How Can We Effectively Destroy An Asteroid Headed for Earth?

[baywax]

The mission to destroy the failing US spy satellite was a total success according to Pentagon officials.

http://news.yahoo.com/s/ap/20080221/ap_on_go_ca_st_pe/dead_satellite

 

[carstensentyl]

(A moderate asteroid is between a thousand and a million Gigatons. Does that put it in perspective?)

That is far more than the combined mining blast fragmentation on the planet. That's a special thing to consider when nuclear warheads are occassionally used to fragment bedrock for mining operations.

If a giant meteor is headed, we had better divert it (can our weapons even nudge it in another direction?) because we stand no chance of destroying most meteors, when our mining can't even tickle the thin crust of the planet we live on.

 

[James Essig]

Hi carstensentyl;

Thanks for the feedback.

Note that there is no limit to the size of a thermonuclear warhead theoretically.

A thermonuclear warhead with a mass of 10 EXP 15 metric tons or a with diameter of 100 kilometers would produce enough blast, ionizing radiation, and thermal energy, in short its energy yield, to completely vaporize 50 planets with the mass of the Earth that were frozen to the core considering the heat capacity, latent heat of fusion, and latent heat of vaporization of the materials out of which Earth is composed.

A thermonuclear warhead with the mass of the Earth could completely vaporize 100 million such planets.

A artificially produced white dwarf massed thermonuclear warhead could completely vaporize (150,000)(100,000,000) or 15 trillion planets with the mass of the Earth.

A larger thermonuclear device involves another more far out idea to gradually construct a huge white dwarf densitied thermonuclear device with the mass of about 10 EXP 6 solar masses wherein the finished product would be a rotating toriod with a diameter of about 6billion kilometers. The device could be gradually spun up until it reached the end of construction and a rotation velocity on the order of several hundred kilometers/second would prevent it from undergoing gravitational collapse before detonation. White dwarf dense toriodal material would allow for a thin aspect ratio toriod to reduce gravitational/rotational induced tidal forces which otherwise could tear the ring apart. A rotational velocity of say 500 km/second would permit the fusion energy yield to be efficiently stored at about 5,000 times greater than that of the rotational kinetic energy.

This baby would have a yield of 1,000,000 carbon detonation supernova and could completely vaporize 15 million trillion such planets or 15 x 10 EXP 18 such planets.

A still larger version of a ring 600 billion kilometers in diameter would have a yield of 100,000,000 carbon detonation supernova and would produce enough yield energy to completely vaporize 1.5 x 10 EXP 21 such planets. If one out of every 30 stars in our observable universe has a planet like Earth orbiting it, the number of all of such planets in the observable universe with the mass of the Earth would be about 1.5 x 10 EXP 21.

Using matter/antimatter toroidal configurations or concentric matter and antimatter toruses made of nuetron dense forms of matter and antimatter such as solid neutronium and antineutronium, devices with a mass of 10 EXP 14 solar masses with a sub black hole enclosed volume density and a radius of 20 lightyears would produce enough energy upon matter antimatter annihilation completely vaporize 1.5 x 10 EXP 29 planets with the mass of the Earth frozen to the core. This is equivalent to the entire baryonic mass within the observable universe. However, such a device would be ridiculous to construct because it would produce a great enough hard gamma ray flux to potentially kill of all extraterrestrial civilizations within the observable universe with a current radius of 13.7 billion lightyears. However, given a billion years of ever increasing human population within the universe and growth of our space based materials production and manufacturing infrastructure, we could probably build such a device.

I can think of possibly even much larger yield thermonuclear and matter antimatter devices composed of a layered arrangement of fusion or matter antimatter fuels and an exotic theoretical material known as negative mass which has yet to be discovered let alone produced. With judicious layering of fuels and negative mass in an onion like arrangement, in theory devices with infinite mass and infinite yield could be constructed given an infinite amount of time to construct them. If the life time of protons turns out to be finite, one could simply use eternally stable forms of quarkonium, a theoretical material with a density as great as 1,000 times that of the atomic nucleus in the construction of the cosmic onion.

