Scientists are building the ultimate science-fiction weapon to deal with asteroids.
A system known as DE-STAR – or Directed Energy System for Targeting of Asteroids and exploRation – will use laser beams to intercept and deflect space rocks.
The concept has been around for several years, but a new paper is now presenting it as a viable solution to ward off dangerous ‘Near Earth Objects’ (NEOs).
The system is the brainchild of UC Santa Barbara physicist Philip Lubin and Gary Hughes, a researcher and professor at California Polytechnic State University, San Luis Obispo.
Another, smaller system, is also being developed, called DE-STARLITE.
Researchers envision this travelling alongside the hazardous asteroid and gradually deflecting it over a longer period of time.
‘Generally speaking, the technology is available today. Qicheng Zhang of the University of California, Santa Barbara, one of the authors of the project, told Astrowatch.net.
‘The main challenge with building a full DE-STAR is the necessary scale to be effective.’
In a paper published this year in the journal Earth and Planetary Astrophysics, Zhang explains how lasers could move or vapourise an asteroid on a collision course with Earth.
He says an orbital planetary defense system could heat asteroids to the point of vapourise.
When they begin ejecting material, a reactionary force will move them out of their existing path.
Astrowatch.net says if DE-STAR had a 330-feet-wide laser array, it could divert asteroids 330 feet in diameter from a distance of about about two million miles.
Meanwhile, a 20 kW version of DE-STARLITE operating for 15 years could deflect an 1,000ft asteroid at a distance of 8,000 miles.
Last year, researchers revealed the system working in the lab – albeit on a smaller scale.
To simulate a laser’s ability to deflect an asteroid, Travis Brashears, a student at the University of California-Berkeley, led a group of students in tests that simulate space conditions.
Using basalt, the composition of which is similar to known asteroids, they directed a laser onto the basalt target until it glowed white hot, a process called laser ablation, which erodes material from the sample.
This changes the object’s mass and produces a ‘rocket engine’ using the asteroid itself as the propellant.
In space, this would be powerful enough to alter its course.
‘What happens is a process called sublimation or vaporization, which turns a solid or liquid into a gas,’ explained Brashears, now a freshman at UC Berkeley who started working in the lab during high school as part of UCSB’s Research Mentorship Program.
‘That gas causes a plume cloud — mass ejection — which generates an opposite and equal reaction or thrust — and that’s what we measure.’
Then the team simulated a spinning asteroid using basalt to determine whether they could slow, stop and change its rotation direction.
They used magnets to spin the basalt and then directed the laser in the opposite direction to slow the rotation.
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