From IOL Technology in NZ:

Reports in the US suggest that ideas either on the drawing board, or else already in development, include killer satellites that could destroy an enemy’s satellites, a Common Aero Vehicle (CAV) that could swoop with hypersonic speed up to 3000 miles to attack a target, Hyper-Velocity Rod Bundles which would fire tungsten bars weighing 100kg from a permanently orbiting platform - and even a space-based laser that uses mirrors to direct the sun’s rays against ground targets.

I talked about rods earlier… also, I’m starting to get worried about trends in the direction of solar weapons, i.e., weapons that use the sun’s power to incinerate things. These have a lot of potential, and are potentially much stronger than nuclear weapons. It’s one of three superweapons that should be banned forever - nuclear (ICBMs), solar (beams), and kinetic weapons (meteors), with ascending severity. Following is a (rough) excerpt from a work in progress that reviews twelve major existential threats in detail, “Catastrophic Technological Risk”:

Solar weapons are a serious concern because there is both the tendency to underestimate what the world’s superpowers will be capable of within this area in the next 20-50 years, and the general feel-good sensation associated with solar power that makes it seem so utterly harmless.

For this risk, the biggest worry is the threat of an arms race between two or more powerful countries. Bigger, faster weapons and shields precipitate the creation of newer, bigger, and faster weapons and shields, still followed by weapons and shields that are yet bigger and faster, and so on. The only natural endpoints of such a world-endangering endeavor would be victory for a single country, which would probably consist of the creation of a system capable of instantaneously immobilizing an entire enemy nation, or an explosive, all-out war, which may include nuclear weapons, but would be post-nuclear in its scope and severity.

Solar weapons are especially attractive to militaries because they would trump nuclear weapons. Intercontinental ballistic missiles (ICBMs) are physical objects that must propel themselves to their destination – directed energy moves at the speed of light, and requires sophisticated active shielding to effectively protect against. At the highest intensities, shielding may be impossible, even in principle. This gives attackers a first strike advantage on the solar battlefield.

One might say that solar energy and directed energy are not the same thing, and that what I’m actually talking about is directed energy, not ‘solar weapons’ per se. But there is a reason I am talking about solar weapons specifically. Fossil fuels could not possibly produce the output necessary to power the weapons that are being foreseen here – it would simply be too expensive. Nuclear is definitely a possibility, but it’s easier to talk about ‘solar weapons’ than ‘nuclear-powered electromagnetic weapons’, so just consider the latter included in this category of risk.

In the past, directed energy has been plagued by various development problems. Most weapons only work when skies are relatively clear, though newer models attempt to be more flexible. Weapons of the future will circumvent the limitations of the past. The most powerful solar weapons will push aside air molecules before sending the primary energy arc down the channel, and this will all happen within fractions of a second, even when the target is dozens of km away. Infrared, auditory, electrical, laser, and particle-based superweapons are all conceivable. ‘Artificial lightning’ will be available to the military commanders of the future. This is not speculative – hundreds of millions of dollars went towards directed energy research in 2005, and dozens of projects are either on the drawing board or already in development.

Directed energy weapons will be mounted on ships, planes, jeeps, helicopters, even individual soldiers. The directed energy weapons of concern are in the TW range, and are likely to be mounted on ships, though next-generation power plants may offer MW/g power densities, allowing the superweapons to be miniaturized. A terawatt-level electric discharge would be equivalent to hundreds of lightning strikes, though the intensity of a lightning strike is not necessary to destroy most targets.

To imagine the long-term potential of solar weapons, consider concentrating the energy of a substantial area of sunlight (100 km2) within a 0.5 km2 area, causing the intensity of sunlight to be a hundred times greater (assuming 25% efficiency) in that region. Or, if it is night, projecting energy a hundred times greater than if the sun suddenly rose. Because air is practically transparent to thermal energy, there would be nowhere to run, except underground, or underwater. People on the street would be boiled alive in the intense heat. All moisture would on the air and ground would quickly be converted to steam, some with explosive force.

Welcome to the Future! :D