In short, there really is no theoretical limit to the size and yield of the devices we can construct.

On the lighter side, a pure fusion thermonuclear device with the mass of a modern nuclear powered aircraft carrier would have a diameter of only about 200 feet and yet could completely vaporize an asteroid with the mass of (1/2)(100,000)(200,000,000) metric tons or 10 trillion tons. A cubic mile pure fusion device with an average density of water could completely vaporize a (1/2)(1,000,000,000)(200,000,000) metric ton asteroid or an asteroid with a diameter of 425 kilometers.

Note that if efficient mass drivers in the form of electromagnetic guns can be developed to launch payload after payload into Earth orbit, there is no reason why a highly efficient billion ton fission fusion fusion nuke could not be assembled in low Earth orbit in 10 to 20 years and used to attack any asteroid conceivable given enough lead time. Huge chemical rockets could set the nuke on course to ablissimate any conceivable asteroid.

Regards;

Jim

 

[baywax]

In short, there really is no theoretical limit to the size and yield of the devices we can construct.

On the lighter side, a pure fusion thermonuclear device with the mass of a modern nuclear powered aircraft carrier would have a diameter of only about 200 feet and yet could completely vaporize an asteroid with the mass of (1/2)(100,000)(200,000,000) metric tons or 10 trillion tons. A cubic mile pure fusion device with an average density of water could completely vaporize a (1/2)(1,000,000,000)(200,000,000) metric ton asteroid or an asteroid with a diameter of 425 kilometers.

Note that if efficient mass drivers in the form of electromagnetic guns can be developed to launch payload after payload into Earth orbit, there is no reason why a highly efficient billion ton fission fusion fusion nuke could not be assembled in low Earth orbit in 10 to 20 years and used to attack any asteroid conceivable given enough lead time. Huge chemical rockets could set the nuke on course to ablissimate any conceivable asteroid.

Regards;

Jim

Is there a record of what happens when you detonate a nuke in space?

 

[carstensentyl]

Baywax. I think nukes are actually stronger in space, but I could be mistaken since I know nothing about nuclear fission.

Jame's post has some very interesting pointers about how much destruction a nuclear weapon can cause. However, I do not agree that we will have the technology to send anything larger than a conventional space shuttle into space any time soon. I suppose that the parts could be assembled in space.

Do we have a means of detonating a large nuclear device? Isn't there some limit to the amount that we are capable of detonating?

 

[DaveC426913]

Baywax. I think nukes are actually stronger in space, but I could be mistaken since I know nothing about nuclear fission.

I doubt it. Much of the destruction is due to the pressure wave that is transmitted through the air. In space, all you'd get is the primary shock, which is limited tot he mas of the bomb itself.

Do we have a means of detonating a large nuclear device? Isn't there some limit to the amount that we are capable of detonating?

Well, since we don't have the means to build one, I'm not sure how we don't have the means to detonate one...


However, it is a chain reaction, so there's no reason why it should be particularly difficult.

 

[Astronuc]

Dave is correct. The detonation of a nuclear device has to do with it's architecture, not the environment surrounding it.

A large nuclear device would be thermonuclear in which the fusion assembly is triggered with a fission device (trigger). In the case of a satellite it would be overkill.

In the case of an asteroid, the objective would be to get the warhead as close as possible to the asteroid (and possibly in contact or shallow penetration). The nuclear explosion would be used to rapidly heat (via radiation) one side of the asteroid and use the effect of ablation to deflect the asteroid.

The approach may be dependent on the composition of the asteroid, e.g. ice vs stoney/metal.

 

[baywax]

Dave is correct. The detonation of a nuclear device has to do with it's architecture, not the environment surrounding it.

A large nuclear device would be thermonuclear in which the fusion assembly is triggered with a fission device (trigger). In the case of a satellite it would be overkill.

In the case of an asteroid, the objective would be to get the warhead as close as possible to the asteroid (and possibly in contact or shallow penetration). The nuclear explosion would be used to rapidly heat (via radiation) one side of the asteroid and use the effect of ablation to deflect the asteroid.

