If asteroid 2012 DA14, the 150-foot (45-meter) cosmic rock heading our way, were to hit Earth today, the destruction and the resulting economic impact would be devastating. Thankfully, the asteroid will be “grazing” our planet at a distance of 17,200 miles (27,700 km). But what if we weren’t so lucky? Earth has essentially no asteroid defense system at the moment, but that can be fixed.
Of the near-Earth asteroids larger than 40 meters, 99% have not been mapped, so we have no idea if any are coming straight for us.
Luckily, some people are trying to change this. Among them, the B612 foundation, a non-profit charitable organization composed of scientists and two former NASA astronauts, is proposing to build a space telescope, called Sentinel, that will map asteroids while orbiting the Sun.
Scientists have proposed a number of possible defense systems. Here are our top four picks:
A graduate student from MIT has come up with a pretty cool method of deflecting the next asteroid that comes our way–paint it white. A white asteroid would reflect more sunlight than a dark one, and the photons bouncing off of it would eventually alter its course enough to make it miss Earth. All you would have to do is send a spacecraft close enough to the asteroid so it would be able to launch pellets full of paint powder at the front and the back of the asteroid—and do it 20 years before the asteroid was due to strike. Voilà.
2. Gravity tractors.
Not tractor beams Star Trek-style, but small spacecraft that would deflect the asteroid simply by flying very close to it, so that their gravitational pull teases it ever so slightly off course. A 20-tonne craft could deflect a 200-meter-wide asteroid by riding alongside it for a year. Still slow, but faster than pushing it with sunlight.
Scientist from SpaceWorks engineering have proposed that we send a swarm of robots to drill the asteroid’s surface, sending chunks of it out into space. The recoil from firing off those chunks would eventually change the asteroid’s course. And the best part? These robots are called MADMEN, or Modular Asteroid Deflection Mission Ejector Node spacecraft.
The intense radiation from the blast could vaporize part of the asteroid’s surface, sending it off on a another, more Earth-friendly trajectory. Given that we have the nukes already, this seems like a good option. And most of us would probably prefer they be put to good use somewhere other than on Earth.
Whatever defense system we end up going with won’t mean much if we don’t know what’s out there in the first place. That’s why projects like the B612 foundation’s are so important. The closer an asteroid gets, the more force you need to deflect it. So the further in advance we know about these sorts of threats, the easier it will be to guard against them.