Engineers set their sights on asteroid deflection

March 27, 2012, University of Strathclyde
This is Dr. Massimiliano Vasile. Credit: Graeme Fleming@universityofstrathclyde

Pioneering engineers at the University of Strathclyde in Glasgow are developing an innovative technique based on lasers that could radically change asteroid deflection technology.

The research has unearthed the possibility of using a swarm of relatively small satellites flying in formation and cooperatively firing solar-powered lasers onto an asteroid – this would overcome the difficulties associated with current methods that are focused on large unwieldy spacecraft.

Dr Massimiliano Vasile, of Strathclyde's Department of Mechanical and Aerospace Engineering, is leading the research. He said: "The approach we are developing would involve sending small satellites, capable of flying in formation with the asteroid and firing their lasers targeting the asteroid at close range.

"The use of high power lasers in space for civil and commercial applications is in its infancy and one of the main challenges is to have high power, high efficiency and high beam quality all at the same time.

"The additional problem with asteroid deflection is that when the laser begins to break down the surface of the object, the plume of gas and debris impinges the spacecraft and contaminates the laser. However, our laboratory tests have proven that the level of contamination is less than expected and the laser could continue to function for longer than anticipated."

Just over 100 years ago a 2000-kilometer area of vegetation was destroyed when an object believed to be 30-50 metres in diameter exploded in the skies above Tunguska, Siberia. While the likelihood of an immediate threat from a similar asteroid strike remains low, it is widely recognised that researching preventative measures is of significant importance.

Dr Vasile added: "The Tunguska class of events are expected to occur within a period of a few centuries. Smaller asteroids collide with Earth more frequently and generally burn in the atmosphere although some of them reach the ground or explode at low altitude potentially causing damage to buildings and people.

"We could reduce the threat posed by the potential collision with small to medium size objects using a flotilla of small agile spacecraft each equipped with a highly efficient laser which is much more feasible than a single large spacecraft carrying a multi mega watt. Our system is scalable, a larger asteroid would require adding one or more spacecraft to the flotilla, and intrinsically redundant - if one spacecraft fails the others can continue."

Dr. Vasile is now investigating the use of the same concept to remove space debris. The number of objects in orbit classified as debris is ever-increasing and with no widely accepted solution for their removal. Researchers at the University of Strathclyde believe the space-borne lasers could be used to lower the original orbit of the space debris and reduce the congestion.

Dr Vasile said: "The amount of debris in orbit is such that we might experience a so called Kessler syndrome – this is when the density becomes so high that collisions between objects could cause an exponentially increasing cascade of other collisions.

"While there is significant monitoring in place to keep track of these objects, there is no specific system in place to remove them and our research could be a possible solution.

"A major advantage of using our technique is that the does not have to be fired from the ground. Obviously there are severe restrictions with that process as it has to travel through the atmosphere, has a constrained range of action and can hit the debris only for short arcs."

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deatopmg
1.8 / 5 (10) Mar 27, 2012
"The research has unearthed the possibility of using a swarm of relatively small satellites flying in formation and cooperatively firing solar-powered lasers onto an asteroid this would overcome the difficulties associated with current methods that are focused on large unwieldy spacecraft."

What about the many unwieldy rockets used to put these unwieldy lasar bearing satellites into orbit and the unwieldy maintenance of these satellites for years and years and years?

Who pays for this?
Telekinetic
3.2 / 5 (5) Mar 27, 2012
This is a nifty approach, but I would land a few rocket thrusters onto the asteroid that would automatically screw themselves into the surface and then remotely guide the rock into a harmless trajectory. It's considerably more low tech compared to a flying laser squadron proposed here, but if an asteroid appeared to be heading our way tomorrow - what works is the most elegant of solutions.
antialias_physorg
4.7 / 5 (11) Mar 27, 2012
Who pays for this?

Would you rather have an asteroid impact the Earth? Who's going to pay for THAT?

The swarm of sattelites would be launched only after a suitable target is detected. We're not talking about a solar system-wide network waiting to be activated, here.

I would land a few rocket thrusters onto the asteroid that would automatically screw themselves into the surface

It's hard to screw yourself into a surface securely in (near) zero gravity (what are you going to push against?)

The design with the swarm of sattelites has some essential advantages:
a) It's a swarm (i.e. redundancy vs. failure of individual sattelites)
b) It's non-contact with the asteroid (i.e. no uncertainties about whether you even CAN screw something in - as with a loosely held-together mound of rubble)
c) The energy to move the asteroid is not hauled up there with you (added weight/cost) but comes from the sun.

