December 16, 2009
Diplomatic Problem With Asteroid Deflection

Former astronaut Rusty Schweickart’s group for promoting the development of asteroid defenses points out a curious problem: While an asteroid would be in the process of getting deflected its aim would shift across the planet Earth. Countries would oppose an asteroid's collision path cross over their territory while it was in the process of being re-aimed to miss Earth entirely.

Schweickart’s group, The B612 Foundation, has advocated a different approach to asteroid deflection, but one that will require an equally difficult international negotiation. They propose to bump or tow an asteroid “in a controlled manner” so that it misses Earth. The only problem is that such a process would take time and as the asteroid’s trajectory changed, it would be “pointed” at different places along a horizontal plane on Earth called the risk corridor.

I think we ought to put more effort into discovering all the asteroids out there. I'd prefer to know when one is going to hit and then have the diplomatic problem of how to deflect it rather than discover it was going to hit 3 days before it got here.

Share |      Randall Parker, 2009 December 16 11:50 PM  Dangers Asteroids


Comments
Brett Bellmore said at December 17, 2009 3:28 AM:

Isn't it the case that asteroid deflection really needs to take place at a time sufficiently distant from the impact that it's projected path is rather vague? It's not like at the beginning of the deflection process, you know with certainty that it's going to hit Italy, and after a week you know with certainty that it's going to blow away Spain. You're still at the "It's going to hit Earth. Somewhere. Probably." level when you're doing the work.

Mike said at December 17, 2009 5:13 AM:

'While an asteroid would be in the process of getting deflected its aim would shift across the planet Earth. Countries would oppose an asteroid's collision path cross over their territory while it was in the process of being re-aimed to miss Earth entirely."

I have heard of utter stupid before, but this takes the cake.

anonyq said at December 17, 2009 5:04 PM:

Why, a dangerous asteroid is probably as destructive as a big nuke. Not something you want to land on your head but nothing to worry about if it happens 500 miles away

Bob Badour said at December 17, 2009 6:17 PM:

anonyq,

A truly dangerous asteroid could make a big nuke look like a bunny fart. No upper limit really exists as far as destructiveness goes.

Stan said at December 17, 2009 9:12 PM:

The projected trajectory of a dangerous body is uncertain to some degree forming a locus or "cone" of possible trajectories. For a dangerous asteroid some fraction of these possible trajectories will intersect the Earth. Lets say that we set a criteria that if there is a 1% probability of the asteroid striking the Earth (the cross section of the Earth intersects 1 in 100 of the possible trajectories) we will take action to deflect the body. At this point no nation in particular is "targeted." The direction of deflection will be determined by the need to move the centroid of the cone of all possible trajectories away from the Earth. In other words we might seek a condition in which instead of the earth intersecting 1 in 100 possible trajectories it only intersects 1 in 10^9 of the possible trajectories.

The benefits of such a move are so obvious that I believe the inevitable objections from crack pot nations will be ignored by the space faring powers.

PacRim Jim said at December 18, 2009 1:37 AM:

Asteroids have been considered as weapons directed from the asteroid belt to anyplace on earth. Better time it right, though, or you'll have a lot of 'splainin' to do.

anonyq said at December 18, 2009 5:52 AM:

Bob,
but the probability of a truly dangerous asteroid is much lower than a locally dangerous asteroid.

Bob Badour said at December 18, 2009 10:04 AM:

anonyq,

Define "locally". Even a locally dangerous asteroid can make a nuke look like a bunny fart. The Tunguska event was on the order of a hydrogen bomb, and it went mostly unnoticed at the time. And yet, even it did damage hundreds of miles away.

The rock itself was only on the order of tens of meters across. Plenty of rocks out there are on the order of thousands or tens of thousands of meters across.

We don't get to choose the size of the rocks that might hit us. At best, we can discover them, but only if we look.

K said at December 18, 2009 3:22 PM:

I sense some fundamental difficulties with asteroid defenses. But I'm certainly amateur in that field so I will just list a few and let others comment.

1) Smaller asteroids can produce a lot of damage but they will be hard to detect. So the surveillance apparatus must be very effective.

2) Large asteroids will be detected but hard or impossible to deflect or destroy (due to mass) as they near Earth. So interception should begin as early as possible. Yet at that time it will be hard to determine if the asteroid will hit Earth at all (as Stan discussed above.)

Which means extremely expensive vehicles may very well be sent on unneeded missions.

3) Still, supposing some large asteroid is going to hit Earth, the interceptors have a very long journey before interception. And once there they may need to make complex maneuvers to gain position before operating.

That doesn't seem more difficult than landing a probe on Mars. But since the asteroid is curving toward Earth I suspect it is.

