On January 4, 2007, the Wall Street Journal published an op-ed entitled “A World Free of Nuclear Weapons,” written by an impressive array of statesmen: former secretary of state George Shultz, former secretary of defense William Perry, former secretary of state Henry Kissinger and former senator Sam Nunn of Georgia. In the article the authors worried that the likelihood of international terrorists acquiring nuclear weapons is increasing. They asserted that “unless urgent new actions are taken, the U.S. soon will be compelled to enter a new nuclear era that will be more precarious, psychologically disorienting and economically even more costly than was Cold War deterrence.” Invoking President Ronald Reagan’s call in the 1980s for the abolition of all nuclear weapons, they endorsed “setting the goal of a world free of nuclear weapons and working energetically on the actions required to reach that goal.”
Recently, however, a counterargument has been advanced—by NASA. In 2005 Congress ordered the space agency to analyze the alternatives that it could employ to divert a near-Earth object (NEO)—an asteroid or comet—if one was found to be on a collision course with our planet. Last March, NASA submitted a report entitled “Near-Earth Object Survey and Deflection Analysis of Alternatives,” having first coordinated its response with the White House, the Department of Defense and the Department of Energy. In its report NASA chose to analyze only the highly improbable threat posed by large NEOs, which very rarely strike Earth, in lieu of the more realistic danger of a collision with one of the cohort of smaller NEOs, which are far more numerous. What is more, the report emphasized the effectiveness of nuclear explosions in providing the force to deflect an NEO from a collision course, but it completely neglected the need for precision in such a procedure.
This analysis is seriously flawed. It is important not only to deflect an NEO from a collision course with Earth (primary deflection) but also to avoid knocking the object into a potential return orbit that would cause it to come back a few years later (secondary deflection). Nuclear explosions are not controllable in this way. But a nonnuclear kinetic impact—that is, simply smashing a spacecraft into an NEO—can provide the primary deflection for the vast majority of objects, and a precise secondary deflection, if necessary, could be performed by an accompanying gravity-tractor spacecraft, which would be needed in any event to observe the NEo deflection and its aftermath [see "Gravitational Tractor for Towing Asteroids,” by Edward T. Lu and Stanley G. Love, in Nature; November 10, 2005].
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Ambassador Thomas Graham Jr. served for nearly three decades at the U.S. Arms Control and Disarmament Agency, including a decade and a half as general counsel as well as Acting Director of the agency for most of 1993. In 1993 he led the effort to establish a long-term moratorium on the conduct of nuclear weapons tests. From 1994 to 1996, he was a principal figure in the worldwide effort to successfully support the conclusion of the Comprehensive Test Ban Treaty negotiations. In 1994 President Clinton appointed Thomas Graham as his special representative for arms control, non-proliferation and disarmament, with the rank of Ambassador. From 1993 to 1995 Ambassador Graham led the successful U.S. government effort to indefinitely extend the Nuclear Non-Proliferation Treaty. He has taught at—among others—Stanford University, University of Virginia, Georgetown University, University of Washington and Oregon State University.