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Scientists propose destroying asteroids with sun-powered laser array

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February 18, 2013

Is a sun-powered space laser the answer to stopping major asteroid impacts? (Photo: Shutte...

Is a sun-powered space laser the answer to stopping major asteroid impacts? (Photo: Shutterstock)

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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.

According to researchers, DE-STAR would consist of satellites designed to gather energy fr...

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

About the Author
Jonathan Fincher Jonathan grew up in Norway, China, and Trinidad before graduating film school and becoming an online writer covering green technology, history and design, as well as contributing to video game news sites like Filefront and 1Up. He currently resides in Texas, where his passions include video games, comics, and boring people who don't want to talk about either of those things.   All articles by Jonathan Fincher
15 Comments

I remember seeing something similar to this in a movie back in the 80's. Didn't work then either.

Rt1583
18th February, 2013 @ 11:27 pm PST

IF.... they did build such a thing, whats to stop them aiming it down at planet earth in the meantime.

but what if they aimed this type of channeled energy at capture plant that could convert the energy to electricity? I know these satellites orbit the earth so there would have to be a series of power stations but it puts a whole new spin on Solar Power.

John Anderson
19th February, 2013 @ 12:01 am PST

And this si how the Death Star proyect begins!

;)

Hugol
19th February, 2013 @ 08:48 am PST

There was a great series of books written by John Ringo. Very well thought out. Really for this idea to reach a point to be viable we would need to be able to loft thousands of these mirrors. Easier to lift a factory into space that can produce them self sufficiently.

As Mr. Anderson pointed out, they could be used against the Earth, or beamed to the planet for energy production. I'd say a huge collector in the middle of a large desert or ocean. Away from population centers.

VoiceofReason
19th February, 2013 @ 09:11 am PST

Several books (Sci-Fi genre mostly) have used such systems as a vehicle for their stories, and almost all to a fault, rely on Very Huge Array's, and in most cases, several of them.

If memory serves me correct, each array would have to be like several square kilometres to provide a decently focused reflection to another target (Receiver or Final Array). The target satellite need not have a Very Large Array to collect, but still needs to be large enough to enable collection from several dispersed Reflector Arrays, and capable of aiming/directing the resultant energy in a particular direction.

The second problem is that sunlight has a mass. That means that the Reflector Array's would need on-board motors to maintain stability and distance to allow accurate aim, so again, another degree of difficulty would be required. Plasma Torch motor perhaps. Requiring refueling once every 10 years? But then, one would need several such arrays, spread out so as to not interfere with manned space flight ("Whups, sorry we cut the Command Module in half...")

What I'm saying is that to provide the "uumpf" that would be needed to even nudge a small meteor or asteroid, would have to be larger than what I believe current technology can sustain. Heck, we don't even have a space-tug capable of going out with several tons of water outside our own gravity well to fuel the position-keeping motors on these Arrays, never mind designing, building, controlling and installing these devices in "deep" space.

To help keep these array's from floating away, install every array in all the L locations around the Earth/Moon. L2, L3, L4 and L5 seem to be the most logical positions, but L3 is just too frakkin' far away, and L2 is kind-of behind the moon, leaving L's 4 and 5. Fortunately, these two Langrangian points just so happen to be the most "steady" points for any installation. However, there is still a range of movement within the L4 and L5 points, so again, station-keeping or constant re-aiming of the mirrors would be constantly required. And it would have to be super accurate

Heh - Classical 3-body libration math.

However, that being said, the benefits of such a system with even 3 Arrays would boost space-based industries a million percent. Access energy could go towards space-based smelting of captured asteroids or even lunar smelters working on low-grav foundry would possibly create enormously strong, yet light building materials for further space development and dropped down "the well" to Earth for exotic materials use.

Just needs the bucks, eh?

