System would destroy asteroids that threaten Earth

Feb 15, 2013

As an asteroid roughly half as large as a football field—and with energy equal to a large hydrogen bomb—readies for a fly-by of Earth on Friday, two California scientists are unveiling their proposal for a system that could eliminate a threat of this size in an hour. The same system could destroy asteroids 10 times larger than the one known as 2012 DA14 in about a year, with evaporation starting at a distance as far away as the Sun.

UC Santa Barbara physicist and professor Philip M. Lubin, and Gary B. Hughes, a researcher and professor from California Polytechnic State University, San Luis Obispo, conceived DE-STAR, or Directed Energy Solar Targeting of Asteroids an exploRation, as a realistic means of mitigating potential threats posed to the Earth by asteroids and comets.

"We have to come to grips with discussing these issues in a logical and rational way," said Lubin, who began work on DE-STAR a year ago. "We need to be proactive rather than reactive in dealing with threats. Duck and cover is not an option. We can actually do something about it and it's credible to do something. So let's begin along this path. Let's start small and work our way up. There is no need to break the bank to start."

Described as a "directed energy orbital defense system," DE-STAR is designed to harness some of the power of the sun and convert it into a massive phased array of that can destroy, or evaporate, asteroids posing a potential threat to Earth. It is equally capable of changing an 's orbit –– deflecting it away from Earth, or into the Sun –– and may also prove to be a valuable tool for assessing an asteroid's composition, enabling lucrative, rare-element mining. And it's entirely based on current essential technology.

"This system is not some far-out idea from Star Trek," Hughes said. "All the components of this system pretty much exist today. Maybe not quite at the scale that we'd need—scaling up would be the challenge—but the basic elements are all there and ready to go. We just need to put them into a larger system to be effective, and once the system is there, it can do so many things."

The same system has a number of other uses, including aiding in planetary exploration.

In developing the proposal, Lubin and Hughes calculated the requirements and possibilities for DE-STAR systems of several sizes, ranging from a desktop device to one measuring 10 kilometers, or six miles, in diameter. Larger systems were also considered. The larger the system, the greater its capabilities.

For instance, DE-STAR 2—at 100 meters in diameter, about the size of the International Space Station—"could start nudging comets or asteroids out of their orbits," Hughes said. But DE-STAR 4—at 10 kilometers in diameter, about 100 times the size of the ISS –– could deliver 1.4 megatons of energy per day to its target, said Lubin, obliterating an asteroid 500 meters across in one year.

The speed of interplanetary travel—far beyond what is possible with chemical propellant rockets used today—could be increased with this sized system, according to Lubin. It could also power advanced ion drive systems for deep space travel, he said. Able to engage multiple targets and missions at once, DE-STAR 4 "could simultaneously evaporate an asteroid, determine the composition of another, and propel a spacecraft."

Larger still, DE-STAR 6 could enable interstellar travel by functioning as a massive, orbiting power source and propulsion system for spacecraft. It could propel a 10-ton spacecraft at near the speed of light, allowing interstellar exploration to become a reality without waiting for science fiction technology such as "warp drive" to come along, Lubin said.

"Our proposal assumes a combination of baseline technology—where we are today—and where we almost certainly will be in the future, without asking for any miracles," he explained. "We've really tried to temper this with a realistic view of what we can do, and we approached it from that point of view. It does require very careful attention to a number of details, and it does require a will to do so, but it does not require a miracle."

Recent and rapid developments in highly efficient conversion of electrical power to light allow such a scenario now, Lubin said, when just 20 years ago it would not have been realistic to consider.

"These are not just back-of-the-envelope numbers," Hughes concurred. "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.

"There are large asteroids and comets that cross the Earth's orbit, and some very dangerous ones going to hit the Earth eventually," he added. "Many have hit in the past and many will hit in the future. We should feel compelled to do something about the risk. Realistic solutions need to be considered, and this is definitely one of those."

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ScooterG
2.6 / 5 (10) Feb 15, 2013
"It does require very careful attention to a number of details"

This might be the understatement of the decade. Regardless, this is an excellent idea - I hope it gets funded and works as projected.
Skepticus
2.3 / 5 (9) Feb 15, 2013
I hope they don't patent the idea. E.E."Doc" Smith and his Sun Beam Engineers will be mightily pissed.
Modernmystic
3 / 5 (8) Feb 15, 2013
As long as they keep it pointed in the right direction....up. Although I think the atmosphere severely attenuates laser light if I'm not mistaken.

1.4 megatons of energy per day needs some careful administration.

Using it for interstellar, or even intra-system travel is more exciting to me than zapping asteroids.
Q-Star
3 / 5 (5) Feb 15, 2013
As long as they keep it pointed in the right direction....up. Although I think the atmosphere severely attenuates laser light if I'm not mistaken.

1.4 megatons of energy per day needs some careful administration.

Using it for interstellar, or even intra-system travel is more exciting to me than zapping asteroids.


Maybe I missed something, I got the impression that this a space based concept? Is that right? If that is true, a 1.4 megawatt system is cost prohibitive by today's standards.

Anyhoo, I would expect the development of this type of system to first make it's appearance and application in the context of a weapons system. Is DARPA working on anything like this?
Guy_Underbridge
3.7 / 5 (6) Feb 15, 2013
Will it have a 'stun' setting?
alq131
3.3 / 5 (7) Feb 15, 2013
when did megaton become a unit of energy?
s-l-y
5 / 5 (7) Feb 15, 2013
when did megaton become a unit of energy?

