Asteroid Deflection as a Public Good

I wrote this post over the weekend but given Paul Samuelson's classic contribution to public goods theory and to economic textbooks it seems to also fit today.

In Modern Principles we use asteroid deflection as our example of a public good.  Aside from memorability, the example has two virtues as a teaching tool.  First, asteroid deflection is a true public good for all of humanity which raises free riding issues on a worldwide scale.  Second, asteroid deflection is an example of a public good that is currently provided neither by the market nor by government. Thus the example underlines the fact that public goods are defined by their characteristics–nonexcludability and nonrivalry–and not by whether they are publicly provided, a point of confusion for many students.

The example may seem fanciful but Tyler and I are quite serious about the
importance of asteroid deflection.  Large asteroid hits are rare but if
a large asteroid does hit, billions will be killed.  As a result, sober calculations suggest that the lifetime risk of dying from an asteroid strike is about the same as the risk of dying in a commercial airplane crash.  Yet we spend far less on avoiding the former risk than the latter.

A new report from the National Academy of Sciences discusses efforts to detect near earth objects (NEOs).  Progress is mixed:

The United States is currently the only country with an active, government-sponsored effort to
detect and track potentially hazardous near-Earth objects (NEOs)…
Congress has mandated that NASA detect and track 90 percent of NEOs that are 1 kilometer in diameter
or larger. These objects represent a great potential hazard to life on Earth and could cause global
destruction. NASA is close to accomplishing this goal.

Congress has more recently mandated that by
2020 NASA should detect and track 90 percent of NEOs that are 140 meters in diameter or larger, a
category of objects that is generally recognized to represent a very significant threat to life on Earth if
they strike in or near urban areas….The administration has not requested and Congress has not
appropriated new funds to meet this objective….[Thus] the current near-Earth object surveys cannot meet the goals of the 2005 NASA
Authorization Act…

Moreover, detection is only the first step towards deflection.

As a classroom discussion starter I like the video embedded below.  The jovial attitude of the announcers contrasts amusingly with the topic while subtly illustrating some of our biases in perception yet the video does cover the main points about the worldwide risk, the fact that asteroid deflection is a public good and it hints at the free rider problem.  I do doubt the bit about the riches available from asteroid mining.  Enjoy.


Alex -you are spot on that students confuse public provision or production of a good with it being a public good (for example elementary school education): "But public education is a right that the law guarantees, so no children can be denied it." Thus, I like your example of a public good without (current) provision.

I would point out, though, that while the expected number of deaths from asteroids and commercial airlines might be similar, that comes after our current level of safety management. Without air traffic control, passenger and baggage screening, etc., the number of airline deaths would be much higher. If it is not worth it to spend even more on airline safety, then it may be quite rational to not want to spend anything on asteroid deflection, even if the free rider problem could be solved. Of course, I know nothing about the marginal costs and benefits of further airline safety management spending or of asteroid deflection.

Very good. "Free rider" is an apt term, too, for those of us on Spaceship Earth who refuse to pay taxes to stop the asteroid.

And this would be great for discussing the problem of cooperation without coercion. I'm teaching global warming now in a regulation class, and it is a more complicated example because (a) maybe it's not a real problem, (b) there is no "end of period" before which cooperation must happen, and (c) some countries benefit, some lose from the bad outcome. Next time I teach, I'll start with the asteroid before I move on to the advanced topic.

By the way, a related teaching tool is the recent article on how nice it would be to have a world government restricting each person to one child so as to slow down global warming. . One of my Chinese students had jokingly suggested that in class earlier in the week, suggesting that extra children be killed and the parents fined. That started a good discussion of child taxes, tradeable child permits,and why, legally, such a policy could not be unilaterally imposed by the EPA via the Federal Register administrative process.

Great example, I plan to use it next semester. Not surprisingly students do have a problem in thinking about public goods because the term "public" is used in two different contexts.
I wonder what the political fall out would be if any president, especially Obama, proposed we chip in a $billion or two toward a world-wide asteroid deflection project.

Put the government in charge of asteroid preservation.

They'll be kaput within the decade.

How do you explain public goods theory to someone who drank the Rothbard punch?

(see this dumb view of public goods theory )

Your point about the difference between the characteristics of the good and the means of its provision seems especially difficult on them.

Is this rather like telling a creationist about evolution, something best not attempted at all?

The video is by RT, an english language propaganda outlet for Russian anti-Americanism. Needless to say, this is the Russian version of Al Jazeera. Let's all try a grain of salt before we rely to heavily on the points raised in this piece. TROUBLE AT NASA! THE SKY IS FALLING! AMERICA TO BLAME! Actually most of what you see on RT is pretty funny stuff.

By that definition, searching for aliens is also a public good, but we all still donate our CPU time to SETI.

Jim - You can start by actually explaining things, and not calling other people "dumb" or intoxicated.

Liberal arts -
I spent 4 years in the military, and 1 year volunteering for our civil guard(a volunteer organization of which assists in daily police work).
Believe it or not, people will actually give up much of their time and wealth, if they believe they're making the world a better place by doing so.


I must be a kool-aid drinker because I don't see what's dumb about your link. Afghanistan is a really bad example because there is almost no benefit to the people who wouldn't want to pay.

It's actually the statist Kool-Aid drinkers that seem to have the most trouble to me. Here is how I characterize their reasoning:

1) we want something that doesn't exist.
2) because we want it, it should exist.
3) because it doesn't exist, the government must provide it.
4) because the government provides it then it's a public good.
5) because it's a public good, it must also be a good value.

