Atomic/Nuclear Bombs in Space: Oxygen Required?

[b.conway]

Can atomic or nuclear bombs be detonated in space? There is no oxygen and I was wondering in an effort to deter an asteroid if they really could be used - do they need oxygen to work?

For example would they work if you fired one to the moon?

 

[etudiant]

There is no problem to detonating a nuclear device in space.
A large (1.4 megaton) device was exploded over the Pacific during the US 1962 test series.
Look up Starfish Prime, the name of the test, on Goggle.
The electronic pulse of the bomb set off burglar alarms in Hawaii, over 800 miles away.
There is speculation that a similar explosion today over the continental US would fry essentially all solid state electronics except for some heavily shielded military gear. However, it is so difficult to protect against this kind of pulse that nothing has been done to provide even a basic infrastructure fallback.

 

[Drakkith]

Just wanted to point out that an EMP would NOT occur further out away from the Earth's atmosphere. (Or rather, that it would be drastically less severe) A large part of the EMP is from the blast interacting with the atmosphere and generated large amount of charged particles and EM radiation.

In response to the OP:
A nuclear weapon does NOT burn or explode like a conventional explosive. Let's look at a common scenario, a campfire. The wood in the fire contains large amounts of Carbon, which is an element. When heated to a sufficiently high degree, this carbon REACTS with the Oxygen in the air. This reaction is the bonding of Carbon to Oxygen. This bonding releases energy which is then used to heat up further Carbon and Oxygen and keep the process going. So you get a fire.

A basic nuclear weapon uses a very heavy element, typically Uranium or Plutonium, as fuel. Instead of taking the Uranium and bonding it to another element like oxygen, we bombard it with a subatomic particle called a Neutron. This neutron causes the Nucleus of the Uranium, which contains large amounts of Protons and other Neutrons, to split and release large amounts of energy. (About a million times more than the bonding between Carbon and Oxygen releases) But this nucleus ALSO releases other neutrons. These other neutrons hit other Uranium nuclei and cause a chain reaction similar to the way the energy released from bonding Carbon and Oxygen together causes the fire to conitune. An uncontrolled reaction is the result in a nuclear bomb, while the steady production of heat is the result in a nuclear power plant.

For more information see here:
http://en.wikipedia.org/wiki/Nuclear_fission
http://en.wikipedia.org/wiki/Combustion

 

[Morbius]

Can atomic or nuclear bombs be detonated in space? There is no oxygen and I was wondering in an effort to deter an asteroid if they really could be used - do they need oxygen to work?

For example would they work if you fired one to the moon?

Nuclear weapons don't need oxygen to work. Fuels need oxygen to burn because "burning" is a chemical reaction - oxidation. Nuclear bombs work with nuclear energy.

Scientists are already studying how to use nuclear weapons to save the Earth from errant asteroids. You don't want to blow it up - you just want to change it's orbit. You do that by speeding it up or slowing it down. You do that by having the bomb just in front of, or just behind the asteroid when you detonate it. Radiation from the bomb will vaporize some of the asteroid surface, and the recoil from that material leaving the asteroid is what will either accelerate or decelerate the asteroid.

Courtesy of Lawrence Livermore National Laboratory:

https://newsline.llnl.gov/_rev02/articles/2009/apr/04.24.09-dearborn.php

Dr. Gregory Greenman

 

[mheslep]

...

Courtesy of Lawrence Livermore National Laboratory:

https://newsline.llnl.gov/_rev02/articles/2009/apr/04.24.09-dearborn.php

Dr. Gregory Greenman

Until LLNL becomes a charitable organization the work comes from LLNL, the courtesy comes from US taxpayers.

 

[Joseph Chikva]

Nuclear weapons don't need oxygen to work. Fuels need oxygen to burn because "burning" is a chemical reaction - oxidation. Nuclear bombs work with nuclear energy.

Scientists are already studying how to use nuclear weapons to save the Earth from errant asteroids. You don't want to blow it up - you just want to change it's orbit. You do that by speeding it up or slowing it down. You do that by having the bomb just in front of, or just behind the asteroid when you detonate it. Radiation from the bomb will vaporize some of the asteroid surface, and the recoil from that material leaving the asteroid is what will either accelerate or decelerate the asteroid.