The approach may be dependent on the composition of the asteroid, e.g. ice vs stoney/metal.

So, because there is no atmosphere to transfer a lot of the energy from the blast to the object (in space) the device is going to work better if its embedded in the material. Like one of the bunker buster-type shells with a delayed detonation time?

 

[carstensentyl]

There has got to be some sort of limit to the size of the explosion. Jam-packing more material into the bomb just doesn't seem to do it for me. There must be a maximum detonation velocity. Of course, we can always create a bigger explosion with multiple warheads...

 

[Astronuc]

So, because there is no atmosphere to transfer a lot of the energy from the blast to the object (in space) the device is going to work better if its embedded in the material. Like one of the bunker buster-type shells with a delayed detonation time?

Nuclear weapons produce a tremendous quantity of radiation in a broad spectrum, not only in gamma and X-ray, as would be expected in a nuclear explosion, but also in UV, visible and infrared. Many people in Hiroshima and Nagasaki received burns from the bright light, as well as receiving UV, X-ray and gamma radiation which penetrated the skin and body according to energy level.

If a nuclear warhead is detonated near an asteroid, it would receive a burst of radiation which would heat some volume and cause some material to ablate.

If the warhead impacted, then detonated, then there would be some explosive removal of the asteroid material.

There has got to be some sort of limit to the size of the explosion.

Yes, there is an optimal yield-size relationship, but that details would not be discussed in a public forum.

 

[James Essig]

Hi Folks;

One obviously mathematically proveable way to be able to assemble a 10 EXP 15 metric ton warhead with a yield energy sufficient to vaporize perhaps as much as 100 planets with the mass of the Earth is simply to gradually assemble a cubic or spherical arrangement of 10 EXP 15 one metric ton almost pure fusion devices, wherein each device could have a max yield of 2 Gigatons. If a 1/2 meter space was required between each device in order for the devices not to be destroyed during the chemical explosive initiation phase, that would be fine. The nuclear devices could be set off simultaneously enough with current high tech timed initiators such that they would all go off within 10 nanoseconds of each other. Such a device might even be able to create a macroscopic massed but microscopically spatially tiny black hole in the center due to the compounded enourmous radiation and plasma induced pressure at the center of the device. The only theoretical limit to such a device is that of the number of aggregated warheads that would lead to gravitational crushing of the structure and premature destruction of the component bomb units.

What's more, the airforce is now alledgedly working to develope pure antimatter weapons. Stable forms of uncharged antimatter are rumored to have been produced in small qauntities such as positronium atoms, a bound state of a positron and an electron wherein the distance between these bound particles is great enough to prevent Fermi-Dirac pair annihilation. A macroscopic quantity of positronium would be induced to explosively react by some form of purturbation which would propagate through the material at a velocity near or equal to light speed in a chain-reaction.

Antimatter hydrogen has been produced in very small quantities at CERN and other accelerator labs and offers an excellent way to store antimatter in relatively dense but neutral form thus also permitting huge aggreagations of antimatter to be stored without worrying about coulombic repulsive forces.

A one metric ton of matter/antimatter composite fuel or one half a metric ton of antimatter depositied within an asteriod with a mass of 10 gigatons could in theory completely vaporize the asteriod. A 10 EXP 15 metric ton aggregate of antimatter could in theory completely vaporize 10,000 planets with the mass of the Earth.

Other conjectured devices that would dwarf the mass/specific yield of nuclear weapons are so-called quark bombs that would release the energy contained within the quarks comprising hydrogen somehow for stupendous mass specific yeilds. In short, a quark bomb would be simply a much more advanced form of nuclear device. If some way of manipulating hydrogen nuclei or protons can be found in accordance within the bounds of, or in loop holes in, quantum-chromo-dynamics or qcd, the strong force gluon/quark analogue to quantum-electro-dynamics or qcd, we might be able to produce a weapon so powerful that it would simply be too dangerous to be publically revealed at least as to the general working principles of such a device.