Sounds like a plan, if you ask me.
Telekinetic
3.2 / 5 (5) Mar 27, 2012
"It's hard to screw yourself into a surface securely in (near) zero gravity (what are you going to push against?)"- antialias

Powder-actuated bolts would be the solution, but once a screw gets a bit of purchase, it will bury itself into the the ground on its own, as any auger would.
antialias_physorg
4.4 / 5 (7) Mar 27, 2012
Powder-actuated bolts would be the solution, but once a screw gets a bit of purchase, it will bury itself into the the ground on its own, as any auger would.

Sure, but with asteroids you don't know whether you're going to get any purchase at all, whether your thrust isn't going to break you off the asteroid again, whether there's so much debris in close orbit around it that you won't be able to land, whether there even is s suitable landing spot...
(and what do you do if it rotates?)

Point being: Landing and/or using thrusters is a very iffy prospect dependent on a lot of unknown factors until you get there. We'd be right foolish if we sent something up there of which we'd only find out after the fact whether it can actually do anything or not.
Telekinetic
1.7 / 5 (3) Mar 27, 2012
"b) It's non-contact with the asteroid (i.e. no uncertainties about whether you even CAN screw something in - as with a loosely held-together mound of rubble)
c) The energy to move the asteroid is not hauled up there with you (added weight/cost) but comes from the sun."- antialias

Unlikely to be loose rubble on the surface, that would require some amount of gravity, wouldn't it? As far as hauling goes, the rover on its way to Mars weighs about a ton, so the weight of my rocket thrusters with fuel may fall within those bounds.
antialias_physorg
3 / 5 (2) Mar 27, 2012
Unlikely to be loose rubble on the surface, that would require some amount of gravity, wouldn't it?

Asteroids do have gravity (just notbery much). And since there is no other force around any kind of dust or debris will stay close.

As far as hauling goes, the rover on its way to Mars weighs about a ton, so the weight of my rocket thrusters with fuel may fall within those bounds.
With a ton of fuel you're not going to move anything anywhere. Certainly not an asteroid that would be a problem upon impact (we're talking asteroids with 30-50 meters diameter here. If you look at the masses involved then a ton of fuel - even for an ion thruster - is a pittance)
TheGhostofOtto1923
3 / 5 (7) Mar 27, 2012
Sure, but with asteroids you don't know whether you're going to get any purchase at all, whether your thrust isn't going to break you off the asteroid again
urm isnt this an issue for engineers? Or whalers? Theyve been harpooning big fish for centuries.
pauljpease
5 / 5 (4) Mar 27, 2012
Sure, but with asteroids you don't know whether you're going to get any purchase at all, whether your thrust isn't going to break you off the asteroid again
urm isnt this an issue for engineers? Or whalers? Theyve been harpooning big fish for centuries.


Yes, they've been doing it for centuries, but with a FAR below 100% success rate. If this is going to help, it needs to work right, the first time, every time. Can't say, "oh, well, we'll get the next one."
AWaB
4 / 5 (1) Mar 27, 2012
This is a great idea. Reasonably cheap and easy, too. Put these things into Lagrange points and other various orbits all around the Earth and moon. Put up solar panel arrays to charge them up. When they're not deflecting anything they can be used to vaporize sizable space garbage when they pass into their firing view.

If they start the fund to build this thing, I'll chip in.
technodiss
not rated yet Mar 27, 2012
the most straight forward approach would be nukes. lots and lots of nukes. we have tens of thousands of them, just waiting to go off. they're already built, armed, and fueled and can be ready to go in five minutes. its said that a nuke wont effect the trajectory of a significantly large asteroid, but ten or fifteen thousand left over from the cold war might just do the trick.
MandoZink
not rated yet Mar 28, 2012
It's hard to screw yourself into a surface securely in (near) zero gravity (what are you going to push against?)

You might use rocket thrusters to press against the asteroid while "screwing it down." You would want to assure correct orientation and timing of the thrust so you don't push the asteroid the wrong way.
Blakut
not rated yet Mar 28, 2012
Maybe put thrusters on it or fire lasers to give the asteroid an increased spin. If it's a pile of rocks, the centrifugal forces would rip it appart at some point.
Telekinetic
1 / 5 (1) Mar 28, 2012
The problem with orbiting laser-firing satellites is it may cause an international stir because of its similarity to Reagan's "Star Wars" program, which provoked the Soviet Union's ire. I doubt that Putin would interpret a move like this much differently. The U.S. could represent this as "non-military", but it would definitely arouse suspicion. Another low-tech approach might be to design the equivalent of an ice breaker ship in space, that would nudge and bump the asteroid with its hardened nose. This design would require the craft to be deft in going forward and in reverse, like a car transmission. Recent work in rocket tech makes it a possibility. The craft could be a drone, although I would volunteer as the pilot.


antialias_physorg
5 / 5 (1) Mar 28, 2012
The advantages of firing lasers on it is twofold

1) you can do it for a very long time.
2) you don't have to carry the energy needed for it with you.

