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If a giant asteroid is hurtling toward Earth, who ya gonna call?
Paintballers!
So say the super-geniuses at MIT, who have come up with a novel (and fun) way to stop the destruction of Mother Earth.
Sung Wook Paek, a graduate student in MIT’s Department of Aeronautics and Astronautics, wants to deflect asteroids with a paintball cloud.
Volleys of Paint Powder
If timed just right, Paek posits, pellets full of paint powder, launched in two rounds from a spacecraft at relatively close distance, would cover the front and back of an asteroid, more than doubling its reflectivity, or albedo.
The initial force from the pellets would bump an asteroid off course; over time, the sun’s photons would deflect the asteroid even more.
Paek’s paper detailing his unconventional strategy won the 2012 Move an Asteroid Technical Paper Competition, sponsored by the United Nations’ Space Generation Advisory Council, "which solicits creative solutions to space-related problems from students and young professionals," notes MIT. Paek presented his paper last month at the International Astronautical Congress in Italy.
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MIT News Office |
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A video shows how Sung Wook Paek's award-winning paintball protection system would work.
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The challenge of the competition is to identify novel solutions for safely deflecting a near-Earth object, such as an asteroid.
Bombs and Gravity Tractors
Scientists have proposed a wide variety of methods to avoid an asteroid collision. Some proposals launch a projectile or spacecraft to collide with an incoming asteroid; the European Space Agency is currently investigating such a mission.
Other methods have included detonating a nuclear bomb near an asteroid or equipping spacecraft as “gravity tractors,” using a craft’s gravitational field to pull an asteroid off its path.
Paek’s paintball strategy builds on a solution submitted by last year’s competition winner, who proposed deflecting an asteroid with a cloud of solid pellets. Paek came up with a similar proposal, adding paint to the pellets to take advantage of solar radiation pressure—the force exerted on objects by the sun’s photons.
Researchers have observed that pressure from sunlight can alter the orbits of geosynchronous satellites, while others have proposed equipping spacecraft with sails to catch solar radiation, much like a sailboat catches wind, according to MIT.
27-Gigaton Rock, 5 Tons of Paint
In his proposal, Paek used the asteroid Apophis as a theoretical test case. According to astronomical observations, this 27-gigaton rock may come close to Earth in 2029, and then again in 2036.
Paek determined that five tons of paint would be required to cover the massive asteroid, which has a diameter of 1,480 feet. He used the asteroid’s period of rotation to determine the timing of pellets, launching a first round to cover the front of the asteroid, and firing a second round once the asteroid’s backside is exposed.
As the pellets hit the asteroid’s surface, they would burst apart, splattering the space rock with a fine, five-micrometer layer of paint, MIT explained.
Of course, all of this would require some major advance planning.
Paek estimates that it would take up to 20 years for the cumulative effect of solar radiation pressure to successfully pull the asteroid off its Earthbound trajectory.
Making Paintballs in Space
Paek also says that launching pellets with traditional rockets may not be an ideal option, as the violent takeoff may rupture the payload.
Instead, he envisions paintballs made in space, in ports such as the International Space Station, where a spacecraft could then pick up a couple rounds of pellets to deliver to the asteroid.
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The paintball solution builds on last year's winning idea in the "Move an Asteroid" competition.
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Paek adds that paint isn’t the only substance that such pellets might hold. For instance, the capsules could be filled with aerosols that, when fired at an asteroid, “impart air drag on the incoming asteroid to slow it down,” Paek says.
“Or you could just paint the asteroid so you can track it more easily with telescopes on Earth. So there are other uses for this method.”
Toolbox of Techniques
Lindley Johnson, program manager for NASA’s Near Earth Objects Observation Program, says Paek’s proposal is “an innovative variation” on a method used by others to capitalize on solar radiation pressure. For example, MESSENGER, a spacecraft orbiting Mercury, is equipped with solar sails that propel the craft with solar radiation pressure, reducing the fuel needed to power it.
“It is very important that we develop and test a few deflection techniques sufficiently so that we know we have a viable ‘toolbox’ of deflection capabilities to implement when we inevitably discover an asteroid on an impact trajectory,” Johnson says.
And before you pooh-pooh the whole asteroid danger as overplayed, think again.
The potential for an asteroid collision is a long-term challenge for scientists and engineers, William Ailor, principal engineer for Aerospace Corp. in El Segundo, CA, told MIT.
“These types of analyses are really timely, because this is a problem we’ll have basically forever,” Ailor says. “It’s nice that we’re getting young people thinking about it in detail, and I really applaud that.”
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