Randall Parker said at December 18, 2009 8:45 PM:

Bob,

Tunguska only happened in Russia.

anoyq,

You make an excellent point. Diversion of globally damaging asteroids is diplomatically less problematic. Everyone will agree on diverting an asteroid that'll bring on, say, a new ice age. The risks to individual countries in the diversion path will be less important than the total shutdown of photosynthesis.

K,

An asteroid that goes undetected is not a diplomatic issue or other issue in advance of its impact.

Stan,

Some asteroids have low probability of impact. But those who have very high probability do not fit your scenario. Some will be knowable many years in advance.

anonyq said at December 19, 2009 2:26 PM:

Bob,
Smaller asteroids are harder to detect but not much harder than big ones. Distance to the earth is also very important in detection and the much larger number of smaller ones means that the kind of asteroid that is discovered is most likely a smaller one.

Randall, time needed to move a big one is such that that sending more than one "tug" is needed so the probability that an asteroids gets stuck on a target because of malfunction is smaller and "malfunctions" that just happen over say Tehran are difficult to sell.

Bob Badour said at December 19, 2009 3:16 PM:

anonyq,

By your logic, we should do nothing because the vast majority of impacts never have any effect at ground level. In terms of probability, the probability of a Tunguska is tiny compared to the probability of a crumb of rock hitting us.

Much like other chaotic systems, earthquakes and landslides for example, for every 10 Tunguska-sized rocks, we should expect a rock with 10 times the punch. And for every 100 Tunguska-sized rocks, we should expect a rock with 100 times the punch etc. For every Tunguska, we should expect 10 rocks with a tenth the punch, 100 with 1% the punch etc. And truthfully, the vast majority of rocks do burn up in our outer atmosphere.

Tunguska knocked down trees for something like a 16 mile radius. The one that killed the dinosaurs left a dent in the earth with a 250 mile radius. They are both rare events, but similar events are inevitable. It's only a matter of time.

We know a rock like the one that killed the dinosaurs or bigger will hit us. We do not know when.

The question becomes: How long do you plan to be around?

Rich Rostrom said at December 19, 2009 3:35 PM:

There was a similar problem in 1944. The Germans were bombarding London with V-1s and V-2s, and asked their top agent in Britain to provide impact data. He was of course a double agent working for Britain. The British realized at once that by providing bogus data, they could throw off the German aim. They could move the "central point of impact" (CPI) of the V-weapons from central London out into the countryside.

The problem was that in the process, they would move the CPI across some other areas, which would be hit harder. Some higher-up vetoed the project, on the grounds that it was immoral to cause some additional people to die, even if it saved the lives of far more others. (Not Churchill - he was out of the country.) Fortunately the Home Defence Executive went ahead, and Churchill backed them completely when he returned. The deception worked completely, and several thousand lives were saved.

But that decision took a lot of guts. I would not want to be responsible for deciding what to do in a similar case involving an asteroid.

For instance, suppose that the estimated point of impact (EPI) was in central Texas, and the nearest "miss" trajectory was to the SW, over the Pacific. If the diversion works completely, the asteroid misses. If it works partially, the asteroid hits Mexico, or in the Pacific just off shore, devastating the coastline with tsunamis. Mexico might object rather strongly.

Or the EPI was in Israel, and there's no chance of getting it past the Earth. Where does one send it? The Sinai? The northern Arabian desert? The Sahara? The Red Sea?

qed1961 said at December 19, 2009 3:47 PM:

Okay, I suppose I'm missing something, but isn't it obvious to everyone that the only moral course of action is to go mine ALL the asteroids, thereby removing the threat?

Bilgeman said at December 19, 2009 3:48 PM:

"Countries would oppose an asteroid's collision path cross over their territory while it was in the process of being re-aimed to miss Earth entirely."

Wow. an interplanetary case of transnational NIMBY...involving a giant rock from outer space.

This species is doomed.

sherlock said at December 19, 2009 4:29 PM:

I think everyone is missig the point of Brett's comment #1. The only way we will have a chance to deflect an asteroid with presently conceivable technology is if we find it when it is years away from impact. At that point the circular error is very large, and it is simply a case of, at a certain confidence level, does it include the Earth or not. If we find the "-roid" when it is close enough to know where on Earth it will hit, the technical term for our situation is "we're totally screwed".

Unilateralist said at December 19, 2009 5:03 PM:

Have the U.S. build an anti-asteroid defense system unilaterally, and then tell complaining countries to go to hell. Diplomatic problem solved.

Bob Badour said at December 19, 2009 5:22 PM:
The one that killed the dinosaurs left a dent in the earth with a 250 mile radius.

Oops, I measured the wrong thing. It only had a 50 mile radius--not that that changes the point or anything.

