One of the reasons the U.S. is holding on to a few extra nukes, is for their potential use in an asteroid defense system. rw/D. Davis/ Nasa UPI | License Photo

WASHINGTON, Oct. 2 (UPI) -- The Government Accountability Office does its best to keep tabs on all the many moving parts of the federal government, ensuring agencies and programs are spending their money wisely, acting ethically and meeting their performance goals. Suffice to say, they've got their hands full.

Recently, the GAO checked in on the National Nuclear Security Administration (NNSA), which manages the U.S. atomic-weapons arsenal, to gauge their progress on various disarmament goals. The NNSA is supposed to be destroying old nuclear weapons. They're not. But even if they're behind schedule, they're not without excuses.


One of the reasons that a significant supply of uranium-enriched canned subassemblies (CSAs) -- used to arm nuclear warheads -- have yet to be disposed of, is that they're being saved "for potential use in planetary defense against earthbound asteroids."

In a recent report, GAO officials elaborated on the specifics of the disposal delay:

"NNSA officials told us that CSAs associated with a certain warhead indicated as excess in the 2012 Production and Planning Directive are being retained in an indeterminate state pending a senior-level government evaluation of their use in planetary defense against earthbound asteroids."

In recent years, NASA has been ramping up efforts to track near-Earth objects, asteroids that pass through our planet's neighborhood. Astronomers are pretty good at spotting large asteroids and keeping tabs on their whereabouts and future orbiting paths. But our knowledge of smaller space debris is much spottier. Last year, scientists (and everyone else) were completely taken by surprise when a fireball exploded over Chelyabinsk, Russia, rattling walls, shattering windows and sending hundreds to the hospital.

Similar explosions aren't infrequent -- only they happen high up in the atmosphere. Between 2000 and 2013, 26 asteroids hit the Earth's atmosphere and created a sonic disturbance strong enough to set off listening devices intended to monitor nuclear testing around the world.

"There is a popular misconception that asteroid impacts are extraordinarily rare ... that's incorrect," explained former astronaut Ed Lu, founder of the B612 Foundation. As of right now, Lu said, "the only thing preventing a catastrophe from a 'city-killer' sized asteroid has been blind luck."

Of course, tracking asteroids is just half the battle. The other half is destroying one headed for Earth. And that's, reportedly, why the U.S. government is holding on to a few extra nukes -- at least one of the reasons anyway.