Courtesy of Lawrence Livermore National Laboratory:

https://newsline.llnl.gov/_rev02/articles/2009/apr/04.24.09-dearborn.php

Dr. Gregory Greenman

Even convential high explosive (chemical) used for fission bomb triggering does not use any external oxygen. And in US owned nuclear weapon as I know the TATB explosive is used http://en.wikipedia.org/wiki/TATB due to its “insensitive properties”

But as I know the method to explode bomb at asteroid's surface for changing its trajectory now considering as ineffective.
More effective to use kinetic energy for that.
Similar to how should to be intercepted antiship missiles (sea skimmers) with the help of Rolling Airframe Missiles (RAM) http://en.wikipedia.org/wiki/RIM-116_Rolling_Airframe_Missile or Ballistic Missiles with the help of Terminal High Altitude Area Defense (THAAD) http://en.wikipedia.org/wiki/Terminal_High_Altitude_Area_Defense .
For note: THAAD does not use any explosive in its warhead for destroy the enemy missile but uses the so called “Kill Vehicle”. As blast does not guarantee that missile even damaged will change its trajectory.

 

[Drakkith]

You know, I was thinking the same thing Joseph. I always wondered how effective a nuke would actually be at diverting an asteroid, and if simply ramming something into it a high speed would work better.

 

[Joseph Chikva]

You know, I was thinking the same thing Joseph. I always wondered how effective a nuke would actually be at diverting an asteroid, and if simply ramming something into it a high speed would work better.

That is not my idea.
But people who really are engaged with warships' security have proved that conventional air defence missiles with blast-fragmentation warheads are inefficient against sea skimmers. As those last flying at low altitude, having a big mass and augmented warheads, even damaged only by fragments then continue flying to the ship like a thrown parallelly to water flat stone.
And so, more effective is a direct hit passing to approaching missile the some angular momentum.
That is proved fact.

In considered here case as well - as direct hit would be more effective than the reactive momentum caused by ablation jet of target (asteroid).

 

[HowlerMonkey]

A nuke creates a blast by superheating matter within it's proximity causing it to expand greatly.

If a nuke is detonated in the near perfect vacuum of space, there isn't anything more than the matter contained within the bomb itself that will expand.

 

[Joseph Chikva]

As I understand they mean that asteroid's matter as such should be ablated at the expense of nuke heat.

 

[Morbius]

Until LLNL becomes a charitable organization the work comes from LLNL, the courtesy comes from US taxpayers.

mheslep,

Evidently you are not up on current events. Lawrence Livermore and Los Alamos are no longer run by public entities. The US Congress saw fit to PRIVATIZE the nuclear weapons design labs a few years ago.

Lawrence Livermore is now run by an "LLC" - a "limited liability corporation", called "Lawrence Livermore National Security", LLNS (pronounced "lins" ) for short. The major partners in this private company are University of California Regents and Bechtel, along with some junior partners like Texas A&M University:

http://llnsllc.com/

The Dept of Energy is now a "customer"; just like the Pentagon is a "customer" for Boeing, Lockheed, or General Dynamics.

Dr. Gregory Greenman

 

[Joseph Chikva]

mheslep,

Evidently you are not up on current events. Lawrence Livermore and Los Alamos are no longer run by public entities. The US Congress saw fit to PRIVATIZE the nuclear weapons design labs a few years ago.

Lawrence Livermore is now run by an "LLC" - a "limited liability corporation", called "Lawrence Livermore National Security", LLNS (pronounced "lins" ) for short. The major partners in this private company are University of California Regents and Bechtel, along with some junior partners like Texas A&M University:

http://llnsllc.com/

The Dept of Energy is now a "customer"; just like the Pentagon is a "customer" for Boeing, Lockheed, or General Dynamics.

Dr. Gregory Greenman

What's a difference who is owner if we talk about effectiveness of method? Yes, we can say that nuke bomb as well as chemical high explosive can blast in vacuum. But for what?

