How to Deflect an Asteroid

[CraigS]

Ok .. for all those asteroid hunters .. the way to avoid a collision with one is currently being debated … and perhaps, there's a role for a couple of solar sails in the ultimately successful strategy, as well..

Research team casts light on asteroid deflection (http://www.physorg.com/news/2011-01-team-asteroid-deflection.html)



now here comes the politics ..


So, I'd like to ask .. what happens if the asteroid isn't made of material that results in a jet ? The success of this approach would seem to be completely dependent on the assumption that a jet could be generated from the surface material, which would be predicted only by a theory about the composition of asteroids and;

I’m not too sure I like the idea of ‘experimenting with Apophis !!
Leave that sucker alone, I say !

Cheers

[renormalised]

No problem, just dig up Babe Ruth. Stick his cabbage leaf on his head under his hat, hand him a bat and all will be right :):) :P:P

[CraigS]

Yes … I favour the 'more direct' approach !

Y'know .. the one involving missiles, weapons of mass destruction and Bruce W … or better still, Clint and Tommy Lee J !

Don't give that sucker any chances, I say !!

:)

[renormalised]

Yep...way to go :):)

[CraigS]

A little more seriously, surely if a giant solar reflector can create enough heat to deflect the trajectory, a sustained, well directed Fusion bomb campaign should be able to do the same, (if not better), and have the added benefit of reducing the technical risk/complexities.

Wiki list the main avoidance strategies as:

- Nuclear Weapons;
- Kinetic Impact;
- Asteroid gravitational tractor;
- Focused Solar Energy;
- Mass Driver (ejecting mass over time from the Asteroid);
- Conventional Rocket Motor;
- Wrapping the Asteroid in plastic
- Paint it black;
- Release a cloud of steam in front of it;
- Attaching a tether and ballast mass to alter the centre of gravity;
- Laser ablation;
- Magnetic Flux Compression;
- NEONet (I have no idea of what this is).

Take ya pick, folks !

(Perhaps this should be a survey question in the General Chat section ?)

Cheers

[renormalised]

Some of those suggestions are utterly ridiculous and most are beyond our present capabilities...not technically, but practically. In any case, the pollies won't spend the money to find them, let alone try to stop them.

The best bet to stop one would be to develop a powerful plasma or laser based weapon system, but where are they getting the multi-terawatt power generating capacity to power the weapon/s. Then you'd probably have the idiots turning the damn things onto one another.

[Ric]

I've always thought the best way would be to attach a couple of rocket motors and use the thrust to alter it's trajectory.

I suppose all of that assumes our current technology is good enough to get there and carry out the work.

I'm also baffled as to what good wrapping an asteroid in clingwrap is going to do.:confused2:

[renormalised]

Keeps it fresh for when it hits :):P

Don't want a stale and crusty asteroid making a mess, do we :):P

[Ric]

Onya Carl :thumbsup: :rofl: :rofl: :rofl:

[astroron]

A number of small rockets strategically placed could stear it like they do with space craft.
Cheers

[Nortilus]

I guess the first thing to do would be to work out the objects composition. And then come up with a solution from there. If the object was mostly ice, heat it up and turn it to liquid, breaking it up into smaller parts. If it is mostly iron or rock, possibly do the Bruce Willis thing and drill into it and set it with charges. I think trying to push it off course is ultimately the wrong thing to do, as it would possibly still have to be dealt with later on. I reckon break it up into as small as you could, and let the atmosphere do the rest. Im sure we'll get plenty of warning about any NEOs that will impact earth and Im sure the world powers will team up briefly to sort the problem out quickly. Never know, might be just what we need to truly start the road to peace.

[Benno18]

Seems to me that neither party, Russian or American or who-ever-else, wants to take the blame if something goes wrong, yet they both want to be the hero's.
Also neither wants to spend there own money. To me seems both are sitting back and waiting for the other one to do the work. which could become a disaster.

There is always time though......

[higginsdj]

I think most people forget that on the whole, NEO's have a rapid spin rate and none of them are 'the size of texas'. The biggest problem we have is successfully landing something on or just parking something near an NEO. Itokawa and Deep Impact just proved we could crash into one in an uncontrolled fashion. In order to park a bomb off the surface to blow off surface material enough to alter the trajectory in the right direction means pinpoint positioning and timing.

Cheers

[CraigS]

G'Day David;

Glad you could make it to this one ..
:)
What's this 'parking' business ?

Aren't we talking about targetting it with a missile ?

And wasn't Deep Impact a controlled collision ?
:)

Cheers
PS: What was the outcome on your mysterious object discovery ? Did anyone manage to explain the spin rate ?

[OICURMT]

;)

[higginsdj]

Targetting what with a missile? In order to nudge the target you need to 'push' it is a direction. You can't just hit it anywhere otherwise you will get unpredictable results. Park in the sense of place the missile in a predefined position off the surface of the asteroid and explode it. Physically impacting the asteroid itself may not produce the desired result. A single explosion is just going to blast material off the surface. In space there is no concusive effect so prolonged effects will come from irradiation of the surface.

