On 4 July 2005, NASA collided a projectile with comet Tempel 1. Should a nuclear warhead be used in the future to deflect asteroids? (NASA)

Bad Idea: Blowing Up Asteroids with Nuclear Missiles

27 Jul , 2008 by

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The first thing that comes to mind when someone asks: “How do we deflect a near Earth asteroid?” is “Fire some nuclear missiles at it.” However, this might not be the best course of action. Akin to opening a walnut with a sledgehammer, there might be a better, less messy option. This is what Apollo astronaut Rusty Schweickart thinks at least. Last year, NASA issued a report suggesting they were seriously considering a nuclear option should an asteroid threaten Earth. However, the ex-lunar module pilot believes this decision was manipulated by political pressure, possibly indicating the asteroid threat was being used to speed up nuclear proliferation in space…

When ex-Apollo astronauts express an opinion, people tend to sit up and listen. After all, the astronauts throughout the space race years in the latter half of the 20th Century (from the USA and Russia) were the ultimate explorers, going above and beyond the call of duty, putting their lives on the line for their countries. Several of the retired Apollo astronauts have come forward over the years with their opinions on modern NASA, concerns for the future of the US position in space exploration and their belief in extraterrestrial cover-ups (!). And last Wednesday, during a public lecture in San Francisco, legendary astronaut Rusty Schweickart voiced his opinion about NASA’s decision to use nuclear technology when faced with an asteroid threat.

Schweickart has expressed concern with the possibility of using nuclear weapons to destroy, or deflect Earth-bound asteroids, pointing out there are many other less harmful ways of dealing with the asteroid threat. At the moment he points out that we are completely unprepared to deal with asteroids, but by 2015, we should have developed a gentler means of deflection. Simply blowing asteroids up have many knock-on implications. First and foremost, Schweickart believes that NASA may be open to manipulation to put forward the proliferation of space-based nuclear weapons under the guise of international “safety.” Another problem I can see is blowing up a large piece of rock only to create many smaller (but just as deadly) pieces of rock, doesn’t really extinguish the destructive power of an asteroid on collision course, in fact, it might increase it.

Schweickart’s organization, the B612 Foundation examines other, more subtle ways of deflecting dangerous asteroids are examined (nuclear warheads not included). Decisions such as when to take action, how to better track asteroids and how to deflect them should be an international effort and not one nation’s decision to detonate a nuclear bomb in space.

Source: Wired


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marcellus
Guest
marcellus
July 27, 2008 10:58 PM

I agree with Ethan. Use nuclear weapons to detonate NEAR the asteroid instead of blowing it up.

It would be like using the Orion spaceship idea to slow the rock down and deflect into a harmless orbit.

We have the technology. GO NUKES!
(And by the way, develope less hard core, Marine Corps ways to deal with space rocks.)

Ethan Siegel
Guest
July 27, 2008 7:03 PM
Ian, I don’t understand what the problem with nuclear explosions in space is, even in principle. I addressed these issues here. But at the end of the day, if you want to deflect an asteroid, you need to impart energy to it. You do it all at once at the beginning, and you need less energy than you would at any other time; so a large impact/explosion as early as possible is the smallest amount of energy you could possibly need. A nuclear fusion bomb has no radiation fallout, as it just leaves you with cleanly burned helium. There are debris and fragmentation issues, but that’s really it. Those could be controlled by the location of the explosion,… Read more »
vagueofgodalming
Member
July 28, 2008 2:16 AM
The trouble with Ethan’s argument is that he talks about conservation of energy and momentum, and then just assumes that half the energy of the bomb will go into moving the asteroid. I think the calculation needs to be a lot more careful. What is the momentum of half the photons and debris from the bomb? That tells you how much the asteroid will move. From that you can work out the kinetic energy imparted to the asteroid. The difference between that and the (half-)energy of the bomb presumably goes into heating the asteroid up. I think, ultimately, this is about the second law of thermodynamics: just because you’ve got a lot of energy stored somewhere, doesn’t mean… Read more »
Brad
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Brad
July 27, 2008 8:13 PM

I suggest that if you can access the mass, it might be better to make the nuclear explosion more effective by making a shaped charge out of it. This way you could use a smaller nuke and concentrate _more of_ its energy in a specific direction rather than having it radiate equally in all directions.

Silver Thread
Member
Silver Thread
July 27, 2008 10:02 PM

I like the idea of sending in a rag tag team of roughneck oil drillers to destroy the Asteroid, largely because I am more likely to become a roughneck oil driller than an astronaut.

If we identify and accurately monitor the Asteroids that have the potential to cause problems for us it would be nice to affix an engine to it and nudge it toward a Lagrangian point perhaps where it can essentially be corralled for future mining. Since they are covering a large distance over a long time period, a little energy might suffice, but I’m spitting into the wind.

Ethan Siegel
Guest
July 27, 2008 10:47 PM

Ian,

If you detonate the nuclear weapon right next to the asteroid, half of the emitted photons will collide with the asteroid. By sheer conservation of momentum and energy, half of the emitted energy will go into changing the kinetic energy (and hence momentum) of the asteroid.

I agree with you, though, that the biggest advancements need to be made in tracking so that we can have as much time as possible to figure it out!

