Status Report

NEO News (02/27/04) Planetary Defense Part 3: Societal Issues

By SpaceRef Editor
February 27, 2004
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NEO News (02/27/04) Planetary Defense Part 3: Societal Issues

Orange County, CA, February 23-26 2004

This edition of NEO News concludes my notes from the AIAA Planetary Defense Conference. Focus in the final day was on political and social issues.

Notes by David Morrison

Lee Clark (Rutgers University) provided a keynote talk on Some Human Questions in Planetary Defense. What will people and institutions do if a strike is announced? What will people and institutions do if we predict a strike that will happen far in the future? What will people and institutions do after a strike? Conventional wisdom is that panic is supposed to be a major issue. But we have a robust finding from historical examples of disasters in U.S. that is it very hard to induce panic (e.g., disorganized flight, anti-social behavior). We should jettison “panic” as an issue for NEOs, especially when it is used as an excuse for withholding information. We should also consider that planetary defense might be difficult to deal with internationally, since international competition and conflict are historically just as real as international cooperation. Meanwhile we have challenges in communicating the risk. We need to communicate down, up, and sideways (multiple audiences need multiple messages). These are difficult issues – it may require a strike (by a small NEA, we hope) as a wake-up call before a major mitigation program can be implemented.

In another keynote, Oliver Morton (London) provided historical context. The current interest in impacts represents a real change. Astronomy is the most predictive science but is disassociated from terrestrial affairs. From the 18th century, astronomers have emphasized this distance. Special efforts were made to demystify comets and allay public fear of comets. From the mid ninetieth century, geologists adopted a strictly uniformitarian approach in which catastrophic events were not considered. These ideas have persisted until recently, for example in the New York Times editorial (April 7 1985) which said in the context of the proposed KT impact: “Astronomers should leave to astrologers the task of seeking the cause of earthly events in the stars.” Not until well into the second half of 20th century were either astronomers or geologists willing even to consider possible role of impacts. Science fiction was slightly ahead (Heinline: The Moon is a Harsh Mistress, 1966. Blish & Knight: A Torrent of Faces, 1967. Clarke: Rendezvous with Rama, 1973. Niven & Pournelle: Lucifer’s Hammer, 1977). Only after the Alvarez paper on the KT impact (1980) did these ideas start to become respectable. The KT provided a colorful story about breaking a paradigm, catastrophes, dinosaurs and environmental change. Now we are in a new situation, trying to popularize the idea of the hazard of impacts. As public interest grows it naturally focuses not on what is the greatest danger but on what is the most likely event. Also, the post 9/11 world is concerned with what are very small events by astronomical standards. We should accept this and use it.

Geoff Sommer (RAND) discussed policy issues associated with a NEO mitigation system, using economic policy analysis approaches. A strong case can be made for finding NEAs larger than 1 km, since there is a compelling qualitative incentive for protecting against the end of civilization. However, the issue is more complex for sub-km impacts. Most of the scenarios proposed for this meeting skip the most critical issue – uncertainty about whether the hit will take place. In reality the uncertainty may dominate thinking. We should try to maximize net social benefit. In reality, the purpose of Spaceguard (to retire the risk) is “to reduce dread”. Warning has little social value by itself; indeed the purpose of warning is vitiated without an ability to mitigate. In addition, false warnings (false positives) impose social costs that are not counterweighted by benefits. It is difficult to model the expected NEO alarm rate for any search program (How often will Earth be in an uncertainty ellipse, for how long, etc.) We have not adequately considered the social costs of warning. Note that even a minuscule reduction in percent global GDP resulting from false alarms will swamp any direct benefits in NEO hazard reduction. Possible ways to reduce the costs of false warnings (1) control or manage information (2) restrict surveys (3) demonstrate a mitigation capability. Mitigation systems have positive social value if they increase public confidence. In some cases a technically ineffectual mitigation system can still be very effective (for example, the Patriot missile defense system deployed to Israel in the 1991 Gulf War reduced fear and kept Israel out of the war even though it never successfully intercepted any incoming Iraqi missiles). Even a small start on a mitigation system may be sufficient to negate alarms and will thus will be seen as having positive social and economic value.