Yet another exotic speculative device is referred as the Boson Bomb and this device presumably would some how allow energy production and release utilizing the Higg's Boson(s) which according to the Standard Model of particle and fields is the quanta of the all pervading field which is responsible for embueing massive particles with mass or the cause of inertial mass in bodies with mass. The search for the Higg's Boson will continue when the updraded Light Hadron Collider or LHC goes on line at the European CERN facility in a few weeks. Tantalizing evidence for the existence of the Higg's Boson was alledgedly obtained several years ago although the possible observations were so few so as not to be statistically significant. The approximate lower mass equivalence limit of the Higg's Boson is I believe to be about 190 GeV at a 95 percent confidence level.

Therefore, I strongly feel that we definitely have the explosive means for dealing with large rouge asteriods given enough lead time and human ingenuity.

Regards;

Jim Essig

 

[Astronuc]

One obviously mathematically proveable way to be able to assemble a 10 EXP 15 metric ton warhead with a yield energy sufficient to vaporize perhaps as much as 100 planets with the mass of the Earth is simply to gradually assemble a cubic or spherical arrangement of 10 EXP 15 one metric ton almost pure fusion devices, wherein each device could have a max yield of 2 Gigatons.

Um, NO! It's not mathematically provable.

What's more, the airforce is now alledgedly working to develope pure antimatter weapons. Stable forms of uncharged antimatter are rumored to have been produced in small qauntities such as positronium atoms, a bound state of a positron and an electron wherein the distance between these bound particles is great enough to prevent Fermi-Dirac pair annihilation. A macroscopic quantity of positronium would be induced to explosively react by some form of purturbation which would propagate through the material at a velocity near or equal to light speed in a chain-reaction.

Antimatter hydrogen has been produced in very small quantities at CERN and other accelerator labs and offers an excellent way to store antimatter in relatively dense but neutral form thus also permitting huge aggreagations of antimatter to be stored without worrying about coulombic repulsive forces.

A one metric ton of matter/antimatter composite fuel or one half a metric ton of antimatter depositied within an asteriod with a mass of 10 gigatons could in theory completely vaporize the asteriod. A 10 EXP 15 metric ton aggregate of antimatter could in theory completely vaporize 10,000 planets with the mass of the Earth.

Other conjectured devices that would dwarf the mass/specific yield of nuclear weapons are so-called quark bombs that would release the energy contained within the quarks comprising hydrogen somehow for stupendous mass specific yeilds. In short, a quark bomb would be simply a much more advanced form of nuclear device. If some way of manipulating hydrogen nuclei or protons can be found in accordance within the bounds of, or in loop holes in, quantum-chromo-dynamics or qcd, the strong force gluon/quark analogue to quantum-electro-dynamics or qcd, we might be able to produce a weapon so powerful that it would simply be too dangerous to be publically revealed at least as to the general working principles of such a device.

Yet another exotic speculative device is referred as the Boson Bomb and this device presumably would some how allow energy production and release utilizing the Higg's Boson(s) which according to the Standard Model of particle and fields is the quanta of the all pervading field which is responsible for embueing massive particles with mass or the cause of inertial mass in bodies with mass. The search for the Higg's Boson will continue when the updraded Light Hadron Collider or LHC goes on line at the European CERN facility in a few weeks. Tantalizing evidence for the existence of the Higg's Boson was alledgedly obtained several years ago although the possible observations were so few so as not to be statistically significant. The approximate lower mass equivalence limit of the Higg's Boson is I believe to be about 190 GeV at a 95 percent confidence level.

Therefore, I strongly feel that we definitely have the explosive means for dealing with large rouge asteriods given enough lead time and human ingenuity.

Please refrain from outlandish speculation.

 

[joema]

There has got to be some sort of limit to the size of the explosion...

While there's an upper limit to the yield of a fission bomb, in general there's NOT an upper limit to the maximum yield on a fusion bomb.

I think the general principle is cascade more fission/fusion stages. I think 50,000 megaton devices have been studied. As the fictional character Dr. Strangelove said: "When you merely wish to bury bombs, there is no limit to the size".

However we need to launch them into space, so ratio of yield to mass (hence total mass) is limiting.

