How Can We Effectively Destroy An Asteroid Headed for Earth?

[Morbius]

However it's not necessary that nuclear explosions in space be tested against actual asteroids before attempting a deflection. Nor is it necessary to know it would work. It would be nice additional information, as more quality data is generally better. However nuclear explosions have been tested thousands of times on earth. The effects on materials are well understood. In some tests a vacuum chamber was positioned adjacent to the device to measure effects against materials in a vacuum.

joema,

Yes - back in the days when the USA conducted nuclear tests; such tests were made by
the Dept. of Energy for the Dept of Defense in long horizontal tunnel shots:

http://www.nv.doe.gov/library/publications/newsviews/tunnel.htm

Dr. Gregory Greenman
Physicist

 

[Aero Stud]

I was simply responding to your statement that nuclear devices have never been detonated in space, which they have. I wasn't saying they were used to deflect or destroy satellites; to my knowledge they haven't been.

I was basing it on what's written in the link you posted with the different detonations listed. They say several sattelites were destroyed (I'm guessing they just short circuited due to EMP, but maybe some were directly hit by the blast).

 

[joema]

The electronics in those satellites were damaged by the radiation, either direct or indirect. Whether it was EMP, neutron, gamma radiation or a perturbation of radiation belts around earth, I don't know. E.g, satellites not properly rad hardened can be damaged by passing through the South Atlantic Anomaly: http://en.wikipedia.org/wiki/South_Atlantic_Anomaly

It wouldn't be from blast, as there is no blast in space -- no atmosphere to form a blast wave.

They key item in calculating asteroid deflection is how the material reacts the ablative radiation burst from a stand off detonation. I'm sure the materials science of that is well understood from the 2,000+ nuclear tests that have already happened. Nowadays sophisticated computer modeling can take that base data and extrapolate based on various possible asteroid material compositions.

The vacuum of space actually simplifies things in that you have no blast wave to worry about.

However we don't know much about the composition of asteroids and comets. The Deep Impact mission helped some: http://en.wikipedia.org/wiki/Deep_Impact_(space_mission)

We're also blind to approach trajectories near the sun. The European Gaia probe might help this when launched in 2011: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29806

The European Don Quijote probe will attempt an asteroid impact to measure the achievable deflection. This will also reveal information about the asteroid's physical makeup: http://www.esa.int/esaCP/SEML9B8X9DE_index_0.html

 

[Chronos]

The physics are pretty simple - no matter, no matter to propagate a shock wave. A nuclear detonation would not be effective unless near enough to the asteroid to vaporize enough mass to propagate a shock wave. It might be possible to achieve the desired effect through a carefully timed sequence of detonations. The one thing you really should try to avoid is breaking up a large asteroid into a collosal menage of Mt. Everest sized fragments.

 

[Morbius]

The physics are pretty simple - no matter, no matter to propagate a shock wave. A nuclear detonation would not be effective unless near enough to the asteroid to vaporize enough mass to propagate a shock wave.

Chronos,

I'm sorry - but you are wrong here.

As long as you vaporize mass, and some of that mass ablates in the direction of the
bomb; the asteroid will recoil in order to conserve momentum. Hence there will be an
impulse to the asteroid.

The impulse doesn't have to be strong enough to propagate a shock wave. You get a
shock wave when the distrurbance attempts to propagate through a medium at a
speed in excess of the speed of sound in that medium.

The conservation of momentum is INDEPENDENT of whether the disturbance propagates
subsonically, or supersonically. Therefore, the recoil of the asteroid, and hence the
impulse delivered to it is also INDEPENDENT of whether the disturbance is subsonic or
supersonic.

Dr. Gregory Greenman
Physicist

 

[joema]

...no matter, no matter to propagate a shock wave. A nuclear detonation would not be effective unless near enough to the asteroid to vaporize enough mass to propagate a shock wave...

Clarifying for other readers: there'd be no atmospheric blast wave or shock wave as seen within the Earth's atmosphere. There might be a shock wave within the asteroid material, produced when the X and neutron radiation from a stand-off detonation vaporizes a thin layer of surface material.

The two separate effects (radiation vs blast) can clearly be seen from video of past nuclear tests.

About 30 sec into the below video, the surface of several vehicles and structures are vaporized by a nuclear explosion, yet they aren't demolished -- until the blast wave later arrives.

