New Best Way To Nuke a Short-Notice Asteroid

doug141 writes "A scientist proposes the best way to deal with an asteroid on short notice is to hit it with an impactor, followed by a nuke in the crater. From the article: 'Bong Wie, director of the Asteroid Deflection Research Center at Iowa State University, described the system his team is developing to attendees at the International Space Development Conference in La Jolla, Calif., on May 23. The annual National Space Society gathering attracted hundreds from the space industry around the world. An anti-asteroid spacecraft would deliver a nuclear warhead to destroy an incoming threat before it could reach Earth, Wie said. The two-section spacecraft would consist of a kinetic energy impactor that would separate before arrival and blast a crater in the asteroid. The other half of the spacecraft would carry the nuclear weapon, which would then explode inside the crater after the vehicle impacted.'"

Re:how short is the notice?

[heypete]

If you have the time for it, sure.

As the article says,

A nuclear weapon is the only thing that would work against an asteroid on short notice, Wie added. Other systems designed to divert an asteroid such as tugboats, gravity tractors, solar sails and mass drivers would require 10 or 20 years of advance notice.

It's not really possible to put big rocket motors on an asteroid and push it out of the way, as transporting enough fuel to the asteroid would be unbelievably expensive and likely infeasible with current technology.

Spin spin..

[hantms]

Don't asteroids usually spin? If you blast a crater on one side, then you have some serious aiming to do to hit the crater?

Re:Spin spin..

[AC-x]

Rocket scientists have managed to aim spacecraft to very specific points on spinning bodies before, I'm sure they'll manage.

Re:how short is the notice?

[K. S. Kyosuke]

I believe we're quite capable of telling the composition from remote observation and adjusting the plan accordingly. Also, some M-type asteroids (such as 16 Psyche, to name the most notorious example) do have significant quantities of iron, but I don't think that the majority of even the metallic M-type asteroids are solid iron. "High likelihood" is really an exaggeration.

Sounds great....

[TimO_Florida]

Sounds great until you realize that all asteroids have all kinds of spin. This not only makes hitting the same hole problematic, but even if you did the hole may not be pointed at a direction you want the ejected thrusting gasses to fly....

Soo...

[denzacar]

That is true, but it really doesn't matter all that much if 1.0e9 tons hit you in the form of a few large fragments or a million small ones.

Firing birdshot, buckshot and slugs has exactly the same effect on the target?

You are aware that our planet is continuously peppered by space debris, amounting to something like 10000 to 1000000 tonnes per year? [tulane.edu]
Seen any nuclear winters lately as a result of all those impacts? Or those "toxic nitrogen oxides from the atmosphere heating" you're talking about?

There's an ocean of air above our heads, thousands of kilometers deep, perfectly capable of absorbing all of the impact from the smaller objects - be it kinetic or chemical.
The big objects are a problem cause they make it through those thousands of kilometers largely intact.

Just like with birdshot.
Stand far away, and it won't even scratch the target.
Fire a slug of the same mass, from the same distance and with the same load, and it will go right through the target.

Lawrence Livermore presentation from PDC 2013

[ChrisCampbell47]

Last month, the annual Planetary Defense Conference took place, this time in Flagstaff, Arizona (down the road from Meteor Crater). If you are interested in this topic, you really should take a look at the incredible video archive which has ALL of the presentations -- like 23 hours of them. Seriously, if you really want to dive deep into this subject, imagine me GRABBING YOUR SHOULDERS AND SHAKING YOU and saying loudly right into your face "watch these videos!"

Here is the conference webpage:

http://www.iaaconferences.org/pdc2013/ [iaaconferences.org]

And here is the program, useful for navigating the video archive below:

http://iaaweb.org/iaa/Scientific%20Activity/pdc2013program.pdf [iaaweb.org]

But you really want to go to the videos. Here is the complete archive:

http://www.livestream.com/pdc2013/folder [livestream.com]

Particularly germane to the discussion here, check out this video which includes two presentations:

http://www.livestream.com/pdc2013/video?clipId=pla_48629586-65d2-44c3-a1f3-57c0c259d526 [livestream.com]

At the 1h21m point:
Overview of Collisional-Threat Mitigation Activities at Lawrence Livermore National Laboratory
Paul Miller
(very dry delivery, but very interesting review of nuclear weapon solutions)

At the 1h42m40s point:
GPU Accelerated 3-D Modeling and Simulation of a Blended Kinetic Impact and Nuclear Subsurface Explosion
Brian Kaplinger
(new PhD, on the same team as Dr. Wie, the author mention in the post that leads this thread).

These guys have thought about these problems far harder than you have. You might benefit from listening to them for 20 minutes.

Or, you know, just skip this and resume your underinformed opinionating :)