Cal Poly professor working on an asteroid-blasting laser
02/27/2013 1:01 PM
02/27/2013 6:46 PM
Who knew that the future of life on Earth might hinge on the calculations of a statistics professor at Cal Poly?
Gary B. Hughes and cohort Phillip M. Lubin, a physicist at UCSB, are working on a solar-powered laser that will melt icy asteroids that are on a collision course with Earth.
Needless to say, their work has taken on added impetus in light of the meteor that smacked Russia earlier this month — the same day that an asteroid the size of half a football field missed Earth by a cosmic eyelash of 17,000 miles.
The system, called DE-STAR (for Directed Energy Solar Targeting of Asteroids and exploRation) is ambitious to the nth degree — but doable, say the two scientists.
“The basic idea,” said Hughes, who’s been working with Lubin for a number of years on balloon payloads and infrared projects, “is to focus an array of lasers on targets far away.” Perhaps as far as 93 million miles, or the distance from Earth to the sun, when fully developed.
“The technology is here; based arrays have been available for years. We’ve used lasers for welding metals for years; the baseline technology is here and is used for other purposes,” he added.
The plan is to build a one-meter square array, developed and tested in the laboratory to optimize the system’s design, and then make the design bigger and bigger.
Once developed in the lab, the next step would be to affix the small array to a balloon and send it up into the stratosphere to check its focus without the interference of the Earth’s atmosphere.
“As we build up and overcome some technical problems, we can then become more serious about an orbiting system,” said Hughes.
According to Lubin, the second phase, or DE-STAR 2, could be built to 100 meters in diameter and start nudging asteroids out of their collision-oriented orbits. DE-STAR 4 would be an orbiter of some 10 kilometers in diameter and, according to calculations by Hughes and Lubin, could harness 1.4 megatons of solar energy each day, which would be enough force to destroy an asteroid 500 meters (or almost 550 yards) across.
“If we had an open checkbook,” says Hughes, “we could have a working system in a year in the lab.” He didn’t say what that cost might be. However, such a scenario would dovetail with the goals of the B612 Foundation.
The foundation is named for the home asteroid of the hero of Antoine de Saint-Exupéry’s “The Little Prince.” B612’s goal is to “significantly alter the orbit of an asteroid in a controlled manner by 2015,” said former astronaut Rusty Schweickart, who’s the public face of the foundation.
“We feel a certain urgency to get on with it so that we can be confident that we’re not going to have a cosmic disaster here for no good, justifiable reason, just because we didn’t get with it,” said Schweickart on the foundation’s website. The foundation’s goal is to place a sun-orbiting telescope that will map those so-far undetected space rocks within the inner solar system.
“This will give us the measurements we need to know in advance of the next asteroid impact, and enable us to actually prevent it,” Schweickart said. “It sounds like science fiction, but we are deadly serious.”
“I loved the movie ‘Armageddon,’” said Hughes, “but it was out of the realm of reality; it’s a Hollywood production. We’ve had several things happen to us that we should be concerned about as real threats.”
Not the least being the recent Russian meteor explosion or the 1908 meteor air burst that leveled thousands of square miles of Siberian forest.
As if vaporizing or altering the trajectory of an asteroid isn’t ambitious enough, Hughes and Lubin envision using the system to determine the composition of asteroids for precious metals, as well as a propulsion system to power space exploration.
Applying what’s known as the Yarkovsky effect, the orbiting array of lasers would focus energy on a craft, pushing it along. If the energy were sufficient enough, it could conceivably propel a 10-ton ship at a velocity near the speed of light, solving the traditional propellant vs. distance conundrum of interstellar travel, Hughes said.
“Light exerts pressure on anything it strikes,” he added. “The amount is phenomenally small. But if exerted consistently over many years, it adds up. What’s more, the shorter the light’s wavelength, the more energy it has, and the more pressure it can exert.” With 1,000 kilograms of light energy beamed at a spacecraft, a trip to Mars would be a 15-day journey, he said.
According to Lubin, “Recent and rapid developments in highly efficient conversion of electrical power to light allow such a scenario now, when just 20 years ago it would not have been realistic to consider.”
“These are not just back-of-the-envelope numbers,” Hughes added. “They are actually based on detailed analysis, through solid calculations, justifying what is possible. And it’s all available under current theory and current technology.”
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