In space there would only be the initial vaporization, no blast wave.

http://video.google.com/videoplay?docid=-8173791211944754735

 

[Morbius]

Clarifying for other readers: there'd be no atmospheric blast wave or shock wave as seen within the Earth's atmosphere. There might be a shock wave within the asteroid material, produced when the X and neutron radiation from a stand-off detonation vaporizes a thin layer of surface material.

joema,

Correct you are.

There's no blast or shock wave in space between the bomb and asteroid.

There will be an impulse on the asteroid do to ablation caused by the radiation.

Whether that results in a subsonic wave or supersonic wave , i.e. shockwave,
depends on how strong the ablation is; but either way, there will be an impulse
delivered to the asteroid.

Dr. Gregory Greenman
Physicist

 

[Westic]

This is a thoroughly entertaining thread.
My first post.
Morbius you are definitely one of THE most patient and gracious persons on the face of this planet. LOL

 

[Sojourner01]

The primary objective, naturally, is deflection.

However, it would also be beneficial to get rid of the damn thing for good. Is it plausible to do precise enough dynamical calculations ahead-of-time in order to not only deflect an obejct from near earth, but ensure that its orbit takes it into either the sun or one of the gas giants? boy, that'd be a spectacle. Can you imagine what we'd learn from Jupiter if we could bung an asteroid the size of a small moon into it and watch what it stirs up?

 

[baywax]

Would fixing some rocket engines on to the asteroid help to deflect it? Just use a joystick to save earth. I guess the hard part would be getting on the surface with the engines, then positioning properly.

 

[Morbius]

Would fixing some rocket engines on to the asteroid help to deflect it? Just use a joystick to save earth. I guess the hard part would be getting on the surface with the engines, then positioning properly.

baywax

Depends on the orbit of the asteroid, how big it is...

Basically, it depends on how much energy would it take to deflect it, and how much
time you have.

If the asteroid is very massive, and it will hit us on its current orbit; then you may need to
put so much energy into it that NO chemical rocket could put that much energy in. There
would be NO chemical rocket that is powerful enough to deflect it.

There might even be an asteroid too massive for a nuclear weapon to deflect.

In which case, the Earh is doomed.

Dr. Gregory Greenman
Physicist

 

[Morbius]

The primary objective, naturally, is deflection.

However, it would also be beneficial to get rid of the damn thing for good. Is it plausible to do precise enough dynamical calculations ahead-of-time in order to not only deflect an obejct from near earth, but ensure that its orbit takes it into either the sun or one of the gas giants?

Sojourner01,

All depends on how much energy is required. These are massive objects, and we really
don't have a lot of energy available.

In cosmological terms; the forces of Nature at our command are pretty puny.

Dr. Gregory Greenman
Physicist

 

[Sojourner01]

Well, what I'm getting at is that assuming you can deflect the object from earth, are our computational methods precise enough to ensure that its new trajectory will put it where we want it? I'm sure the answer to this question will depend on where in the risky trajectory you choose to act - further away from Earth you don't need as much of a jolt, but that also puts it further away from its intended destination. I ask because I'm aware that astronomers can't say with complete certainty whether or not a particular object will strike us in the future; there's a 'window' limited by their ability to compute the dynamics of all the bodies involved ahead of time. what I'm asking is, does this inaccuracy extend to us altering the path of a large object, assuming we're practically able to?

 

[Morbius]

Well, what I'm getting at is that assuming you can deflect the object from earth, are our computational methods precise enough to ensure that its new trajectory will put it where we want it?

Sojourner01,

Oh sure to the computational methods.

Take, for instance, the Cassini mission. We had insufficient propulsion systems to launch
Cassini directly to Saturn; so it was launched in a trajectory that caused it to make TWO
fly-bys of Venus, in order to pick-up momentum via the "sling-shot" effect; before it went
to Saturn.

http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1997-061A

If we can accurately "hit" the rings of Saturn by making two "bank-shots" off of Venus;
then we can calculate how to deflect the asteroid.

Dr. Gregory Greenman
Physicist

 

[mr200backstrok]

this is a little off topic, but is there an upper limit for the yield of thermonuclear bombs?

 

[joema]

this is a little off topic, but is there an upper limit for the yield of thermonuclear bombs?

To my knowledge, there is no upper yield limit. In principle, by cascading fission/fusion/fission stages, any size weapon could be constructed. I believe 50,000 megaton devices have been studied: http://en.wikipedia.org/wiki/Nuclear_weapon_yield

However there is a limit to the yield per unit weight. The absolute maximum theoretical yield is 166 kg per megaton, and that's just for the nuclear material itself. Actual achievable yield from real-world warheads is closer to 350-400 kg per megaton.

