Thats a very popular one It's set to do a real test in 2009, when they're actually gonna shoot down a missle , or so I've read.
A chemical laser is(i'm pretty sure) a laser that uses some kind of chemical environment as the lasing medium(like gas lasers) excited by energy(electricity, or even light from flash lamps, but not sure about that) to produce laser light.
This one is in the megawatt range(or so i've read, again) and will be capable of shooting down targets miles away.
It has 2 "low powered"(kilowatt) IR lasers just for targeting, to ready the main weapon
Nope. Instead of using electrical energy, it relies on chemical reactions between a supersonic steam of iodine and a few other chemicals to emit an extremely powerful beam. Think of it as the difference between a chemical explosion versus a nuclear explosion.