Edouin
19th February, 2013 @ 09:48 am PST

"IF.... they did build such a thing, whats to stop them aiming it down at planet earth in the meantime." - John Anderson

That is a possibility, but it also might give it a chance at succeeding. The military's budget is afterall, much larger than NASA's (or any other budget for that matter) And plus with countries like Iran and north korea becoming more belligerent (N.Korea just threatened "final destruction" of S.Korea) It might not be such a bad idea as a precaution. North Korea and Iran want to continue on with their Nuke tests, fine... the U.S. will build the DE[ath]-STAR.... You never Know, it could stop world war 3 just as soon as an asteroid. And hey.... If we can turn it into a spaceship propulsion method, even better.

KushSmoka420
19th February, 2013 @ 11:23 am PST

hmm... 1.4 x 365 = 511

One Falcon Heavy one full yield tzar bomb sounds a lot cheaper and it does not have to be paid for until we see it coming. I betting that meteor defense will be done with rockets and nukes until there is a major industrial presence in space.

re; Edouin

Don't put the solar collector / directed energy emitters in near earth space place then in a solar polar "orbit" inside Venus's orbit but below orbital velocity and use the light sail effect to maintain orbital altitude and steering to keep earth in the defensible area. Also use a tidal stabilization system (Tether a sizable weight closer to the sun at a distance equal to about 3 times the width of the collector/reflector array.) The rest can be accomplished by targeting control.

Slowburn
19th February, 2013 @ 12:05 pm PST

Just get a big magnifying glass.. that will sort it :)

Jamie Carson
19th February, 2013 @ 12:49 pm PST

No weapon potential here :/

MBadgero
19th February, 2013 @ 02:49 pm PST

Note this is proposed by "scientists" - as opposed to "engineers", who are aware photons exhibit mass and Newton's 3rd Law still applies in space.

So the question is; how fast backwards will this giant collector and laser array be going? Light speed, eventually?

Drake Kyzine
19th February, 2013 @ 09:30 pm PST

Slowburn.....rockets and nukes could be more of a disaster. It's hard to know the consistency of an asteroid. A nuke hits an asteroid and doesn't destroy it outright. Now we have radioactive debris and instead of one rock, it's a shotgun blast.

There is no easy solution to this problem. The human race should get out into space. Once we can get some manufacturing capability off the planet, it could be MUCH cheaper to build it out there as opposed to making something then having to lift it.

VoiceofReason
20th February, 2013 @ 08:48 am PST

re; VoiceofReason

Weather it is destroyed or merely deflected does not matter.

The "shotgun blast" of debris that burns up harmlessly in the upper atmosphere is having done enough.

Please don't mention the secondary radiation it will be spread too far and wide to matter.

Had the object that caused the Russian fireball hit a solid 200 pound block of ice in LEO it would not have been noticed.

Slowburn
20th February, 2013 @ 11:45 am PST

re; Drake Kyzine

The thrust from the light sail can be balanced by gravity and the steering used to keep the defense zone centered on earth.

Slowburn
20th February, 2013 @ 11:53 am PST

The obvious place to put such an installation is the Moon.

The Lunar South Pole, specifically.

The Sun never sets there; Tidal forces can be ignored, as the Moon is too big to get pushed out of orbit by mere photons.

Set up the Solar Array for Lunar power generation and Helium Three refining, and it won't just sit there being useless until we suddenly need it.

Then aim the mirrors at the approaching meteorite/comet.

If you need to focus the beam tighter, it's possible to put a re-focusing ring in L3, L4 or L5 orbit; use a percentage of the incoming beam power to maintain station-keeping.

(Solar powered ion drive).

William Carr
20th February, 2013 @ 02:38 pm PST

This would be brilliant for setting up interplanetary light highways all over our solar system. Mars in 3 days, and return trip ditto - no fuel required.

Except zero details on the laser. Obviously no direct solar-pumped, since theyr'e using photovoltaics. Why not?

As for the massive heat dissipation required - what about that, too?

How come these elementary points are not addressed in the article?

Andrew Palfreyman
26th August, 2013 @ 10:38 pm PDT
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