The only other solution that has similar advantages is to float an attractor (heavy sattelite) close to the asteroid (and even that requires constant expenditure of fuel)

The point is not to destroy the asteroid or change the angular momentum (that wouldn't change the path at all). The point is to vaporize tiny parts of the surface and let the resultant gas do the moving for you.
Telekinetic
1 / 5 (2) Mar 28, 2012
The real problem of course is that lasers are pretty much as useless as flashlights at deflecting asteroids.

Another problem is apparently with reading comprehension since the lasers in question are intended to orbit the asteroid not the earth.

"The problem with orbiting laser-firing satellites" - Telephone

It doesn't matter what orbit they're in, if they're up in space, they'll be considered weapons, defensive or not.
TheGhostofOtto1923
3 / 5 (2) Mar 28, 2012
The real problem of course is that lasers are pretty much as useless as flashlights at deflecting asteroids.

Another problem is apparently with reading comprehension since the lasers in question are intended to orbit the asteroid not the earth.

"The problem with orbiting laser-firing satellites" - Telephone

It doesn't matter what orbit they're in, if they're up in space, they'll be considered weapons, defensive or not.
Well sure in the same way that satellites (or planes) can be considered kinetic energy weapons. In exactly the same way.

Take a pill.
Telekinetic
1 / 5 (1) Mar 28, 2012
"Well sure in the same way that satellites (or planes) can be considered kinetic energy weapons. In exactly the same way.

Take a pill."- GhostofOtto

Satellites transmit electronic signals and photographs, and aren't perceived as weapons. Planes are constricted by airspace. You, Ghost, might serve a purpose by sitting on an asteroid and change its course by emitting your hot air.
TheGhostofOtto1923
3 / 5 (2) Mar 28, 2012
"Well sure in the same way that satellites (or planes) can be considered kinetic energy weapons. In exactly the same way.

Take a pill."- GhostofOtto

Satellites transmit electronic signals and photographs, and aren't perceived as weapons. Planes are constricted by airspace. You, Ghost, might serve a purpose by sitting on an asteroid and change its course by emitting your hot air.
Many satellites can be redirected to threaten other satellites or ground targets, much like your solar battle stations. But they are not because reasonable people use them for reasonable purposes.

Further, your solar battle stations will always remain fragile and indefensible targets themselves, as will any country which might decide to use them to warm up ground targets by a few degrees.

Paybacks a bitch, especially with weapons specifically designed for the purpose.
TheGhostofOtto1923
1 / 5 (1) Mar 28, 2012
-But perhaps we should encourage countries like iran to invest a few billion $$, or whatever they use for money over there, on such solar battle stations because they would be far easier to attack than Fordo and it would be good practice to try doing this without creating much orbital debris.

Not a bad idea. Think theyll fall for it? Not as cheap as a supercannon but amadinijad would probably think it was cool-
antialias_physorg
5 / 5 (1) Mar 29, 2012
We're talking about orbit around an asteroid which is way, way, WAY out in space (because this method takes a long time to work). Not orbit around Earth.

And we're also not talking lasers of the size that could destroy anything on the Earth's surface, even if they were in Earth orbit.

Look at the size of probes we can send out into deep space. Now picture the kind of laser we could fit on there (or even on something ten times the size).

But perhaps we should encourage countries like iran to invest a few billion $$, or whatever they use for money over there

They use money that is backed by goods - like everyone else. In their case by the hardest currency currently known: oil.
Telekinetic
1 / 5 (1) Mar 29, 2012
If these limited range and powered craft can disable an ICBM, the Ghost of Khrushchev 1960 will appear at the U.N. pounding his shoe on the podium.
dnatwork
not rated yet Apr 01, 2012
Why not a giant net of carbon nanotube-based fibers, with solar sails (like a parachute) to deflect the thing? It would be kilometers wide, but there's plenty of space out in space.
Graeme
not rated yet Apr 03, 2012
Instead of lasers it could just be a swarm of mirrors heating up a small spot on the surface. This could be much lower cost. Alternately if the surface is loose, a solar powered robot cold throw rocks and dust off the surface into a path that will not hit the earth, or will burn up harmelessly, and via reaction push the main asteroid into a safe orbit.

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