 

[Morbius]

What's a difference who is owner if we talk about effectiveness of method?

I would agree - but mheslep thought there was something important about who ran the lab.

Why not ask him?

Dr. Gregory Greenman

 

[Morbius]

A nuke creates a blast by superheating matter within it's proximity causing it to expand greatly.

If a nuke is detonated in the near perfect vacuum of space, there isn't anything more than the matter contained within the bomb itself that will expand.

Howler Monkey,

NOPE - it's more complicated than that.

The radiation that comes off the bomb will vaporize a bunch of the matter in the asteroid or comet. That matter will blow off the asteroid and provide the "thrust" because you are ejecting matter from the asteroid.

It's more than just the matter in the bomb itself. That's a minor part.

Dr. Gregory Greenman

 

[HowlerMonkey]

Howler Monkey,

NOPE - it's more complicated than that.

The radiation that comes off the bomb will vaporize a bunch of the matter in the asteroid or comet. That matter will blow off the asteroid and provide the "thrust" because you are ejecting matter from the asteroid.

It's more than just the matter in the bomb itself. That's a minor part.

Dr. Gregory Greenman

OK...here is the original post...

Can atomic or nuclear bombs be detonated in space? There is no oxygen and I was wondering in an effort to deter an asteroid if they really could be used - do they need oxygen to work?

For example would they work if you fired one to the moon?

And here is my response...

A nuke creates a blast by superheating matter within it's proximity causing it to expand greatly.

If a nuke is detonated in the near perfect vacuum of space, there isn't anything more than the matter contained within the bomb itself that will expand.

You do see "within it's proximity" in my post above?

My post is pretty clear citing two different scenarios and what would result.

One scenario references matter within the proximity of the nuke and the other references nothing but the bomb itself in a vacuum.


Do you not agree with both of them or did you just post without fully reading my clearly stated post that you quoted in your zeal to skewer?


Later...I'm off the kennedy space center's shuttle facility to do some research and maybe push our current world record further out of reach...back saturday.

 

[Morbius]

E

But as I know the method to explode bomb at asteroid's surface for changing its trajectory now considering as ineffective.

Joe,

100% WRONG. Scientists have been looking at this for almost 2 decades now; and the consensus is that a nuclear weapon is the MOST EFFECTIVE methodology. If the asteroid is small, and we have plenty of time, then we can use a weaker methodology like ramming with a mass. ( Ramming with a mass is not very effective on objects called "rubble piles". Many objects are actually collections of smaller objects with just a loose gravitational cohesion between them. You push on that and you only push a piece of it )

http://www.space.com/8666-nuclear-bombs-save-earth-asteroids.html


But, that nuclear option is most effective in circumstances where there are only a few years notice, said David Morrison, director of the NASA Lunar Science Institute and senior scientist for Astrobiology at NASA's Ames Research Center at Moffett Field, Calif., who has done extensive research on asteroid and comet impact hazards.

"If we have an asteroid that is really large, and we don't have more than a few years notice, nuclear is probably all we can do," Morrison told SPACE.com. "If it's a mile or smaller and we have 10 to 20 years warning, we probably won't go nuclear."


https://str.llnl.gov/Dec09/pdfs/12.09.2.pdf

Dr. Gregory Greenman

 

[Joseph Chikva]

I would agree - but mheslep thought there was something important about who ran the lab.

Why not ask him?

Dr. Gregory Greenman

Pardon, you are right.
But my question also need not an answer as I know that.
Thanks.

 

[Morbius]

Do you not agree with both of them or did you just post without fully reading my clearly stated post that you quoted in your zeal to skewer?

HowlerMonkey,

I read the posts. I understand the posts.

Even in a vacuum, there's more going on than just the expansion of matter.

There is one HELL of a radiation wave expansion that makes the matter expansion look trifling.

I CORRECTED your ERROR

I'm not trying to "skewer".

Why not just be glad that you've now learned something.