Mass of a fusion bomb increases directly with yield. The theoretical yield ratio is about 166 kg per megaton, and actual devices are somewhat lower -- say 350 kg per megaton. So even a huge Saturn V could only lift about 128,000 kg / 350 kg/mt = 365 megatons, and that's to LEO. On a deep space trajectory, probably 100 megatons.

So while a gigantic bomb could be built, there's no current launch vehicle which could lift it.

However such large devices wouldn't usually be necessary. The optimal use against an asteroid on a collision course is probably a stand-off detonation which wouldn't fragment it. The radiation flux would vaporize a layer of material, creating and opposite impulse to nudge the body off course.

You don't need a giant bomb for that. You'd probably use several smaller ones for redundancy and to incrementally change the body's trajectory.

More details in this paper (990 kb .pdf): http://www.osti.gov/bridge/servlets/purl/101350-du9CTI/webviewable/101350.PDF

 

[DaveC426913]

Therefore, I strongly feel that we definitely have the explosive means for dealing with large rouge asteriods given enough lead time and human ingenuity.

Well yeah but it's the azure ones that'll get us in the end...

 

[James Essig]

Hi Folks;

In the interest of keeping on subject and not getting to remote with far afield speculation, I will definitely refrain from making comments that may seem ludicrous to some to the extent that they may irritate or otherwise draw negative reactions from others. Bear in mind that much of my commentary as late is personal opinion and in no way necessarily represents the views of the administration of this website. My comments have seem to have drawn some strong reactions and perhaps some anger, but this is not what I am about. I meant no offense by my comments and will in the interest of harmony and cohesion among us science folks who post on this website, I will avoid any such controversially farout speculation in the future here at Physics Forums.

By the way, speaking of deflecting asteroids by stand off nuclear blasts, does anybody know how large a high yield practical neutron bomb has been designed or alledgedly designed if high yield ones have been designed. I hear the original ones where limited to about 1 kiloton.

The point I am making is what if a high yield device as such could be produced wherein its neutron flux would penetrate up to a few meters into the asteriod, causing ablative vaporization of this few meter thick layer, and as a result, cause a large momentum transfer to the asteriod. The idea is that if 10 million tons or perhaps 100 million tons of asteriod material as such can be vaporized, the average temperature and pressure of this ablated material may be similar to that of a 10 million or perhaps 100 million ton chemical bomb such as a huge TNT bomb or blackpower charge explosively propelling the asteriod out of its Earth impacting trajectory. Given that 100 million tons of TNT has the same energy as 100 million tons of matter traveling at 2.8 kilometers/second, perhaps such a kinetic energy repulsive blast could nudge an asteriod with a mass of a trillion metric tons with a velocity change 28 meters/second which is about 65 miles per hour. If intercepted a ways off, perhaps a collision course with Earth with an impactor with the power of the one that allegdedly killed off the dynosuars could be avoided.

Just a thought;

Regards;

Jim

 

[baywax]

Well yeah but it's the azure ones that'll get us in the end...

Is the Azure Plagioclase (made infamous in the melancholic song prose Miner Blues by the Gallentean folk singer Jaroud Dertier three decades ago) a fantasy asteriod from "BattleClinic" or a real asteriod?

Plagioclase is not amongst the most valuable ore types around, but it has the largest amount of pyerite of any ore and is thus always in constant demand. It also yields some tritanium and mexallon. It requires 333 ore units to refine.

http://www.battleclinic.com/eve_online/item/i17455-Azure-Plagioclase-details.html

 

[James Essig]

Hi Folks;

Its good to be back on site. I have really enjoyed the fine discussion of this thread.

If we are going to alleveate the threat of near Earth orbiting or very near Earth orbiting asteriods, maybe it is best not to even think about destroying them unless absolutely no other option could work, which seems to me an unlikely scenario. It seems to me that the asteriods might best be diverted and according to the previous comments above, perhaps they could be mined for their mineral content. Some asteriods might be of a very hard iron-nickel composition and thus might be a great source of Iron and Nickel if we could somehow learn to cost effectively bring the ore back to Earth or the space processed ore back to Earth.

