The total mass you need to zap is about 150 kg, requiring up to 8 gigajoules to fully vaporize - thus average beam power of 80 MW. Now, just how big is your laser battlestar? If it is 20 meters in diameter across the aspect facing the attack, it is in line for about 15 whacks, giving you 6 or 7 seconds of zapping time per frag on collision course. When the fragment cloud passes the target it will be 5 km across, with a cross section of about 20 million square meters - meaning a chunk of nasty for every 20 square meters of target cross section. Let the wreckage fly apart at up to 25 meters per second. Big ones and little ones, but say they average 10 kg - a million of them, delivering an average punch equal to rather more than a ton of TNT. At that point the bursting charges go off and break up the bus into a cloud of fragments. Suppose a closing rate of 30 km/s, and assume that defensive laser fire will burn through the armor and wreck the bus at 3000 km = 100 seconds from the target. A few thousand tons of that mass can go into an armor faceplate, making it harder to zap. It won't be cheap, but it will be a great deal cheaper than a reusable warcraft, and it allows you to use its full delta v to build up impact speed, and its entire mass (less expended fuel) as punch. Build a 10,000 ton killer bus - or buy an obsolescent cargo hauler at scrap price. So, why build a costly 10,000 ton space battlecruiser just to deliver a few dozen kinetic missiles of a few tons each? Cut out the middleman. Which makes kinetics, unlike lasers or other weapons, a 'natural' outgrowth of civil space travel. The whole interplanetary economy is based on their ability to do so, and do it (relatively) cheaply. These people throw a lot of luggage around, and they throw it fast. If we are dealing with deep space warfare, interplanetary or interstellar, we are probably in a setting with regular, extensive space travel, passengers and freight.
0 Comments
Leave a Reply. |