Dr. Gregory Greenman

 

[Joseph Chikva]

Joe,

100% WRONG. Scientists have been looking at this for almost 2 decades now; and the consensus is that a nuclear weapon is the MOST EFFECTIVE methodology. If the asteroid is small, and we have plenty of time, then we can use a weaker methodology like ramming with a mass. ( Ramming with a mass is not very effective on objects called "rubble piles". Many objects are actually collections of smaller objects with just a loose gravitational cohesion between them. You push on that and you only push a piece of it )

http://www.space.com/8666-nuclear-bombs-save-earth-asteroids.html


But, that nuclear option is most effective in circumstances where there are only a few years notice, said David Morrison, director of the NASA Lunar Science Institute and senior scientist for Astrobiology at NASA's Ames Research Center at Moffett Field, Calif., who has done extensive research on asteroid and comet impact hazards.

"If we have an asteroid that is really large, and we don't have more than a few years notice, nuclear is probably all we can do," Morrison told SPACE.com. "If it's a mile or smaller and we have 10 to 20 years warning, we probably won't go nuclear."


https://str.llnl.gov/Dec09/pdfs/12.09.2.pdf

Dr. Gregory Greenman

Somewhere I saw also the opposite statements and thought that examples I have quoted here (RAM missile for US NAVY and THAAD for missile defence) confirm my statement.
I never was interested in this challenge in details. Do not know.
May be you are right. But may be not.

 

[Morbius]

Somewhere I saw also the opposite statements and thought that examples I have quoted here (RAM missile for US NAVY and THAAD for missile defence) confirm my statement.
I never was interested in this challenge in details. Do not know.
May be you are right. But may be not.

Joseph,

Until he retired recently, Dr. Dearborn was one of a group of scientists I regularly had lunch with in the cafeteria.

Dr. Dearborn would inform us about all the conferences on this. For example, one of the competing techniques was Rusty Schweigert's "gravity tractor". Dr. Dearborn says he has even convinced Rusty that nuclear weapons are the only thing that can do the real "heavy lifting" when it comes to deflection. Rusty now promotes "gravity tractors" as a way to "fine tune" the new orbit after the nuke has done its work.

Dr. Gregory Greenman

 

[Joseph Chikva]

Joseph,

Until he retired recently, Dr. Dearborn was one of a group of scientists I regularly had lunch with in the cafeteria.

Dr. Dearborn would inform us about all the conferences on this. For example, one of the competing techniques was Rusty Schweigert's "gravity tractor". Dr. Dearborn says he has even convinced Rusty that nuclear weapons are the only thing that can do the real "heavy lifting" when it comes to deflection. Rusty now promotes "gravity tractors" as a way to "fine tune" the new orbit after the nuke has done its work.

Dr. Gregory Greenman

Ok, I have read about Dr. Dearborn's approach. Also I heard something about asteroid threat earlier. Never heard about "gravity tractor".
I am mechanical engineer and so practicist. I see on any theory by side of view how we can use that.
I see one big problem with Dr. Dearborn's approach.
As I understand impossible to explode nuke device (bomb) after touching the target as that as I understand will be destroyed before explosion. So, I see only one way - to explode before touching. And target will absorb only a small part of blast energy via radiation.
Am I correct?

 

[HowlerMonkey]

HowlerMonkey,

I read the posts. I understand the posts.

Even in a vacuum, there's more going on than just the expansion of matter.

There is one HELL of a radiation wave expansion that makes the matter expansion look trifling.

I CORRECTED your ERROR

I'm not trying to "skewer".

Why not just be glad that you've now learned something.

Dr. Gregory Greenman

Your post stated what my earlier post stated and now you are adding an angle not mentioned in your earlier post where you attempted to correct me by restating almost exactly what I had posted.

This is called a spin.

 

[Drakkith]

Ok, I have read about Dr. Dearborn's approach. Also I heard something about asteroid threat earlier. Never heard about "gravity tractor".
I am mechanical engineer and so practicist. I see on any theory by side of view how we can use that.
I see one big problem with Dr. Dearborn's approach.
As I understand impossible to explode nuke device (bomb) after touching the target as that as I understand will be destroyed before explosion. So, I see only one way - to explode before touching. And target will absorb only a small part of blast energy via radiation.
Am I correct?

