NASA May Use Nukes To Defend Earth From Asteroids

In 2013, a 60-foot-wide meteor exploded over Russia, and no one saw it coming. The Chelyabinsk impactor was relatively small by interplanetary standards, but the blast injured about 1,500 people and damaged 7,000 buildings. If a larger rock were headed for Earth, how would we defend ourselves? The short answer is, scientists aren’t really sure, but one solution sounds a lot like the plot from a 1998 Michael Bay movie: just nuke ‘em.

In hopes of averting a space rock calamity, The New York Times reports that NASA has just sealed a deal with the National Nuclear Security Administration—a branch of the Department of Energy that’s “responsible for enhancing national security through the military application of nuclear science.”

Both branches have been independently researching how to use nukes to deflect comets, asteroids and meteors; the new partnership should make it easier for the rocket specialists and nuclear specialists to pool their knowledge. The plan is to characterize potential threats and find ways to deflect them on short notice.

Of particular interest are medium-sized asteroids and comets between 164 and 492 feet in diameter. Large “dinosaur killers” have been pretty well mapped and don’t pose a threat to Earth in the foreseeable future, while small rocks don’t cause catastrophic damage.

Computer simulations suggest that we could successfully blow up a medium-sized space rock. However, the resulting rock fragments could potentially make the situation worse, depending on how far the asteroid is from Earth when it explodes. A better solution might be to use the bomb to deflect the asteroid instead of blowing it to smithereens.

Other (non-nuclear) proposals include gravity tractors, using sunlight to “boil off” parts of the Near Earth Object, and using lasers or high-speed spacecraft to nudge the object off of its collision course with Earth. However, a 2007 NASA study indicated that nuclear solutions may be the best weapon we’ve got when it comes to fighting killer space rocks.

I had this discussion with a few fellow eggheads not long past, and it went something like this:

Let's start with the idea that we can eliminate an inbound impactor, or at the least alter its trajectory.

Destruction would require a massive thermonuclear payload, or multiple payloads with a precision deployment - more firepower than is available. Destruction: OUT.

Turning to deflection, the key is finding the Intercept Point (IP) where the force applied would cause the trajectory to change just enough to either miss the planet, or skim the atmosphere to either break up or mitigate the impact.

The IP has to be far enough out where available weaponry can make the required course change. And there's problem: we don't have that many launch vehicles to get the payloads there.

Most ICBMs are suborbital boosters, meant to get their payloads in low orbit, then gravity takes over and they reach their targets. Therefore, using Titans or SS-23's would mean the IP has to be in Earth orbit - most likely not getting an IP that would achieve the result.

If a more distant IP is needed, then the only boosters capable of the task would be Delta-3 rockets or Energiya's, if operational. Even then, the IP would be in near geosynchronous orbit (approx. 25K miles) - and that's cutting it close.

Targeting the inbound itself would not be difficult - the missiles could be radar-guided to IP, or the IP calculated into the guidance package.

And then, there's the golden problem: DETECTION: All of these schemes will work, ONLY IF the impactor was detected out far enough for the boosters to be readied, the payloads loaded, the targeting systems aligned, and THEN comes the risks of success - even IF the impactor is neutralized, we still have meteorrites raining down on the planet, PLUS the EMP generated from detonating multiple weapons in Earth orbit.

An interesting exercise.

Turning a few small rocks into a bunch of little bitty rocks.

Large rock is following a trajectory defined by gravity.

Bomb smashes rock to iddy bitty pieces.

Pieces continue to follow former trajectory as a spreading "cloud" of rubble.

Earth get hit by a "shotgun" blast.

Better idea to change trajectory and steer rock away from Earth orbital path.

Regards,
GtG

Two incidents come to mind, recently...

First the Chelabinsk fireball from 2013 - NONE of the self-proclaimed astronomy experts saw it until it hit the atmosphere.

Second, a rock came down in the Sudan recently, and the same people were high-fiveing each other because they actually detected the inbound - NINETEEN HOURS before it hit.

Doesn’t lend much credence to the idea of “THERE’S NOTHING OUT THERE, YOU’RE STUPID!!!”

Because... how would they know?

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