mrspeedybob said:
This video is from 2007 but it stated the goal at that time was a 64 mega-joule weapon? I understand the advantages of extended range but it seems like a huge, awkward, and expensive weapon to deliver a relatively small amount of energy. 64 mega-joules is the equivalent of only 14 kg of TNT. Aren't there already much more efficient ways of delivering that amount of destructive energy to a target?
It is the speed, not the explosive power. A rocket with the same explosive power would be moving much more slowly than a projectile launched by a rail gun.
The 64 MJ is carried by the kinetic energy of the projectile, not the chemical energy of the projectile. If a light projectile were carrying 63 MJ of potential energy and 1 MJ of kinetic energy could be traveling very slowly. However, a light projectile launched by a rail gun could have 64 MJ of kinetic energy and 64 MJ of explosive power. The light projectile would be moving much faster.
A rail gun is one example of a kinetic weapon. A kinetic weapon is one where most of the explosive energy is "stored" as kinetic energy.
Kinetic weapons would be the weapons of choice in outer space where there is no atmosphere. An rocket in the atmosphere has to store chemical energy both for explosive power and to counter air resistance. Relatively little chemical energy would be left for explosive power.
There is a historical cycle going way back. Kinetic energy weapons used to be popular in cannon. Cannon balls were kinetic projectiles. Most eighteenth century cannon balls did not carry explosives. They were launched by explosives but their damage was induced by their kinetic energy. This was great for short distances, where air resistance is negligible. Then, the use of explosives in projectiles became more popular as the range of cannon increased. Then, kinetic weapons came back as humans started to go into outer space. Those supersonic uranium projectiles that you heard about in the news is a kinetic weapon.
The distances in outer space cause large delay times in projectiles. The target could see the projectile coming from a large distance using light or radar and move out of the way. Nothing goes faster than light or radar. There will also be a delay for the projectile seeing the target move out of the way. Therefore, the most effective projectile will be the fastest projectile in outer space.
Speed would become far more important than efficiency in outer space. If battles were to occur entirely in outer space, rail guns and lasers would be the weapons of choice. Both are kinetic weapons in the sense that the energy that does the damage is stored entirely as kinetic energy.
These weapons would be much faster than rockets. Lasers would be faster than anything. However, lasers could be countered by reflective surfaces. So that would leave rail guns.