Even if the warhead was detonated on the surface of the asteroid only about half of the blast would be absorbed by it anyways. Detonating 100 ft above the surface would provide almost the same effect I think.

 

[Joseph Chikva]

Even if the warhead was detonated on the surface of the asteroid only about half of the blast would be absorbed by it anyways. Detonating 100 ft above the surface would provide almost the same effect I think.

I do not know how much – half or less. But sure that much less. Only part of radiation will be absorbed and part will be reflected.

 

[Bob S]

You know, I was thinking the same thing Joseph. I always wondered how effective a nuke would actually be at diverting an asteroid, and if simply ramming something into it a high speed would work better.

Even if the warhead was detonated on the surface of the asteroid only about half of the blast would be absorbed by it anyways. Detonating 100 ft above the surface would provide almost the same effect I think.

Directing energy at an asteroid is useless unless there is momentum transfer to divert its orbit. The nuke has to change the trajectory of, or slow down the asteroid. This requires momentum transfer. Momentum transfer requires ejecting mass, including ablating or knocking off one side of the asteroid. Work out the physics equations of shooting a beebee gun at a baseball. Recall p² = 2ME. You need M (mass) for effective momentum transfer. So the nuke has to blast off a piece off the asteroid.

Bob S

 

[Joseph Chikva]

Directing energy at an asteroid is useless unless there is momentum transfer to divert its orbit. The nuke has to change the trajectory of, or slow down the asteroid. This requires momentum transfer. Momentum transfer requires ejecting mass, including ablating or knocking off one side of the asteroid. Work out the physics equations of shooting a beebee gun at a baseball. Recall p² = 2ME. You need M (mass) for effective momentum transfer. So the nuke has to blast off a piece off the asteroid.

Bob S

That is clear that nuke has to blast off a piece off the asteroid and has to change its trajectory
My questions are simple:
• Inside asteroid or above surface?
• If above how far from surface?
• How here relation between kinetic energy and momentum would help?

 

[Drakkith]

Directing energy at an asteroid is useless unless there is momentum transfer to divert its orbit. The nuke has to change the trajectory of, or slow down the asteroid. This requires momentum transfer. Momentum transfer requires ejecting mass, including ablating or knocking off one side of the asteroid. Work out the physics equations of shooting a beebee gun at a baseball. Recall p² = 2ME. You need M (mass) for effective momentum transfer. So the nuke has to blast off a piece off the asteroid.

Bob S

So you don't think that the vaporization of the surface of the asteroid where the nuke went off is a transfer of momentum?

 

[nikhil khatri]

As everybody said , nuclear reaction is not combustion reaction.A combustion reaction requires oxygen to carryout reaction,in nuclear reaction nucleons participate,either they combine or split into two nucleons which result in release of large amount of energy causing explosion.Sun is one of the best example for it,sun releases energy which is result of nuclear reaction and it also take place in space.

 

[Bob S]

So you don't think that the vaporization of the surface of the asteroid where the nuke went off is a transfer of momentum?

I worked at the Nevada Test Site on nuclear tests in 1958 (before Pres. Eisenhower canceled them), and saw firsthand the surface evaporation by radiation. For a given amount of energy release, moving more mass will cause a greater deflection of an asteroid.

Bob S

 

[mheslep]

mheslep,

Evidently you are not up on current events. Lawrence Livermore and Los Alamos are no longer run by public entities. The US Congress saw fit to PRIVATIZE the nuclear weapons design labs a few years ago.

Lawrence Livermore is now run by an "LLC" - a "limited liability corporation", called "Lawrence Livermore National Security", LLNS (pronounced "lins" ) for short. The major partners in this private company are University of California Regents and Bechtel, along with some junior partners like Texas A&M University:

http://llnsllc.com/

The Dept of Energy is now a "customer"; just like the Pentagon is a "customer" for Boeing, Lockheed, or General Dynamics.