At the very least, now that the Crew Exploration Vehicle that will take us back to the Moon by 2020, and perhaps in manned excursion to the Asteriods, is being developed, it would seem best to use a CEV based platform to reach the closest approaching asteriods since they would be perhaps the easiest to reach. We could prospect the asteriods and even look for rare isotopes or elements on the asteriods which might be useful back here on Earth.

Someone please tell me, Was not a layer of some element or isotope that is rare on Earth supposedly some of the first evidence that an asteriod whacked Earth to take out the dynosaurs? I remember reading or hearing about many years ago of a deposit of Iridium or some rare element found throughout the Globe in a thin layer in the geological stata that would put its time of deposition right smack when the dynosuars became extinct.

It would seem to me if we are going to divert NEOs, we should do so, if feasible in a manner that would allow them to potentially be harvested for their mineral content. We have all read and/or have heard of popular sci-fi stories and/or movies revolving around the theme of mining the asteriods. With President Bushes stated initiative to get us back to the Moon, onward to Mars, and then to "Worlds beyond", it seems that some interest within the American public in manned space travel beyond LEO and beyond the Moon is starting to be generated again. China, India, Russia, the EU, and Japan have all made statements about their desire to go to the Moon and in some cases beyond and if we don't so such, we may loose out on great opportuinities.

In short, it would seem that NEO or NEOs on collision course with Earth could be diverted and not destroyed for good purposes. It would be interesting to see just what kinds of minerals, elements, isotopes, and potentially useful radio-nucleids we might find in asteriods.

Thanks;

Jim

 

[ray b]

I wonder if we have any launch devices like a Saturn, that could be used on short notice
or if any of our war rockets can get out of orbit with a payload to get to an incoming body
in deep space
while given enough time I am sure something could be done, what is the current on line state of the art for getting a nuke up to a incoming body in say less then a week inc travel time?
it looks to me we are very ready to nuke an other country on short notice
BUT totally lack the quick ability to get a nuke into deep space to meet an incoming body QUICKLY

maybe we need to think about putting a system in orbit to be ready to meet such a case
but I think we have a treaty against nukes in space

 

[James Essig]

Hi ray b;

I completely agree with You. We might have to dissolve the treaty banning nukes from space. Even small asteriods pose great dangers to our civilization as the following scenario suggests.

Bear in mind that the asteriod which hit Tunguska Siberia had an explosive yield on the rough order of 5 to 10 megatons, its energy yield has been downgraded by a factor of about two from the initial proposed value of about 15 megatons. An airburst of a vaporizing asteriod or comet over a major metropolitan center with a yield of 25 megatons based on info provided by the Department of Homeland Security’s Web Site for a single 25 megaton nuclear airburst would have the following effects. A million metric ton asteriod vaporizing in the atmosphere traveling at 14 kilometers/second would yield 25 megatons of blast and thermal pulse energy. Such an asteriod would only be about 275 feet is diameter if it were a silicate-iron type of asteriod.

Upon detonation of the meteor at an airburst hieght of 17,500 feet, a huge fireball would form. Within a range of about 6.8 miles from the point on the ground directly beneath the blast, virtually nothing remains standing except for perhaps the shells of some of the strongest poured reinforced concrete structures near the outer periphery of this region. The airblast pressure at a radius of 6.8 miles would be about 15 to 20 pounds per square inch or up to about 1.5 tons per square foot. The immeadiate fatality rate will be atleast 98 percent. Some folks will survive at least initially because they were under ground in subways tunnels and the like. At a distance of about 10.8 miles from the hypocenter, the over pressure will still be about 5 PSI and still, their will be virtually nothing standing between the 6.8 mile contour and the 10.8 mile contour. Fifty percent of the persons within this second ring die immediately, another 45 percent are so seriously injured that virtually all of them will die in minutes or hours without emergency medical treatment which will be completely absent. Five percent will at least initially be uninjured or injured superficially. The 2 PSI contour overpressure will extent out to about 20 miles, a pressure which is still great enough to seriously damage domestic homes. In this ring, 5 percent of the persons will be killed immeadiately and 45 percent will be injured, many of the injured requiring immeadiate medical attention. In addition, fatal third degree burns can be inflicted on those out in the open as far away as 35 to 40 miles from the blast hypocenter. In actuality, it is highly likely that a firestorm will quickly develop ingulfing every thing within a 15 mile radius of the hypocenter with fatalities approaching 100 percent and flame temperatures as high as or exceeding in some cases 2,000 degrees C.