Stated differently, the maximum yield ratio thus far achieved is 5.2 megatons per metric ton, so a 200 megaton device would weigh 38.5 metric tons (84,877 lbs).

The Saturn V payload to lunar escape velocity was about 47 metric tons, so largest bomb it could lift on that trajectory would be "only" 244 megatons.

An asteroid intercept would likely require a higher energy trajectory, which means lower payload. Just guessing, say about 100 megatons on a Saturn V.

 

[Morbius]

this is a little off topic, but is there an upper limit for the yield of thermonuclear bombs?

mr200backstrok,

Unlike fission weapons, there is no upper limit nor lower limit to the yield of a
thermonuclear bomb [ provided you can ignite it ].

Consider the lower limit. The small fusion pellets that would undergo thermonuclear
fusion in ICF - Inertial Confinement Fusion are, in essence; small thermonuclear "bombs".
The problem is it takes an awfully large machine, like a laser the size of a football stadium
to ignite it.

In fission bombs; there is a lower limit because there is a "critical mass". You don't get
a self-sustaining fission reaction until you have a certain minimum amount of material,
called the "critical mass". Once you get the fission reaction started in a fission bomb
by having the minimum amount of bomb fuel - then you have enough fuel there for a
yield that is very sizeable compared with conventional chemical explosives.

In practice, the thermonuclear bombs are "triggered" by a fission bomb; so there is a
minimum possible yield to a real thermonuclear bomb because there is a minimum yield
for the device that triggers it.

The largest bomb ever designed was the "Tsar Bomba" - "King of the Bombs" - which
the Russians designed to have a yield of 100 megatonnes. They actually tested a
reduced yield version of this bomb with a yield of 54 megatonnes. That test was the
largest yield nuclear test ever conducted.

Dr. Gregory Greenman
Physicist

 

[Morbius]

To my knowledge, there is no upper yield limit. In principle, by cascading fission/fusion/fission stages, any size weapon could be constructed. I believe 50,000 megaton devices have been studied: http://en.wikipedia.org/wiki/Nuclear_weapon_yield

joema,

You're off by a factor of 1,000!

The table in the Wikipedia article you reference gives the yield of the Tsar Bomb as
50,000 in units of KILOTONS. That would be 50 Megatonnes; not 50,000 Megatonnes.

Dr. Gregory Greenman
Physicist

 

[joema]

...You're off by a factor of 1,000!...The table in the Wikipedia article you reference gives the yield of the Tsar Bomb as
50,000 in units of KILOTONS. That would be 50 Megatonnes; not 50,000 Megatonnes...

Sorry, I was referring to theoretical weapons which have been studied, not actual detonations. I referenced the article to show the basic principles of nuclear weapon yield, and the chart which shows there's a yield-to-weight limit but no upper yield limit: http://en.wikipedia.org/wiki/Image:US_nuclear_weapons_yield-to-weight_comparison.svg

I don't have the ref, but I believe in the 1950s and 60s, Rand Corp. studied unitary Cobalt-salted devices with yields up to 50,000 megatons. They concluded there was no upper yield limit, and then-current engineering would allow construction.

However from an asteroid deflection standpoint, there's no way to deliver such a device, as it's far too heavy for even the largest launch vehicle. It would take a vehicle at least 100x the payload capacity of a Saturn V.

 

[mr200backstrok]

Sorry, I was referring to theoretical weapons which have been studied, not actual detonations. I referenced the article to show the basic principles of nuclear weapon yield, and the chart which shows there's a yield-to-weight limit but no upper yield limit: http://en.wikipedia.org/wiki/Image:US_nuclear_weapons_yield-to-weight_comparison.svg

that one is measured in kt. if you look at the left side of the chart, it says "yield (kt)".

That kind of power is insane...

 

[joema]

that one is measured in kt. if you look at the left side of the chart, it says "yield (kt)"...

Yes, I know it says yield in kt. But just as the horizontal axis shows weight in kg up to 10^5 kg, there is in fact no upper weight limit, nor any yield limit.

 

[Morbius]

I don't have the ref, but I believe in the 1950s and 60s, Rand Corp. studied unitary Cobalt-salted devices with yields up to 50,000 megatons. They concluded there was no upper yield limit, and then-current engineering would allow construction.

joema,

Rand Corp. doesn't design nuclear weapons; or even know how the current ones work.

