A collision between Earth and an asteroid a few kilometers in diameter would release as much energy as the simultaneous detonation of several million nuclear bombs, and with the impact of an asteroid estimated at around 10 km (6.2 miles) in diameter believed to be responsible for wiping out the dinosaurs, numerous strategies have been devised to try and avoid such devastation. The latest idea comes from engineers at Glasgow’s University of Strathclyde who suggest that a swarm of laser-wielding satellites could nudge Earth-bound asteroids off their collision course.
While an Armageddon-style detonation of a nuclear device embedded within an asteroid is fine for the plot of a science fiction movie, many scientists believe a more subtle approach that involves deflecting an asteroid off its course rather than blasting it into radioactive bits and pieces that would rain down on Earth is a preferable and more realistic option. One proposed deflection technique involves using lasers to pulverize the surface of the asteroid, ejecting tiny bits of rock that would act as a propellant and push it onto a different course.
Because a ground-fired laser would have to first have to travel through the atmosphere and would only have limited windows in which to hit the asteroid, some have suggested firing a powerful laser from a single large spacecraft. But the University of Strathclyde engineers believe a fleet of small satellites fitted with solar-powered lasers that would be cooperatively fired at close range would be a better option.
While it was initially feared that the plume of gas a debris that results when the laser breaks down the surface of an asteroid would impinge the spacecraft and contaminate the laser to reduce its effectiveness, Dr Massimiliano Vasile, of Strathclyde’s Department of Mechanical and Aerospace Engineering, says laboratory tests have shown that the level of contamination is lower than expected, allowing the laser to function for longer than first thought.
“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,” said Dr Vasile. “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 and his team are also investigating whether the concept of a flotilla of satellites could also be used to remove space debris.
Source: University of Strathclyde
If something is not done with space debris FAST the space may be lost for generations.(Then they would have to figure out some ground based laser solution to clear up the skies bit by bit).
Finally somebody comes with an idea that sounds practical to me. There is no novelty to blast the junk with lasers - any true and tried Star Wars fan can imagine that (even I did in one of old Gizmag comments on the topic) - but SWARMS of laser-wielding satellites hired for clean up job IS impressive.
They are not weapons but While they could be used as weapons against objects in space the way that Laser beams spread mean that the beam would have defused to much to harm ground objects. At least three countries already have anti-satellite weapons any way. ..............................................................................................................................
First. It does not matter how radioactive you leave the object if it misses earth. Second. The farther away the object is when you apply the force the less velocity change you need to impart to generate a miss. In the Armageddon scenario they should have just thrown as many nukes as soon as they could. Preferably in ground penetrating casings so as much of the energy as possible goes into generating the miss. In the Deep Impact scenario one full yield (100 megatons) Tzar Bomb (AN602 hydrogen bomb) if they launched the rocket within weeks of discovery. I would launch as many bombs as I have heavy lift rockets on hand.
As for the laser swarms and space debris, my idea is even cheaper. Put huge blocks of aerogel in retrograde orbits. Tiny and large objects would lodge in it, be trapped, and slow the block and de-orbit it to burn up with all the chips and chunks.
As for space weapons, I cannot see what the concern is. No rogue nation is going to fire lasers from space down to earth for two reasons. First, as the unattributed comment above points out, the beam will be diffused by the atomosphere, and second, even if such an attack were possible, all satellites are of know origin, so any attack from a satellite will identify the culprit nation and thus make it liable to retalliation.
If a rogue nation wants to nuke the US, it will do it by sailing a merchantman or yacht into the port of New York, say, with the device secreted in the hull somehow. While there would be suspicions as to its origin, who could beat a defence that claimed it must have been attached to the vessel by some terrorists when it was in its last port of call, which might have been in some completely neutral nation? Another route would be across the Canadian border. Some people I know even crossed it by mistake in the backwoods somewhere and were amazed to come across another crossing point, this time marked, that told them they were about to leave the U.S.A. when as far as they knew, they had not even entered it.
Most of the debris generated by the detonation of an impact fused or ground penetrating warhead would receive enough acceleration that they would miss the earth on the other side. More importantly all the matter thrown out of the crater is the reaction mass in a very short lived rocket engine burn and therefor accelerates the large piece to a far greater extent than the near miss detonation approach. If the low probability event happens that some highly radio active 100m sized pieces (or just thousands of tons of dust) do get put an a course that still impacts earth it is a small price to pay for avoiding the extinction event. Also bear in mind that the smaller pieces can be further busted up before entering the atmosphere by normal ICBMs and the radio active dust will be spread widely enough to make it essentially harmless. If the deflection can be made by more gently applied force good but in the case of a dinosaur killer the deflection must be made. ............................................................................................................................
re; funglestrumpet
If you separate your thoughts with a line of periods your comment is still attributed at the bottom of your comments.
Second. There is a matter of scale a hundred car coal train moving a 100MPH is by several thousand orders of magnitude more effected by running into a single mosquito than the earth is by all the rockets we have sent out of orbit. The Tunguska event alone had more effect than all the rockets ever launched.