Dr. Gregory Greenman

I would agree - but mheslep thought there was something important about who ran the lab.

Why not ask him?

Dr. Gregory Greenman

Strawman. I made no comment about who ran the lab. The work done there which you referred to earlier as a courtesy is nothing of the kind. LLNL was and is funded by taxpayer dollars, regardless of who manages the lab, at roughly a billion dollars per year.

 

[Joseph Chikva]

I worked at the Nevada Test Site on nuclear tests in 1958 (before Pres. Eisenhower canceled them), and saw firsthand the surface evaporation by radiation. For a given amount of energy release, moving more mass will cause a greater deflection of an asteroid.

Bob S

Very good as I saw nuke explosion only by TV.
Above surface?
Altitude?
Very good if you saw that but has anyone calculated ablation rate? How it dependent on nature of asteroid's matter (iron, ice, etc.)?

 

[DaveC426913]

HowlerMonkey,

I read the posts. I understand the posts.

Even in a vacuum, there's more going on than just the expansion of matter.

There is one HELL of a radiation wave expansion that makes the matter expansion look trifling.

I CORRECTED your ERROR

I'm not trying to "skewer".

Why not just be glad that you've now learned something.

Dr. Gregory Greenman

Morbius, based your responses, you have misunderstood Howler's point. It is doubly uncool to then expect someone to appreciate how much they've "learned" from you.

No need to go over it all again, just dial back on all the fist-pounding wouldja?

100% WRONG.

 

[Drakkith]

I worked at the Nevada Test Site on nuclear tests in 1958 (before Pres. Eisenhower canceled them), and saw firsthand the surface evaporation by radiation. For a given amount of energy release, moving more mass will cause a greater deflection of an asteroid.

Bob S

I don't see what you are getting at here Bob. Are you saying that impacting the asteroid with an equal amount of kinetic energy as a nuke releases in thermal and such is going to cause more of an effect on the asteroid? If so, I agree.

 

[Bob S]

Let's look at deflecting the asteroid 99942 Apophis, a 1,000-foot (320-meter) asteroid that will swing by Earth at a distance of about 19,000 miles (30,000 kilometers) in 2029. In reviewing the Effects of Nuclear Weapons book, S. Glasstone, third edition, published by the U.S. Dept. of Defense, chapter 6 http://nuclearpathways.org/Docs/pdfs/effects/effects6.pdf

The cratering by a 1 kT device is given vs. depth of blast in plots on pages 255 and 256. For a surface blast, the crater diameter is about 60 feet, and depth is 40 feet. Using the scaling laws in the text, a 1 MT device would produce a crater 475 foot diameter and 320 feet deep. Because there is no fallback of ejecta, all of the removed mass will be ejected at high velocity and contribute to momentum transfer, and help deflect the asteroid.

Bob S

 

[Joseph Chikva]

Let's look at deflecting the asteroid 99942 Apophis, a 1,000-foot (320-meter) asteroid that will swing by Earth at a distance of about 19,000 miles (30,000 kilometers) in 2029. In reviewing the Effects of Nuclear Weapons book, S. Glasstone, third edition, published by the U.S. Dept. of Defense, chapter 6 http://nuclearpathways.org/Docs/pdfs/effects/effects6.pdf

The cratering by a 1 kT device is given vs. depth of blast in plots on pages 255 and 256. For a surface blast, the crater diameter is about 60 feet, and depth is 40 feet. Using the scaling laws in the text, a 1 MT device would produce a crater 475 foot diameter and 320 feet deep. Because there is no fallback of ejecta, all of the removed mass will be ejected at high velocity and contribute to momentum transfer, and help deflect the asteroid.

Bob S

I see that this is was investigated. But you did not answered on question:
Above surface?

 

[Drakkith]

Bob I don't see how that relates to the nuke vs high speed kinetic impact question. Perhaps I misunderstood one of your posts?

 

[Joseph Chikva]

Bob I don't see how that relates to the nuke vs high speed kinetic impact question. Perhaps I misunderstood one of your posts?