There are ONLY two places in the USA where the design knowledge for thermonuclear
weapons exists; and that's at Los Alamos and Lawrence Livermore.

So I wouldn't put any credance in anything out of Rand when it comes to nuclear
weapons design.

Dr. Gregory Greenman
Physicist

 

[joema]

joema,

Rand Corp. doesn't design nuclear weapons; or even know how the current ones work...

Thanks for the correction. Maybe it wasn't RAND.

True LANL and LLNL are the centers of actual weapon design, and past RAND research focused more on weapon effects than design. However RAND participants have included former Los Alamos and Lawrence Livermore physicists. Two examples:

- Harold L. Brode, physicist, and pioneer of numerical simulations of nuclear explosions
- Samuel Cohen, inventor of neutron bomb

None of this changes the answer to the poster's question: there's no upper limit to the maximum size of a nuclear warhead, but the yield-to-weight ratio imposes a practical limit based on current launch vehicle payload capacity.

 

[Morbius]

- Harold L. Brode, physicist, and pioneer of numerical simulations of nuclear explosions

Harold L Brode was a physicist at RAND that simulated nuclear weapons effects -
NOT the bomb itself. The only places where the nuclear weapon itself is simulated
in the USA is at Los Alamos and Lawrence Livermore.

- Samuel Cohen, inventor of neutron bomb

Cohen is the "self-proclaimed" inventor of the neutron bomb.

However, the devices that were once in the USA's stockpile called "neutron bombs"
dating from the '70s were the W-79 Mod 0 artillery shells and they
were invented by scientists at Lawrence Livermore; NOT Cohen.

None of this changes the answer to the poster's question: there's no upper limit to the maximum size of a nuclear warhead, but the yield-to-weight ratio imposes a practical limit based on current launch vehicle payload capacity.

There's no theoretical upper limit to the yield of a thermonuclear weapon.
A fission weapon does have lower and upper limits.
However, since a thermonuclear weapon needs to be "triggered" by a fission weapon, and the fission weapon
has a lower yield limit; the thermonuclear weapon has an effective lower limit, because its trigger does.

BTW, check your Physics Forum Private Messages.

Dr. Gregory Greenman
Physicist

 

[xllhawksllx]

Thats a horrible idea, as you said it would send thousands of pieces towards earth. Most likely, the solution would be to push the asteroid out or somehow detonate it where it would split into and somehow well that remains to be figured in how to deal with the remaining pieces.

 

[Morbius]

Thats a horrible idea, as you said it would send thousands of pieces towards earth. Most likely, the solution would be to push the asteroid out or somehow detonate it where it would split into and somehow well that remains to be figured in how to deal with the remaining pieces.

xllhawksllx,

You don't understand how you use a nuclear device to deflect an asteroid.

You don't "blow up" the asteroid. You detonate the nuclear weapon at a stand-off
distance from the asteroid. The radiation from the nuclear weapon ablates the surface
of the asteroid, which causes it to recoil.

The nuclear weapon PUSHES the asteroid; it doesn't "blow it up".

For a large asteroid, a nuclear weapon may be the ONLY HOPE; because only a
nuclear weapon has enough energy to deflect a large asteroid in a package that
is light enough for us to launch into space.

Dr. Gregory Greenman
Physicist

 

[James Essig]

Extreme Size of Thermonuclear Devices for Space Based Planetary Protective Measures

There are a number of ways extremely large nuclear devices could be fabricated for any of a wide variety of extreme planetary defense scenarios.

The first such scenario involves destroying a distant but inward bound asteriod or planetary body of extreme size. Note that the destruction of such a large body is possible if given enough time to fabricate a large enough nuclear device in Earth or Solar orbit. One can consider an extreme but rather absurd case wherein a global society might want to construct a thermonuclear device comprising 10 EXP 15 metric tons of fusionable material of simmilar construction to a fission-fusion-fusion device. Such a device would have a yield of approximately 10 EXP 23 tons of TNT or about 50 times the mass of the Earth in TNT which is roughly equivalent to the heat of vaporization of a typical mass of solid ordinary planetary materials with total mass equal to (n)(50)(Me) where n ranges from unity to 10 and depends on the materials and Me is the mass of the Earth. Such a device, if utilizing a dense hydrogenic compound for fusion fuel such as Lithium Dueteride, would have a diameter on the order of 100 kilometers.