Ethan

Tyler Durden
Guest
Tyler Durden
July 27, 2008 11:23 PM
I think the concern with nukes in space lies with * using them on ourselves *. If you allow the foot in the door for weaponizing space, before you know it space colonies, space stations, other ships, and Earthbound targets can all be the victim of space-launched nukes. And a space-launched nuke has the advantage of being undetectable until almost immediately before impact. There’s no ground launch site that spies can be observing, no radar will detect the launch… it will basically just appear above the target when it enters the atmosphere and a few minutes later the target is gone. I have no objection to using nukes to deflect asteroids, but I think it should be a… Read more »
hydrazine
Member
hydrazine
July 27, 2008 11:57 PM

I think there is another problem with the “nuclear option”. Detonating a nuclear charge is a very quick event so you have to get all the mechanics right the first time which means you have to have a *really* good understanding of how the particular asteroid holds together, its gravitational characteristics, the geology etc. With a slow process of deflection you can observe where things are going and possibly modify some parameters. With a nuke you don’t have that luxury. If it doesn’t work the way you intended you’ll have to do it again but this time with even less understood object or collection of objects.

Kind regards,
/Adam

Wizardd
Guest
Wizardd
July 28, 2008 12:29 AM
First of all, radioactivity in space? Come on, space is filled with radiation. Nuclear explosion wouldn’t make any difference. You guys are watching too much movies if you believe that we could attach a engine to asteroid and it would skip hitting Earth. 1.) You should find the asteroid early enough to haul the massive engine and the massive load of fuel. 2.) You have to assemble that complex at the asteroid. 3.) You could try smaller option, but then you would have to find the asteroid even earlier. Same applies on other SCIFI options. And yes, the composition of the asteroid plays huge role when you are planning to plant something on a asteroid. Massive laser is… Read more »
Larloch
Guest
Larloch
July 28, 2008 2:00 AM

I’m really interested in the efficiency of the nuclear missiles in the space. There is no air — nothing to burn (no fireball will blow up), no shock wave, and it won’t create vacuum. So what’s left? Radiation? In space? smile

Dave Ireland
Guest
Dave Ireland
July 28, 2008 5:42 AM

A man cannot defeat a bear with his own strength. So use a gun to shoot it!

Duncan Lunan
Member
July 28, 2008 6:13 AM
There are non-nuclear options. Rusty Schweickart himself apparently favours the gravitational tractor option, though that needs a lot of time. Prof. Colin McInnes of Strathclyde Uni has considered the kinetic option, a scaled-up version of NASA’s Deep Impact, and ESA is planning a similar mission. In the 1980s Gordon Ross of Glasgow School of Art came up with the idea of using a parabolic mirror to create a jet (first publication 1992, Analog October 1994). More recently he’s designed a multi-mirror system called Archimedes. That’s been evaluated by Glasgow Uni Aerospace Dept. in a study financed by ESA, and a detailed paper by Dr. Max Vasile endorsing it was published this month – not on web yet, but… Read more »
geokstr
Member
geokstr
July 28, 2008 6:33 AM

“A man cannot defeat a bear with his own strength.”

UP here near the Arctic Circle, we found it much more efficient to defeat all the Bears at once by using a Favre instead.

smile

John in Missouri
Guest
John in Missouri
July 28, 2008 7:10 AM
I have absolutely no reservations about using nukes in space to deflect an asteroid, but I have to admit that since the first big budget movie came out of Hollywood suggesting we blow an asteroid to smithereens with nukes, a little imp in the back of my mind has whispered softly, “but what about all the detritus left from the explosion. Isn’t it just as dangerous?” I suppose it would depend upon the asteroid. In his famous book “High Frontier” Gerard O’Neill has suggested a method for maneuvering moderately sized asteroids (the size that nukes would have a prayer of moving) and it may be worth considering for something like this. He was a great fan of the… Read more »
neoguru
Member
neoguru
July 28, 2008 8:40 AM

Even if the nuke broke the threat into smaller pieces, it will at least improve the situation. What’s better, being hit by a bullet or shotgun pellets? Niether is pleasant, but you have a much better chance of surviving the shotgun blast.

nedwright
Member
July 28, 2008 9:23 AM
Ethan: your calculation assumes a 100 Megaton bomb which is the correct order of magnitude since the Russians tested a 57 MT bomb. But you can’t put half the energy into kinetic energy of moving the asteroid by exploding it next to the surface. You need to provide momentum p = mv, and you have energy E = 0.5mv^2. So p = sqrt(2mE). Your article assumes m is the mass of the asteroid, but it really will only be the mass of half the bomb, and the deflection will be a million times smaller. We need to use the energy to lift a large mass off the surface of the asteroid at a low velocity to get the… Read more »
cjameshuff
Guest
cjameshuff
July 28, 2008 10:09 AM
Fragments are not necessarily as dangerous. If the fragments are large enough to survive reentry and enough of them hit the Earth, the total damage could be increased. However, if the fragments are small enough that they burn up before hitting ground, lose most of their energy in the upper atmosphere, or if they are dispersed enough to miss the Earth entirely, damage could be greatly reduced. Fragmenting the asteroid could only make things worse, but it could also turn a catastrophic impact into a light show and a few cool summers. In addition, there are things that could be done to minimize the probability of fragmenting the asteroid. Avoiding use of nukes in space is foolishness. We… Read more »
RL
Member
RL
July 28, 2008 12:17 PM
In my opinion, worry about nukes in space being part of a weaponization in space is silly. If a nation the size of China or Russia or the US wanted to launch a quick strike, they’d be better off pulling some submarines to their enemies coast and blasting them. That would be much easier than trying to launch from a space platform which would have a predictable orbit, easily observed and a good target. Since the US has a good fleet of such subs still around, why bother with the expense? It seems to me that many of the opponents of using nukes don’t ever want to admit that they could ever have any use. In terms of… Read more »
RL
Member
RL
July 28, 2008 12:26 PM

Didn’t the American Indians have a big laser that could deflect asteroids? Oh. Wait. That was a Star Trek episode…never mind.

Oh and…

Geokstr: Good one!

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