Simply. Bob states that kinetic hit would be ineffective and nuke blast yes - effective.
But he did not answer embodiment method:
• how to carry nuke charge to asteroid?
• at what altitude or after hit detonation should be? As I am afraid that if after hit, simply nuke device will be destroyed without detonation.
• Or there is planed to do as in Armageddon movie - to send two teams of oil well drillers on two Shuttles

 

[Bob S]

Bob I don't see how that relates to the nuke vs high speed kinetic impact question. Perhaps I misunderstood one of your posts?

Drakkith
The basic question is how a 1MT nuclear device with blast energy but without any kinetic energy could deflect or slow down asteroid 99942 Apophis. The secret is

a) A nuclear device placed on the surface of the asteroid, without drilling, can create a significant crater. For this you need to read chapter 6 of Glasstone's book The Effects of Nuclear Weapons (which gave you the link to in my prior post), and in particular review the plots of the crater size vs. depth of blast on pages 255 and 256. For zero depth of a 1 MT device, the crater is over 300 feet deep. So a lot of mass is ejected.

b) The laws of physics (Newton's laws) require that both energy and momentum are conserved.

OK, now for the details. Assume that the mass of the asteroid is M = 8.6 x 10⁷ tonnes (metric tons), and it has a velocity of 24,000 meters per second. Suppose the ejected mass from the crater is m₁=3.7 x 10⁴ tonnes. So the remaining mass of the asteroid is M-m₁. Further, assume 10% of 1 MT, or 4.7 x 10¹⁴ joules, is converted to kinetic energy of the two masses (E₁+E₂ = E_total).

Suppose the device is placed on the front of the astrroid, so the ejected mass is accelerated, and the remaining mass of the asteroid is decellerated.

Assignment: You have two equations in two unknowns (v₁ and v₂).

½m₁v₁² + ½(M-m₁)v₂² = 4.7 x 10¹⁴ joules

m₁v₁ = -(M-m₁)v₂

How much is the asteroid slowed down? Suppose a 10 MT device were used instead?

Bob S

 

[Bob S]

Simply. Bob states that kinetic hit would be ineffective and nuke blast yes - effective.
But he did not answer embodiment method:
• how to carry nuke charge to asteroid?
• at what altitude or after hit detonation should be? As I am afraid that if after hit, simply nuke device will be destroyed without detonation.
• Or there is planed to do as in Armageddon movie - to send two teams of oil well drillers on two Shuttles

Didn't we put two rover vehicles (Spirit and Opportunity) on the surface of Mars, and 3 astronauts on the surface of the Moon? How hard is it to gently place a 1 MT nuclear device on the surface of an asteroid? The only major interplanetary vehicle landing problems we have had (Mars Polar Lander) was that the landing (retrorocket) parameters were specified (by Lockeed Martin) in English units, and the NASA people used metric units. So what is your concern?

Bob S

 

[DaveC426913]

Didn't we put two rover vehicles (Spirit and Opportunity) on the surface of Mars, and 3 astronauts on the surface of the Moon? How hard is it to gently place a 1 MT nuclear device on the surface of an asteroid? The only major interplanetary vehicle landing problems we have had (Mars Polar Lander) was that the landing (retrorocket) parameters were specified (by Lockeed Martin) in English units, and the NASA people used metric units. So what is your concern?

Bob S

Our failure rate on getting probes to Mars is 50%, and that's a large, stable, relatively non-randomly-rotating target.

 

[Bob S]

Our failure rate on getting probes to Mars is 50%, and that's a large, stable, relatively non-randomly-rotating target.

We are planning a soil-sampling mission to an asteroid in 2016:

http://www.universetoday.com/85953/nasa-selects-osiris-rex-as-first-us-asteroid-sampling-mission/

But the Japanese already did it

http://news.softpedia.com/news/Hayabusa-s-Asteroid-Dust-Finally-Confirmed-166867.shtml

Bob S

 

[mheslep]

Our failure rate on getting probes to Mars is 50%, and that's a large, stable, relatively non-randomly-rotating target.