The fusionable fuel for such a device would have to be collected from Earth and/or other planetary bodies and perhaps comets which comprise a large percentage of their material in the form of low atomic number exothermically fusionable elements. Thus such a large device would not be practicable nor possible to construct rapidly enough to respond to near term planetary emergencies such as the near term threat of a huge asteriod collision.

A more likely scenario for the use of devices this large and larger would involve the threat of extraterrestrial biological organisms such as may exist within a interstellar dust cloud in the form of exotic dangerous micro-organisms or any other simmilar interstellar threat. Such a threat in unlikely to be discovered any time soon and such a discovery would probably entail the ability and infrastructure in possession of future humanity to travel throughout interstellar space for which there have been suggested and studied numerous propulsion techniques that do not require any fundamental physics beyond what has already been commonly excepted and utilized on a wide scale in industry and research throughout the Globe.

One can, for instance, imagine the collection of cometary material from say the Kuiper Belt and/or the Oort cloud by intentionally directing comets in relatively slow collisions amongs themselves until a planetary body sized collection of low atomic number elements and their various isotopic forms has been accumulated. A means for purifying the collected material to form a planet sized nuclear device of precisely manufactured material content might be required to produce a workable thermonuclear device or perhaps the collected material could be ignited without refinement. In the later case, perhaps one or more large enough secondary nuclear devices could be used to initiate the
fusion of the collected mass at various locations wherein the process of fusion would quickly spread throughout the entire planetary mass until all of the collected fusionable material has fused. As another option, perhaps one or more large shaped charged nuclear fusion devices could produce the critical pressures required to initiate self propagating fusion reactions throughout the collected material. Note that a nuclear fusion device with the mass of the Earth would have a yield of roughly 10 EXP 29 tons of TNT or roughly the mass of TNT of two orders of magnitude greater than the approximate 10 EXP 27 metric tons mass of the Sun.

Although larger devices would seem to have no obvious conceivable purposes, one can even imagine as a very, very long term stellar engineering project, the very gradual construction of a thermonuclear device with the mass of a white dwarf star wherein the materials of construction would be supercooled at the construction site and gradually assembled and with a means for radiative heat exhaustion whereby the collection of matter could be built up in such a manner that it would not ignite and form a star. Obviously, a means would have to be devised to cope with the extreme gravitational forces on the surface of the growing orb which would eventually become, in a sense, a white dwarf as its increasing mass caused gravity induced self compression into white dwarf like matter densities.

As yet an even more extreme case, one can imagine the construction of a huge toriodal ring with the diameter of our planetary solar system comprising a mass of 10 EXP 5 to 10 EXP 6 solar masses of fusionable fuel wherein the torus would be gradually spun up as it is constructed in order to prevent gravitational collapse of the device as its mass increases. Accordingly, the device could be constructed at symmetrically disposed locations about a circle in either a discreet or continuous fashion. As the device neared completion, its final rotational velocity would be several hundreds of kilometers per second and the rotational velocity of the device would be designed along with the major diameter, thickness, and mechanical strength of the material composition of the torus in such a manner that the tidal forces acting on portions of the torus between locations at different radial distances from the center of the torus would have minimal effect. The torus when fully constructed would preferably be dense enough so that, even given its extreme size, its density would be close to that of a white dwarf inorder to provide a potentially much more stable and thin torus. For a torus having a 10 EXP 10 kilometer circumference, a mass of 10 EXP 6 solar masses, and a thickness of 10,000 kilometers. the density of the torus would approach that of a white dwarf.

Much larger torus shaped nuclear devices may be possible, but at the risk of boring the reader with absurdity, these more extreme versions will not be discussed here.

The point to be made here is that, literally speaking, there is no upper limit to the mass of a thermonuclear device. Why would mankind choose to produce the extreme sized devices described above is amyones guess. However, it may be useful to point out that the cosmos over long time frames is a metaphorical shooting gallery. One has to merely recall the event that supposedly wiped out the dinosaurs and realize that over a long enough time period, most probably, even larger threats will present themselves. If we are going to plan for the survival of mankind for the next thousand years, why not plan for our survival essentially for eternity.

 

[Astronuc]

The point to be made here is that, literally speaking, there is no upper limit to the mass of a thermonuclear device.

Um - there is a practical limit in which the yield is limited by the size, such that it would be impractical to build a large device. In addition to the yield, there is the matter of delivering the device. The bigger the device, the larger the propulsion system necessary to deliver it.

