any links to support this claim?