Shooting Asteroids With Paintballs
October 26, 2012

Who Needs A Nuke? Grab A Paintball Gun And Nail That Asteroid

Lee Rannals for — Your Universe Online

According to a new study, Bruce Willis didn't need a fancy atomic bomb to steer away the asteroid that was aiming for Earth in the movie Armageddon. He could've just been wielding a paintball gun.

An MIT researcher reported that launching a few paintballs from a spacecraft at a relatively close distance to an asteroid could throw the space rock off course.

A pale asteroid would reflect sunlight and, over time, as photons bounce off its surface, could create enough force to push the asteroid in a different direction.

Shooting the asteroid with paintball gun pellets would provide a minimal amount of force that could knock it off course while the paint's reflectivity could eventually do even more damage.

Sung Wook Paek, a graduate student in MIT´s Department of Aeronautics and Astronautics, will be presenting his paper on the research at the International Astronautical Congress in Naples, Italy this month.

Scientists have thought of various methods to try and throw an asteroid off course, whether through launching a projectile at it or detonating a nuclear bomb near it.

The latest paintball strategy builds on previous strategies to just pelt the asteroid like it's a last ditch effort in a game of capture the flag. Paek built on this idea by adding to it the fact that paint could take advantage of solar radiation pressure.

Researchers observed pressure from sunlight could alter the orbits of geosynchronous satellites. Scientists have even come up with ideas to equip spacecraft with sails to catch solar radiation to help push them through orbit.

Paek used the asteroid Apophis for a theoretical test case. This asteroid could come close to Earth in 2029, and then again in 2036.

He determined that five tons of paint would be required to cover the massive asteroid, which has a diameter of 1,480 feet.

For the study, Paek used the asteroid's period of rotation to determine the timing for the distribution of the pellets, launching a first round to over the front of the asteroid. As the pellets hit the asteroid's surface, they would burst and splatter paint five-micrometers deep.

Paek estimates it would take up to 20 years for the cumulative effect of solar radiation pressure to successfully pull the asteroid off its earthbound trajectory.

He said launching pellets with traditional rockets may not be an ideal option, because the violent takeoff may rupture the payload. Instead, he suggests to build the paintballs in space.

Hypothetically, a spacecraft could take off and fill up on paintballs at the International Space Station, then head towards the asteroid for a firing-squad-type delivery.

Paek also said you could fill the pellets with something to help add air drag to slow the asteroid down, or paint it a particular color so it would be easier to track with telescopes on Earth.