John Lodgson (George Washington U.) noted that historically, it takes a long time for new issues to lead to policy action. Do we need to wait for an impact to get public action? Perhaps there is a window of opportunity open for planetary defense through the new U.S. President’s space policy. This NASA policy is much broader than the usual media characterization. It includes strong science and security issues that are related to asteroid defense. But there are no specific asteroid missions in the new NASA Roadmap. We need to market asteroid missions to NASA.

Rusty Schweickart (B612 Foundation) addressed The Real Deflection Dilemma. The deflection dilemma was posed by Carl Sagan a decade ago, when he expressed concern that the defense systems against asteroids would be used so rarely that there is a larger chance of misuse — specifically of an asteroid being deflected toward the earth as a weapon. Schweickart argues that the only precision deflection systems that we are likely to build will not have excess capability – only enough to move the impact point off the earth. The probability of finding a NEA that comes close enough to earth to use as a weapon is just as small as the probability of being hit – of order once in a millennium even for Tunguska class impacts. The real dilemma is associated with controlled deflection, where the impact point is slowly migrated across the earth in the process of being moved off the planet. Who decides on the path, and who can be trusted to implement the deflection? Morrison noted that we could imagine nations sending their own spacecraft to make sure the path did not cross their territory, and even of different groups trying to push the asteroid in different directions.

Evan Seamone (US Army) spoke on The Precautionary Principle as the Law of Planetary Protection. He touched upon a number of legal issues and urged us to learn from existing law concerning obligations to warn of or mitigate dangers on an international level. We need to understand the binding legal obligations influencing planetary protection. Liability can be incurred for either inaction or negligent rescue. The greater the threat, and hence the greater the risk of inaction, the more compelling is the case for taking anticipatory action even if uncertainty remains as to the time and place of the enemy’s attack. The are precedents in the current legal framework for dealing with terrorist threats under Homeland Security Presidential Directive HSPD-5. The HSPD-5 also requires consolidation of major national disaster plans into a single all-discipline all-hazards plan. This makes the Department of Homeland Security the Lead Agency in the U.S. when more than one federal department or agency has become substantially involved, although to date they have shown no interest in the impact hazard.

Mike Belton. Toward a National Program to Remove the Threat of Hazardous NEOs. We need a government champion for new programs such as NEO defense. Public support is not required, but negative public opinion can kill the initiative. Big rare impacts are the greatest risk but they are not a suitable basis for starting a program (times are too long, also requires doing the hardest things first in terms of mitigation). Indefinite waiting or lack of an application surely invites low priority and neglect. His proposed new goal is to reliably mitigate or avoid the most probable kind of impact that can cause serious damage to the social infrastructure in the lifetime of the current population. The expected program cost must be consistent with the expected losses incurred in the impact. Program should be defined for what it is, a technical goal, not science, and he suggests a mitigation budget within NASA of order $10B over the next 25 years.

Pete Worden (BG USAF, on his last week of active duty in the Air Force) spoke on The NEO Threat and Mitigation Issues: An Air Force (barely) Perspective. A wide range of related concerns for the military include meteor storms, small (Tunguska class) NEOs, and civilization threatening NEOs. One major issue is Command and Control (e.g., need for a NEO Warning Center). Also national vs. international, civil vs. military. He finds that it is useful in briefings to emphasize recent events (atmospheric impacts). The focus for planetary defense should be on small objects (10 m to 500 m). We are making progress with the NEO hazard issue, but there is still a giggle factor within the Pentagon. DoD may have interest in dual-use technology but not in assuming responsibility for NEOs. Neither NASA or the DoD seems willing to take on this responsibility.


NEO News (now in its tenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact For additional information, please see the website If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.

SpaceRef staff editor.