Deep Impact was controlled in the sense that they could hit the target when they wanted to - not target the exact point that they wanted to hit.

My mysterious object - well I have put the results up for publishing. The 'old' camp says the results can be explained by YORP (just). The 'young' camp says YORP can't even come close so look for another mechansim. For me, I have no opinion on either - I'm struggling enough with math and working through the math required for Binary Asteroids. To give you an idea of how far behind I am, I have only just been able to derive;

DsDp = Sqrt(10^(0.4*dm)-1) from dm = 2.5 Log(F/F')

where DsDp = Size ratio, dm is delta magnitude of the eclipse events, F and F' are flux from the Uneclipsed and Eclipsed system.

Trying to get my head around angular momentum now......

Cheers

[space oddity]

Even breaking it into just a few pieces significantly reduces the chance of a cataclysmic explosion.Smaller pieces will lose most of their cosmic velocity as well as ablating a higher percentage of their mass. As long as the pieces hit at below 5km/sec they should not vaporize on impact creating a crater and sun blocking ejecta . If the explosion puts some stresses in to the asteroid, the stresses of atmospheric entry should make it more likely to fragment before impact. At least the moronic argument that multiple projectiles make it more likely to be struck has not been rearing its politically correct head lately.
Quick rough calculation of how many people would receive fatal blows from the meteorite fragments if blown up, assuming everyone is standing outside is a couple of hundred which reduces to only a couple of dozen if helmets are worn on the day as opposed to letting the whole block slam somewhere on the planet or ocean which averaged out for impact over the whole of land/ocean is about 250,000 . Ie, fragmenting reduces fatality risk by a factor of about a thousand and this is with the assumption of standing around outside with no protection.
I say blow it.

[bartman]

Well I think Sanitarium has solved the problem:P

http://www.youtube.com/watch?v=BvO86dHRtFA

Small soft object to kick ( pardon the pun) it out of harms way...

Bartman

[CraigS]

:lol::lol:
Some asteroids are about the same density as a WeetBix, too !
:P:)
Cheers

[OICURMT]

Bwahahaha.... nice... :)

[CraigS]

Hmm;
Cool. I'm really happy that you're discovery is upsetting the theoretical apple cart ! Sounds like fun. Ever since you posted your original query, I've been thinking about it .. haven't come up with anything, but I'm sure the experience of thinking it through will linger with me for some time.
(Thanks for the post, by the way).

:)

I'm pretty sure I have no idea of what your derivation above is all about .. but it seems strangely reminiscent of, and related to, what I just read in the Kepler exoplanets discovery paper, just published. (They're dealing with transit timing variations of the exoplanets eclipsing their stars .. sometimes binary systems, also). Interesting.

Anyway, good luck with the publication, etc.

Cheers

[higginsdj]

Its taking the magnitude flux formula and using it to derive the size ratio of a binary system from the depth of the eclipse events. :) I already had the formula but I just needed to work out where it came from.

Cheers

[Benno18]

whats Brett Lee doing there though???

[CraigS]

Destruction of an asteroid ?? .. Now this is what I'm talkin' about …

Hubble captures Pictures of asteroid collision ! (http://blogs.discovermagazine.com/badastronomy/2010/02/02/hubble-captures-picture-of-asteroid-collision/)

(Image taken around March 2010 by Hubble).

Phil Plait says ..


The larger of the two asteroids making up P/2010 A2, is presently estimated, (post collision), to be 140m across ..



.. one of the Flora family .. probably themselves, remnants of a previous break-up.

Interestingly, the hubblesite release (http://hubblesite.org/newscenter/archive/releases/2010/34/text/) says:



.. and the 'projectile' (if there was one) ..


and the resultants of the (maybe) collision ..


So, we have a theorised collision (probable) .. and empirical evidence of the trajectory of the resulting ejecta … I would think this observation would lead to a model and reasonable predictions for what would happen if a missile impacted such an object ??

(Food for thought .. :) )
Cheers

[snas]

Hmmm, there is a chapter on deflecting asteroids in Phil Plait's book "Death From the Skies" (a cool read!) Now I just have to remember what Phil said we could do. Surely along the lines of things that have been suggested here. Although I don't think he mentioned weet bix! :)
Craig, that asteroid collision is ultra cool!
Stuart

[CraigS]

G'Day Stuart;
Yep. The Max Planck Institute guys published a report on this, (as well), late last year, using the measurements taken by the ESA Rosetta spacecraft, which apparently gave a different viewing geometry of the object.

Their conclusion was even more definitive …



They've worked out all sorts of interesting snippets like the particle size distribution, tail shape, etc.

What a unique observation. Wish we could've actually captured the collision !! Now that would've been a one in a zillion, (or even more), capture that one !!

From their report ..


Cheers