I would have to say that the radius of the mass fire storm might well be as great as 25 miles since even at this range dry vegetation, house enteriors, building interiors, ruptured fuel lines, etc, can catch fire as a result of the thermal pulse. Imagine if one of these small babies hit Tokyo, Mexico City, New Dehle, or New York City.

We really need to get these suckers before they get us!

Regards;

Jim

 

[LURCH]

I have thought for a long time now that nukes in orbit are the best solution to the threat being discussed. But the obvious dangers of such an arrangement make it unnacceptable.

My solution: orbit the Moon. If anyone wants to use theirs as a weapon, it will takes almost a week from the time they fire 'till it hits a target on Earth; plenty of time for an intercept. And if an accident causes one to fall from orbit, it falls onto the Moon, so who cares?!

If the devices need to be launched for their intended purpose, Lunar sling-shot will get them to the target faster.

Of course the one problem that remains outstandnig is getting them off the Earth and up to Lunar orbit. All I can think of is a refining process in space between here and there. Launch non-reactive materials and weaponize them at a safe distance. That is problematic, to say the least.

 

[russ_watters]

I'm not sure what issue you are concerned with that would preclude launching fully-assembled nukes. Obviously, nuclear warheads are meant to survive re-entry, so there isn't much chance of them burning up and releasing their Pu into the atmosphere.

 

[LURCH]

Given the uproar sarounding the launch of Casini, I don't think that the general public find those facts very satisfying.

However, the problem to which I'm referring is the problem of trust. If any nation tries to launch a fully assembled and functioning super-nuke into space, some other nation is likely to believe they are being fired upon, and shoot back.

 

[joema]

I wonder if we have any launch devices like a Saturn, that could be used on short notice or if any of our war rockets can get out of orbit with a payload to get to an incoming body in deep space...what is the current on line state of the art for getting a nuke up to a incoming body in say less then a week inc travel time?...maybe we need to think about putting a system in orbit to be ready to meet such a case but I think we have a treaty against nukes in space

Existing large ICBMs (Peacekeeper, Trident D-5) can probably reach escape velocity if stripped down to one warhead. They normally carry 8-12 warheads.

Although designed mainly for suborbital use, an ICBM can launch smaller payloads to Earth orbit or beyond. The Atlas and Titan ICBMs were used as orbital launchers. A Titan II lifted the Clementine probe to the moon. The Titan IIs are deactivated but available in storage for use as space launch vehicles. Don't know what the prep time would be.

Every MIRVed ICBM already has reaction thrusters on the warhead "bus", with substantial maneuvering ability. For asteroid interception, it would need an additional guidance package to enable a precision stand off detonation. That could probably be ready within weeks.

The power and thermal control systems of the bus and warheads aren't designed for long-term deep space missions. That would likely also need modification.

Current ICBMs use inertial navigation, sufficiently accurate for surface-to-surface use, but not adequate for a deep space mission. The Trident D-5 uses stellar tracking to update its inertial system.

In a dire emergency (say one week reaction time for an incoming asteroid), it's conceivable a Trident D-5 could be stripped down to one warhead, and the stellar navigation software updated. That way no terminal guidance package would require development. However power, etc are designed for a 30-min mission, not several days in deep space.

It's true the 1996 Comprehensive Test Ban Treaty apparently prohibits detonation of nuclear weapons in space. However a closer reading includes the clause "at any place under its jurisdiction or control".

This was probably added for wartime use of nuclear weapons on enemy territory -- an area not under the jurisdiction or control of the launching nation.