This is why we have these crazy and yet ubelievably widespread and incredibly well accepted things like taking peoples' land to give to private businesses who provide "public goods." What the statists don't recognize is the public choice aspect where the provision of a lot of asinine things that aren't public goods and are not under-provided.

"If the people really wanted it enough[...]then they would indeed collectively fund it."

To paraphrase former president BJ Clinton (BJ=Bill Jefferson), I guess it depends on what your definition of "enough" is. I do agree though that it is far from automatic, and that framing matters, as do appeals for donations.

The big problem I see is the prisoner's dilemma. If people think it is government's job to do something, then they won't privately fund it for fungibility reasons. If on the other hand they believe that government won't fund it, and someone with a well framed pitch came along, and they wanted it enough....


Agree on the terminology, but the poster also said that if you aren't willing to pay you might be a free rider. It occurred to me probably neither of us should roll out the worst arguments as strawmen.

Government definitely does an outstanding job of collecting taxes and organizing payments, but that cuts both ways because it makes it possible for a lot of idiotic stuff to be funded that have nothing to with public goods and shouldn't be done even if they fit the criteria. At the very least, those things take resources away from actually benefical public goods.

Quote: "As a result, sober calculations suggest that the risk of dying from an asteroid strike is about the same as the risk of dying in a commercial airplane crash."

LMFAO. I stopped reading when I got this far, because clearly you know nothing about asteroids or planes. The risk of being killed by an asteroid is many billions of times less than the risk of dying in a commercial plane crash.

Simply put: quote the number of persons killed by asteroids in the last 100 years (roughly since the invention of flight, not commercial flight - I'm being kind here) which - as we all know is a big fat ZERO. Now, take the number of people who have died in plane crashes.

In what way can you compare the number zero to the huge number of people dying in planes?

This is extreme intellectual dishonesty ... at best!

I think he is pointing out that the odds of a big asteroid hitting in any given 100 year period may be only 1 in a million...but when it hits it will kill EXPECTED VALUE is about the same as the steady stream of airplane deaths.

Funny that some here assume that government running the air traffic control and checking bags is saving lives...I assume that the government itnerference is costing us lives every year. Firstly by normal incompetence and misaligned incentives and secondly by stifling innovation.

"Funny that some here assume that government running the air traffic control and checking bags is saving lives..."

The bag checks may be ridiculous, but nobody has seriously proposed *any* alternative to the government running air traffic control. Not only is it a public good, it's a natural monopoly -- you can't have "competing" air traffic controllers operating in the same airspace. (Can you even imagine it?) Those *need* to be run by the government, otherwise you get charged monopoly prices for them.

Before TSA, there were rent-a-cop private security firms running airport security in a not very impressive fashion.

"Funny that some here assume that government running the air traffic control and checking bags is saving lives...I assume that the government itnerference is costing us lives every year. Firstly by normal incompetence and misaligned incentives and secondly by stifling innovation."

When other people assume, it's funny, but when you assume, it is reasonable? Whatever. As if there isn't normal incompetence in private firms. As for misaligned incentives... OMFG. You might as well have firms who can maximize profits by using contract law against laypeople who get sick.

That being said, the ATC system re-engineering project was/has been a giant mess. Was that the work of government employees or private subcontractors?


Since the "liberals" are as anti-science as the "conservatives", I don't think this is a fair comparison (Though, liberals believe in other unscientific stuff than conservatives). Actually, I doubt that you will get lots of deniers from the right on THE FACT THAT IT IS POSSIBLE. I mean, the reasons you describe are just plain stupid. And you seem to not have studied the art of scepticism or the science pertaining to "Climate Change Sceptics", or you wouldn't have worded it like it belongs on O'Reilly.

Not only is the issue of an Asteroid very different from something like Global Warming, especially when we review time scales. But the problem is, detection of both is similarly far advanced: Not at all. The dramas regarding astroid catastrophe always start with a scientist (or scientific organisation) finding the asteroid and giving everyone at least several days to react. This is likely if we talk about monsterous comets or asteroids with the size of several kilometers. However, to detect objects as big as 100-200 m is almost impossible without advanced detection methods. They are almost invisible to optical methods, they might have the same temperature as space, which makes it even harder.

It is totally unlike global warming, because we have prove that they exist (Asteroid or meteors have already hit Earth and the Moon.) And unlike Global Warming the consequences are easier to understand. Let a big rock fall into a pont and you see the ripples now just extrapolate to planet Earth...

Pretty much everyone (except anarchists) acknowledges that there are some things we’re better off leaving to government. E.g., military, law-enforcement, administration of justice. The point of dispute is where to draw the line. I suppose public goods is one way of doing so, in an economically-rational manner. If nothing else, the more resources expended on non-public goods, the less there is for genuine public goods.

While it is disturbing that someone has chosen to avoid scrutiny of NASA's asteroid deflection options by making them classified, I disagree with Clark Chapman's suggestion of using a spaceship as a "gravity tractor" to deflect an asteroid (7 July, p 19). Fashionable though the "gravity tractor" idea may be with some scientists, it is poorly thought out and fundamentally flawed.
To keep a "gravity tractor" spaceship from falling onto an asteroid, the spaceship's thrusters would have to be pointing towards the asteroid. Unless the thrusters were further apart than the width of the asteroid, their reaction mass would hit the asteroid, pushing it harder than it was being pulled by the gravity of the ship, resulting in a net acceleration in the opposite direction to the pull of the ship's gravity.
Additionally, the "gravity tractor" approach involves a tremendous fuel cost to get a massive spaceship to reach and match orbit with the asteroid, and requires considerable time first to position the spaceship and then to achieve the necessary trajectory change in the asteroid.

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