Wobots said at December 19, 2009 5:25 PM:

The technology to deflect an object away from the earth is the same technology that can deflect an object to a specific point on the earth. re: "The Moon is a Harsh Mistress" Any political organization would have tremendous clout over anyone else. Like if one country had atomic weapons and no one else did, kinda like 1946.

Michael McNeil said at December 19, 2009 5:39 PM:

I think we ought to put more effort into discovering all the asteroids out there. I'd prefer to know when one is going to hit and then have the diplomatic problem of how to deflect it rather than discover it was going to hit 3 days before it got here.

We can discover all the asteroids that are out there, but locating all the comets that may be falling from near infinity into the solar system is a much more difficult problem (not to speak of figuring out precisely where they're aimed, including exactly accounting for perturbations on their path by other planets as they arrive). As I recall comets make up about 25% of the risk.

philw1776 said at December 19, 2009 6:00 PM:

Problem:
Asteroid threatens not only humanity but all life forms as well. Several oountries object to deflection.
Solution:
1. Fragment asteroid
2. Deflect fragments onto objecting countries
3. Problem solved...permanently

Bill Woods said at December 19, 2009 7:14 PM:

Wobots: "The technology to deflect an object away from the earth is the same technology that can deflect an object to a specific point on the earth."

Not really. If you know that the rock's orbit passes within 10,000 km of the center of the Earth, plus-or-minus 50,000 km, it suffices to shift the orbit 100,000 km in any direction. No precision is required. By contrast, if you want to target a specific point on the Earth, you've got a much harder problem. For starters, your target may be on the side of the planet facing away from the incoming rock.

SMSgt Mac said at December 19, 2009 8:01 PM:

'anonyq' is just making the classic mistake that too many of us do: perceiving probability as the only or dominant factor in estimating 'risk', when risk = probability x consequence. An Earth-killer asteroid 'probability' MAY (and I use 'may' because we have no way of really knowing based upon history) but the consequences are, for all practical purpose, 'infinite' until we get mankind living on more than one rock. This case we don't even need a very complex analysis to get the drift: http://elementsofpower.blogspot.com/2006/11/killer-asteroids-and-risk-management.html

comatus said at December 19, 2009 8:40 PM:

Wow guys, 19 comments in before RAH is quoted. We're developing a problem.
I'm not a trajectory expert (my son is). I only want the popcorn monopoly when this gets to the UN.
Here we are, without Walter Pidgeon and Peter Lorre to save us. What are we gonna do?
"Stay in your homes. Do not panic."

Ed Minchau said at December 19, 2009 11:46 PM:

If the rock's orbital elements are known to a very high precision, then its movements can be projected for centuries in advance. One thing Schweickart has suggested is landing beacons on high Torino scale asteroids like Apophis to get very precise measurements of the orbits. We know that if Apophis passes through a "keyhole" region of space close to Earth on April 13, 2029, then it will definitely hit Earth somewhere along a line extending from around Japan through Mexico and down toward Venezuela on April 13, 2036. If we know the orbital elements of that asteroid to a high precision long before 2029, then it may only take a little nudge in 2022 to make it miss the Earth altogether forever.

Or we could mine it out of existence and turn it into useful stuff that people want to buy.

Randall Parker said at December 20, 2009 2:37 PM:

Ed Minchau,

How much of the material in an asteroid is useful? Could be too low to be worth bothering with. For far less energy than it takes to set up a mining operation on it we could nudge it into a different path. So I do not see how mining is a useful solution.

If we went out to the asteroid belt and examined many asteroids we might find one worth mining. Then again, even if we found an asteroid with lots of useful metals the energy cost of moving those metals somewhere useful might be too high.

Engineer-Poet said at December 22, 2009 9:41 AM:

For some space applications, all mass is about equally useful.  Cosmic-ray shielding is one of them.

Apophis is less than 330 meters in diameter.  Throwing away 0.1% of its mass at 100 m/sec would change its velocity by 0.1 m/sec, which comes to about 3150 km/yr.  If it has a density of 3500 kg/m³, 0.1% of its mass is about 50 million kg; if an electric catapult is used at 50% efficiency, the energy required is about 50 GJ or 137 MWh.  That's about 16 kW for a year.  Over 20 years we should be able to change the path and timing of arrival enough for Apophis to either hit the Moon or slingshot it to deflect it permanently.  In the mean time we could mine several percent of the body itself for other uses.

I think we could manage this.  </sarcasm>

Post a comment
Comments:
Name (not anon or anonymous):
Email Address:
URL:
Remember info?

                       
Go Read More Posts On FuturePundit
Site Traffic Info
The contents of this site are copyright ©