Pardon me, but a device based on 10¹⁵ metric tons of fusionable material is absurd!

 

[James Essig]

Hi Astronuc;

Thanks for the feedback.

A much more practical 1,000 megatons to safety destroy a 1/4 mile wide or even a 1/3 mile wide asteriod might be doable providing at least one third of the bombs energy can be deposited within the asteriod's material composition. 1,000 megatons of TNT releases the energy required to completely vaporize 2 cubic kilometers of water ice and because of the relatively lower specific heat and heat of vaporization of many solid minerals and metals roughly, an equal volume of rock and metal may be vaporized depending on the minerals and metals in question. Note that even though it is relatively easy to bring water from freezing to boiling, the heat of vaporization of water is about 1.85 megajoules/kilogram as opposed to the 0.420 megajoules/kilogram necessary to heat liquid water just above freezing to boiling temperature. The specific heat of water and its heat of vaporization is about as high as they come for ordinary materials.

Note that a 1 megaton nuclear warhead detonation in a surface blast will produce a crater 1,000 feet across and 200 feet deep in granite. Much of the ejected material would be vaporized in a surface blast and much of the remainder that is not vaporized will be pulverized into dust and or grainular pebble sized material. Based on the 1/3 route scaling of crater depth with yield, a 1,000 megaton device would produce a crater 10,000 feet across and 2,000 feet deep. Even based on the perhaps more precise EXP 0.31 dependence of crater size with incremental yield increase where the depth of the crater for a nuclear device detonated at Earth's surface scales as the EXP 0.31 incremental yield increase, we are still talking about a crater depth of at least 1/3 of a mile.

A good question would be how to effectively couple the bombs blast energy to the asteriodal material without causing it to break into smaller pieces. Perhaps using a robust deep asteriod penetration mechanism simmilar to the robust deep Earth penetration techniques studied within the U.S. defense establishment could be used to produce a much greater coupling between the bomb energy and the asteriodal material. Note that as big as the craters produced by surface detonations of nuclear weapons are, much of the weapons total energy is reflected back upward away from the ground so that more effective coupling of the blast energy to the ground as in a sub-surface burst produces a crater of considerably greater dimensions.

Another option would be to use a 1,000 megaton device in the form of a directed energy nuclear device such as a shaped charged nuclear device that would produce directed energy in the form of a much hotter, much higher pressured, and much higher velocity jet in a simmilar manner utilized by conventional shaped charged explosive devices used to defeat heavilly armoured vehicles. Some publically available sources quote the maximum potential explosive energy flux density from such a device as much as 6 orders of magnitude greater than that achievable by a traditional spherically symmetric nuclear detonation. Just as an interesting aside, this upper range for shaped charged nuclear explosives corresponds to a kinetic energy of protons within the explosion of about 10 TeV. This is within the range to be studied by the upgraded LHC of CERN in an attempt to discover the Higgs Bosons which are believed to be the quanta of the Higgs Fields which according to the Standard Model of Particles and Fields, is the mechanism responsable for mass generation and inertia for all known particles having mass in our universe.

The mattergy jet produced by a nuclear shaped charge device of 1,000 megaton yield might be just the right mechanism to effectively couple the blast energy to the asteriod providing that a large portion of the total energy of the blast can be incorporated within the jet.

For larger asteriods, larger devices could be constructed. Note that the approximate alledged 400 kilograms per megaton as the maximum mass specific yield of a nuclear device might not be valid if a large enough supply of fusionable fuel can be appropriately disposed around the fission primary of the thermonuclear device. Note that just one kilogram of hydrogen fully fusioned via the proton proton reaction cycle has a yield of about 200 kilotons. If such a reaction could propagate through a 100 metric ton thermonuclear device that is mostly hydrogen with about 95% or greater efficiency, then a 100 metric ton device based on the proton proton cycle could have a staggering yield approaching 20,000 megatons or a whopping 20 gigatons. I would think that this size of a device could be developed and llifted into low Earth orbit by the ARES V booster under development to lift into orbit the components of the CEV that will take mankind back to the Moon by about the year 2020. The large rocket propulsion system to accellerate this monster device to target an asteriod could be separately lofted by another ARES V booster wherein the two components would be assembled in low Earth orbit.

Best Regards;

Jim

 

[James Essig]

I would like to wish all of the readership of this site and your families and loved ones a great New Year and many more to follow.

Regards;

Jim