A unit of explosive force equal to that of one million metric tons of TNT. Ref.: thefreedictionary.com/megaton
Modernmystic
2.7 / 5 (7) Feb 15, 2013
FTA:

"But DE-STAR 4—at 10 kilometers in diameter, about 100 times the size of the ISS –– could deliver 1.4 megatons"

I wondered about the units of measure too, might be a misprint but there it is. 1.4 megatons is a LOT of energy. Only thermonuclear (not fission) weapons are capable of releasing that kind of energy. Granted it's over a days time, but still...
antialias_physorg
3.4 / 5 (5) Feb 15, 2013
A unit of explosive force equal to that of one million metric tons of TNT

1.4 megatons of TNT are roughly 6E14Joules

The international space station generates 110kW. If my calcs are correct we'd need something roughly 63000 times as large as the ISS to generate that kind of power on a daily basis (no, we are NOT yet technologically capable of operating significant fusion/fission reactors in space). And then we still haven't even figured in losses of the laser (high power lasers are only 10-20% efficient at best) nor beam spread.

I'll agree wit QStar: This does seem a tad economically prohibitive. Especially in the light of other proposals which are FAR cheaper.
Doug_Huffman
2.5 / 5 (8) Feb 15, 2013
Shades of Niven and Pournelle's Moties and their Crazy Eddie Probe's lightsail that can be propulsion or weapon.
Dichotomy
1.2 / 5 (6) Feb 15, 2013
I'm sorry, but do these two phrases really go together?

"There is no need to break the bank to start."

and

Described as a "directed energy orbital defense system,"

I'm sorry but I prefer the concept of incorporating bunker buster technology onto patriot missile batteries, blowing them into small bits in high orbit, and let the atmosphere vaporize them like all the smaller ones that hit us daily.
Q-Star
3.7 / 5 (9) Feb 15, 2013
I'm sorry but I prefer the concept of incorporating bunker buster technology onto patriot missile batteries, blowing them into small bits in high orbit, and let the atmosphere vaporize them like all the smaller ones that hit us daily.


Why do ya think an asteroid of the size of, say, 50 to 100 meters or larger could possibly blown into small bits, small enough not to spread much damage over a wider area?

Relate that to this meteor (probably no more than two meters, a few tons) over Russia today,,,, that is one of those smaller bits ya just created,,, multiply that by thousands, that's what ya'd get by fragmenting. Most of the fragments ya got would actually be much larger, especially if they had high content of iron, nickle, or other hard metals.

I think the best approach is look into developing a means of altering the course rather than destroying it in situ.
antialias_physorg
4 / 5 (4) Feb 15, 2013
I'm sorry but I prefer the concept of incorporating bunker buster technology onto patriot missile batteries,

Bunker busters (and bombs in general, including nuclear ones) are only effective against structures that are basically big air-filled voids with a bit of stone or metal around them.
Against solid stone (like an asteroid) they only make the surface nice and shiny.
holoman
1 / 5 (2) Feb 15, 2013
Let's take this concept a few thousand steps forward, Medusa

http://www.wired....-medusa/
StarGazer2011
1.8 / 5 (6) Feb 15, 2013
nifty idea but not practical i reckon and as other posters have noted there are easier cheaper ways to nudge an asteroid (paint one side white seems to have merit). And I too have wondered when the 'megaton' became a unit of energy; pretty sure it's not SI :)
dan42day
1.3 / 5 (6) Feb 16, 2013


According to OnlineConversion.com, The explosive force of 1.4 megatons is the energy equivelent of 1.627 terawatt hour. Divided by 24 hours, that's about 68 gigawatts continuously over 1 day. According to Wiki, earth's 2008 energy usage averaged about 15 terawatts. So we're talking around half of 1% of the worlds total average power usage, or a little more than the 5 largest power stations on earth combined. That's a lot of energy, but not an unbelievable amount.

Perhaps it would be more economical to tap the energy we produce here on earth and beam it to the laser array in space if the need arises.
Mayday
3 / 5 (4) Feb 16, 2013
If you think this would not be used as a threat/weapon, you really should go back to your history books. I offer two suggestions:
Build it on the far side of the moon, to reduce the likelihood of some future tyrant aiming it at Earth.
Work to make human life on Earth safer from random impacts: encourage people to move away from sea coasts and to avoid clustering in ultra-tight masses(cities). This won't help against an extinction event, but it would help with everything smaller.
Then while you're at it, encourage folks to move away from fault lines and flood plains.
Just sayin'.
cyberCMDR
3.3 / 5 (3) Feb 17, 2013
Then again, pointing such as system at Earth could be a good idea. Use a moderately sized system to heat a small spot on the ocean, where prevailing winds would carry the moisture over drought stricken areas. Or perhaps point it at the ocean a little ways off a polar ice cap, so that the moisture returns to the ground as new snow to replace what has been melting.

One might be able to influence the course of hurricanes, speed the snow melt over areas hit hard by blizzards (using an expanded focal area to not cause damage), or other potentially useful applications. Of course this will never happen, because man has too much of a propensity to apply any available tool to killing off others. As a species, we can't trust ourselves.
GSwift7
1 / 5 (3) Feb 18, 2013
I see their point. There might be merrit in a modular system, but that also comes at a price. To build a significantly large system you would need to launch hundreds of individual satellites. Then you would need a way to keep them in exactly the right place relative to each other. Low Earth orbit would be out of the question, because you would need too much fuel for station-keeping, so you're stuck with expensive higher orbit locations. The cost of the total system and maintaining it, skyrockets (pun intended) exponentially with the size.

Besides, nobody has built a space-based interferrometer yet. You would need to figure out a way to keep the nodes in place relative to each other so you can focus. That's a key tech that doesn't exist yet. This idea is DOA without that.

I like the idea of hitting the asteroid with a penetrator, but not armed with explosive. In stead of an explosive you create a jet of hot material out of the hole. maybe slow nuclear reaction.