Scientists propose destroying asteroids with sun-powered laser array
February 18, 2013
This past Friday was not a good day for asteroid-human relations with asteroid 2012 DA14 passing a mere 27,700 km (17,200 miles) from the Earth just a few hours after a meteor exploded over the Russian city of Chelyabinsk, damaging hundreds of buildings and injuring thousands. Scientists have been quick to point out that both of these events – a meteor exploding over a populated area and a large asteroid passing through Earth's geosynchronous orbit – are quite rare, but when the worst case scenario is the complete annihilation of all life on Earth, it's probably best to be prepared. That's why researchers in California recently proposed DE-STAR – a system which could potentially harness the sun's energy to dissolve wayward space rocks up to ten times larger than 2012 DA14 with a vaporizing laser.
Over the past few years, scientists have been exploring several methods to prevent a cataclysmic asteroid impact on Earth, including launching a spacecraft to study asteroid collisions, arranging a series of satellites to monitor asteroid activity and even deflecting them with paint balls. The looming question remains unanswered though: what's the best way to actually stop an asteroid from striking the Earth?
Philip M. Lubin from UC Santa Barbara and Gary B. Hughes from Polytechnic State University may have an answer with DE-STAR (short for "Directed Energy Solar Targeting of Asteroids and exploRation"). According to the researchers, DE-STAR would consist of satellites designed to gather energy from the sun and convert it into an enormous phased array of lasers powerful enough to disintegrate an asteroid.
It's still all theoretical at this point, but Lubin and Hughes insist the technology for such a system already exists, just not at the correct scale needed to affect a chunk of rock hurtling through space. Their proposal includes rough outlines for DE-STAR models at different diameters, ranging from one about the size of a tabletop to another that would be 10 kilometers (about 6 miles) across. A greater size would mean a more powerful laser.
If you're imagining a laser blast like the one that took out the Death Star in Star Wars though, think again. Hughes and Lubin say that a DE-STAR system 100 meters (about 328 feet) across would just be able to slowly push comets and asteroids out of orbit, away from Earth. A system measuring 10 kilometers (6 miles) in diameter could produce 1.4 megatons of energy per day, enough to completely erode an asteroid measuring 500 meters (about 1640 feet) wide, but it would take about one year.
The researchers also claim the laser array could have other uses besides asteroid protection. For example, DE-STAR could help in simply studying an asteroid's composition and possibly provide a new propulsion system for spacecraft, all while simultaneously defending the Earth from asteroids.
Even if Lubin and Hughes are correct in their calculations, scaling up the proper technology for their proposed DE-STAR system would be no easy task. By their own admission, there are many variables in place that would need to be worked out first, but it's better than having no plan at all. After the events last Friday though, we might start seeing some projects like this receive the support they need to get off the ground.
Source: UC Santa Barbara