Satellite-Mounted Space to Surface weapon

[Canmoore]

Now, I know that conventional weapons cannot operate in zero-gravity. However, we do know that Lasers do. I am taking this idea from the Classic strategy game Command and Conquer.

A super-weapon satalite system called the "Ion Cannon", is able to emit a huge charged laser type beam of energy onto a fixed location. Releasing a devasting amount of energy dystroying the target and anything nearby.

Now my question is, Do scientists know if it is possible to focus a large beam of energy from a Satalite mounted weapon, and use that energy to destroy a target on the earths surface? The Star Wars anti nuke system comes to mind, however that was only going to dystroy ICBM's.

[wkllaw]

If they do know how to do that then it must do a lot of damage before they decide to because if they arm satellites then they could still do alot of damage by arming them with other things and that way may seem cheaper as well as more destructive.

[FOG3]

...

Problem 1: Power.
Just where are you getting the power for your high energy beam? The max energy from solar at this distance from the sun is only about a kilowatt per square meter, and unless you're going to spend inordinate amounts on the panels you're only getting around 10% efficiency. So either you have a gigantic array or you're going to have a long time between firing.

Problem 2: The atmosphere and everything else in between.
There's a very good reason we have had issues with making combat worthy lasers, the beam is degraded a lot by the air.

Problem 3: Weight
The existing SDI equipment was meant to fry targetting circuitry and was serious tonnage for the particle beam cannons. To actually get it up to fry the building/city level would mean we're talking something very, very big and heavy.

Problem 4: Vulnerability
All some smart aleck has to do is send up some junk into the appropriate orbit to work as micrometeorites and seriously damage this massive piece of equipment.

The whole beam satellite for ground attack concept is like bipedal mecha, more $$$ for less bang to the point of absurdity. Rods from God does that same job much better/easier/cheaper.