Similarly, there's a good argument that deep space is not under the jurisdiction or control of any nation, so the treaty might not apply in that case.

 

[James Essig]

Hi joema;

Good analysis!

Given that the yield of a typical warhead currently in service is about 1/2 megaton namely the 475 kiloton yield for the W-88 stationed aboard Ohio Class Boats, a stand off detonation or an asteriod sub-surface detonation may be our only hope given a few weeks notice. If only half of the explosive energy of a W-88 was converted to net asteriod change in kinetic energy for a one billion metric ton asteriod, the net kinetic energy delivered to the asteriod would be equivalent to about a 45 meter per second velocity difference which is not trivial. Given two weeks of time, 45 meters per second translates into 45 x (10 Exp 6) meters = 45,000 kilometers ~ 7.5 Earth Radii. Such a modest but still amazingly powerful W-88 might just do the job.

But what if we are confronted with a dark colored trillion metric ton class asteriod which is simmilar in size to the one that supposedly killed off the dynosuars, for an iron silicate rock, the diamter would be about 8 kilometers or 5 miles. A 100 megaton stand of blast or perhaps a 100 megaton sub surface detonation might impart a delta V of about 15 meters/sec for a distance change over 2 weeks of 15,000 Kilometers or about 2.3 Earth radii. The good old fashioned Russian Nukes of 100 megatons that were rumored to have been deployed during the Early 1960s might just save the day. We would need to use the space shuttle or one of Russia's fine workhorse heavy lift boosters to get the sucker into orbit along with its rocket propulsion system. Perhaps some ultra hard steel casing could make a deep penetration warhead out of this 100 megaton monster such as the use of the alledged super hard and super strong steel developed at Eglin Air force base for bunker buster weapons.

I would hope that mankind could gin something up to stop a dynasour event like rock from slamming us dead. Hopefully, we could divert the asteriod without slamming it into planetary buckshot.

Regards;

Jim

 

[Oberst Villa]

Given that the yield of a typical warhead currently in service is about 1/2 megaton namely the 475 kiloton yield for the W-88 stationed aboard Ohio Class Boats, a stand off detonation or an asteriod sub-surface detonation may be our only hope given a few weeks notice. If only half of the explosive energy of a W-88 was converted to net asteriod change in kinetic energy for a one billion metric ton asteriod, the net kinetic energy delivered to the asteriod would be equivalent to about a 45 meter per second velocity difference which is not trivial.

I think your assumption that "only" half of the explosive energy of the warhead is converted into kinetic energy for the asteroid is in fact too optimistic. (at least if you consider a stand-off detonation, sub-surface might be better)

if you consider a spherical symmetric explosion over a flat plane in vacuum, it is clear to see that only half of the energy is going into the direction of the plane, while the other half is just going into empty space.

now consider the 50% of energy going into the direction of the asteroid. even if all of this could be used to ablate the surface of the asteroid (so that the ejected material will provide an impulse into the opposite direction for the asteroid), the ejected material itself will also carry some of the energy away. so even under the most optimistic assumption, 50% of the original energy of the explosion can never be available as kinetic energy for the asteroid alone. there would be other effects eating away the energy, e.g. the shock wave going to the asteroid after its surface is explosively ejected would certainly warm it up, further reducing the kinetic energy.

all this is not to say that I think what you propose should not work in principle. just ask the friendly submarine commander in your neighbourhood to supply you with a warhead that is a little bigger than the W-88

 

[James Essig]

Hi Oberst Villa;

Thanks for the insights. The only conceivable warheads that would direct more than 50 percent of their energy to the asteriod in a stand off blast are perhaps some of the proposed directed energy Nukes which I have no idea if they have ever been assembled not to meantion whether or not they have ever been fielded.

Those other losses would, as you say, pose further restriction on the amount of KE delivered to the asteriod percentage-wise. I think for a billion metric ton asteriod, a significantly higher yield warhead then the W-88 would be required or perhaps several hits from W-88s in sucession might do the job. Hopefully, we would not fragment the rock in the process.

Regards;

Jim