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When Asteroids Head Toward Earth, We'll Probably Nuke Them

By Wesley Fenlon

The United States and Russia are collaborating on asteroid defense plans based on nuclear weapons, which are by far the preferred tools to blast dangerous rocks out of Earth's path.

"Hypervelocity nuclear interceptor system"--real technology, or James Bond movie plot device? The concept for the hypervelocity nuclear interceptor system is real--more real than Star Wars, Reagan's proposed 1980s defense platform--but it's not about protecting us from the Russians, or other countries that possess nuclear weapons. It's about protecting the planet Earth from asteroids by using nuclear weapons. Yes, just like in Armageddon.

In reality, of course, deep-sea miners won't be touching down on an asteroid to bury a nuclear warhead in its core. That would be ridiculous. Instead, we'll simply launch nuclear warheads at asteroids from here on Earth, relying on massive detonations to blow dangerous space rocks into smaller, less dangerous space rocks, or divert their trajectory out of Earth's orbit. Crazy as nuking asteroids sounds, it's actually the most popular option for dealing with potentially dangerous asteroids, and millions of dollars goes into nuclear asteroid interception every year.

Image credit: NASA/JPL

The Atlantic published a lengthy article on Wednesday from non-profit The Center For Public Integrity, and it's all about our plans to take out asteroids using nuclear weapons. Nuking asteroids isn't just a US initiative--in fact, as far back as 1995, Russian scientists have been eager to collaborate on the idea. Despite the Obama administration's push towards nuclear disarmament, the administration's energy secretary signed an agreement with Russia last month to support collaboration on nuclear asteroid defense.

In 1995, Edward Teller, known as the father of the hydrogen bomb, called for nuclear weapons to be placed in orbit of Earth to protect us from asteroids. That proposal hasn't gained much ground, but of the research that The Atlantic cites, nukes launched from the ground are still, by far, the most supported tool for asteroid defense.

Image credit: NASA/MSFC

The Atlantic writes "Bong Wie, the director of Iowa State University’s Asteroid Deflection Research Center, has a three-year, $600,000 grant from the National Aeronautics and Space Administration to design a 'hypervelocity nuclear interceptor system,' basically an missile-borne, nuclear explosive fitted with a battering ram. The ram would separate from the bomb before impact, gouging a crater in the asteroid so the bomb could then blast it apart.

Wie’s plan is hardly Teller’s grand vision of a space-based nuclear asteroid shield. He proposes using off-the-shelf land-based missiles and explosive warheads currently in the U.S. stockpile to intercept large, city-shattering asteroids that are less than about 10 years from slamming into the Earth, when time is too short to nudge them into a new orbit."

But that's just one approach.

The story continues, "Keith Holsapple, an engineering professor at the University of Washington, said NASA has given him a five-year, $1.25 million research grant to study whether an impact device or a nuclear explosion could deflect an Earth-bound asteroid from its path. He and others say studies have shown these are the only two approaches that could work."

Some scientists prefer the idea of an impact device like a battering ram to deflect asteroids from a collision with Earth. One upside of the non-nuclear approach: if a bomb failed to fully destroy or deflect an asteroid, nuclear debris could make its way to Earth. Another scientist argues that because asteroids can consist of so many different materials, we don't know how they would all react to a nuclear detonation. Some may be knocked off course, while others could fragment into thousands of pieces that stay on course for Earth. Last year Neil deGrasse Tyson proposed using a gravitational tractor to sway an asteroid off course instead of using nukes.

Gravity tractor concept

Currently, space agencies tracking all the gigantic asteroids that would seriously damage Earth say there's nothing that will cross paths with the planet for the next 100 years. But smaller asteroids that we haven't spotted yet could still be damaging, and a new $390 million telescope being built on a Chilean mountain will help spot more potential threats.

Another plan proposed to deter dangerous asteroids: putting the space rocks into big bags.

As exciting as launching nukes into space sounds, we wish NASA was going ahead with one of its alternative plans: putting space rocks into big bags. The Atlantic writes: "In April, the White House budget asked Congress to approve $105 million in seed money for a robotic NASA mission to capture an asteroid in a big bag and drag it to an Earth orbit, so its composition can be studied by astronauts. One aim of this $2.5 billion project, the agency said, would be to figure out how to capture large, rogue, space objects."

Sadly, Congress wasn't so excited about the idea. "The House Committee on Science, Space and Technology voted in July on a NASA authorization bill barring the agency from proceeding," The Atlantic writes. "Its report called NASA’s request 'premature,' saying the agency needs first to complete concept studies, line up international partners and muster more scientific support." Back to the bombs it is.