Except for the '92-93 Observer mission, all the http://en.wikipedia.org/wiki/Exploration_of_Mars#Timeline_of_Mars_exploration" with a successful launch arrived at Mars. I doubt the landing issues that plagued a couple of the missions are relevant to the delivery of a nuclear weapon targeted at an astronomical body with no atmosphere and negligible gravity.

 

[Drakkith]

Bob, I think we were on different pages here lol. I fully agree with you. I was talking about the effectiveness of a nuke vs a high speed impact of an object. I think it is MUCH easier to use a nuke as the amount of energy generated against the asteroid per fuel used to get it there is much greater than shooting something at it. But I was unsure of how effective a nuke would be. Thanks for the posts though, very insightful.

 

[Joseph Chikva]

Didn't we put two rover vehicles (Spirit and Opportunity) on the surface of Mars, and 3 astronauts on the surface of the Moon? How hard is it to gently place a 1 MT nuclear device on the surface of an asteroid? The only major interplanetary vehicle landing problems we have had (Mars Polar Lander) was that the landing (retrorocket) parameters were specified (by Lockeed Martin) in English units, and the NASA people used metric units. So what is your concern?

Bob S

Ok, thanks.
Now I understand your statement.
No interception as usually the approaching enemy aircraft or ballistic missile intercepted (high speed hit – up to 3M and in space higher) but gentle landing on surface.
I understand but think that landing on small target would be a big challenge.
And sure that the momentum which asteroid should acquire as result of nuke blast can be easily acquired also by kinetic hit as well. And it seems me as more easy, rational and reliable way.

 

[DaveC426913]

...targeted at an astronomical body with no atmosphere and negligible gravity.

I think you're making a mistake simplifying it. We're pretty familiar with planetary probe procedures and yet we still have a high screw up rate. We have very littel experience landing on small tumbling bodies whose orbits are not nice, neat and low eccentricity and whose delta v is quite different from Earth's.

I think the ways it's more difficult outnumber the ways it's easier.

 

[Bob S]

...And sure that momentum asteroid should acquire as result of nuke blast can be easily acquired also by kinetic hit as well. And it seems me as more easy, rational and reliable way.

Hi Joseph.
If I work out my kinematics as proposed, the asteroid is slowed down by about 2 meters per second, which is about the minimum needed (corresponds to 39,000 miles per year.).

If a 10 tonne kinematic mass traveling 24,000 meters per second (relative velocity) hits the the 8.7 x 10⁷ tonne asteroid head on, it will slow down the asteroid by only 0.003 meters per second. Not nearly enough. Do you agree?

Bob S

 

[Drakkith]

So...you are saying we need superman then? Or a nuke.

 

[Joseph Chikva]

Hi Joseph.
If I work out my kinematics as proposed, the asteroid is slowed down by about 2 meters per second, which is about the minimum needed (corresponds to 39,000 miles per year.).

If a 10 tonne kinematic mass traveling 24,000 meters per second (relative velocity) hits the the 8.7 x 10⁷ tonne asteroid head on, it will slow down the asteroid by only 0.003 meters per second. Not nearly enough. Do you agree?

Bob S

Hi Bob,
I thought not to slow down asteroid but to give to asteroid some radial (angular) momentum.
As distances (Earth - defending object vs. asteroid - attacking object) are high and dimensions are low, deflecting only on very small angle is required.

 

[mheslep]

I think you're making a mistake simplifying it. We're pretty familiar with planetary probe procedures and yet we still have a high screw up rate.

The record for the US shows otherwise, given a successful launch and given the probe doesn't have to land

We have very littel experience landing on small tumbling bodies whose orbits are not nice, neat and low eccentricity and whose delta v is quite different from Earth's.

Why land a nuclear weapon on the surface, and why would the body's spin rate matter?

 

[DaveC426913]

... given the probe doesn't have to land
Why land a nuclear weapon on the surface, and why would the body's spin rate matter?

I refer you back to Bob S' post, where the question was asked:

How hard is it to gently place a 1 MT nuclear device on the surface of an asteroid?

i.e.: land