When planetary scientist H. Jay Melosh attended a meeting between nuclear weapons designers from the United States and the former Soviet Union in May 1995, he was surprised by how eagerly the ex-Cold Warriors sought to work together against an unlikely but dangerous extraterrestrial threat: asteroids on a collision course with Earth. After Edward Teller, father of the American hydrogen bomb, urged others in the session at Lawrence Livermore National Laboratory to consider building and orbiting large, new, nuclear weapons for planetary protection, some top Russian weaponeers in attendance voiced their support.
“It was a really bizarre thing to see that these weapons designers were willing to work together—to build the biggest bombs ever,” said Melosh, a geophysicist at Purdue University and expert in space impacts who has an asteroid named after him.
Ever since, he has been pushing back against relying on nuclear bombs for the Earth’s defense, arguing that a non-nuclear solution—diverting the trajectory of asteroids by hitting them with battering rams — is both possible and much less dangerous.
But Melosh’s campaign suffered a setback last month when the Obama Administration’s new Energy Secretary, Ernest Moniz, signed an agreement with the Russians that the Americans said could open the door to new collaboration between nuclear weapons scientists on asteroid defense. The topic has been particularly interesting to the Russians since an asteroid the size of a tour-bus exploded high in the skies of Russia’s Chelyabinsk region last February.
President Barack Obama has committed the United States to seeking a world without nuclear weapons, pushed for joint reductions in the U.S. and Russian nuclear arsenals and sought tighter security for nuclear explosives worldwide. “When we fail to pursue peace, then it stays forever beyond our grasp,” Obama said during his landmark speech in Prague in April 2009.
But in recent years, advocates of the use of nuclear weapons to counter space threats have been gaining ground. NASA is spending hundreds of thousands of dollars a year to study the idea, and the U.S. nuclear weapons laboratories are itching to work with the Russians on it. Moreover, weaponeers in both countries are citing the asteroid threat as a reason to hold onto—or to build—very large yield nuclear explosives, which have little terrestrial justification.
There are a few impediments, such as the 1967 Outer Space Treaty signed by 129 countries, which prohibits deploying nuclear weapons in space, and other international treaties that bar nuclear weapons testing anywhere, including in space. Many planetary scientists are leery of the idea and some experts worry that radioactive debris from such a nuclear explosion could itself wreak havoc on Earth.
Outside the world of weaponeers, the idea can evoke humor, as exemplified by the kitschy 1998 Bruce Willis action film “Armageddon,” which shows a team of deep-sea oil drillers landing on an Earth-bound asteroid to implant a nuclear warhead that, at the last moment, separates the rock into neat halves that just miss Earth. Film critic Kenneth Turan called it “sporadically watchable.”