Zor wrote:
Also, warships and colony ships are two very diferent type of spacecraft. One is loaded down with advanced manuvering thrusters and sensor systems, as well as weapons and point defense systems. Colony ships, on the other hand, are basically one shot rockets designed to accelerate to a decent fraction of lightspeed, coast for a few centuries and decelerate in a manner to get into a stable orbit of a certain star. And by the 6th century, Sol was not the only system shooting off colony ships.
Right, I should have responded to this months ago, but better late than never;
Colony ships, as you describe them, have to do the following things:
A) Carry thousands of colonists, plus the cryogenic equipment to keep them frozen and alive.
B) Carry the medical, industrial, agricultural, scientific and possibly military equipment to keep the colony going while it's getting started.
C) Carry a range of shuttles to move the above things down to its destination, and presumably a few interplanetary probes wouldn't hurt either.
D) Accelerate all of this to a decent fraction of the speed of light, which takes an ungodly amount of energy.
E)Decelerate back down to a reasonable speed once it gets to the target, taking a more godly but still large amount of energy.
F) Pilot itself though interstellar space between points D and E, for hundreds of years, with noone to assist it if it is damaged or suffers a malfunction, moreover since the entire crew is in stasis, this will all have to be done by a computer. All I'm saying is that sounds like it needs some good bloody redundancies.
Now keep in mind I'm not sure if there's a more appropriate way to work out the energy cost for accelerating a ship, and I suck at maths, but using the common garden velocity equation (1/2m(kg)*V(m/s)^2) accelerating a 1,000,000 ton ship (not unreasonable with everything it's got to carry, I think) to 1/4 the speed of light (about what most of your colony ships manage) would take around 2.8*10^24 joules. And using E=M(kg)C(m/s)^2 that means you'd need something along the lines of
7,5000 tons of antimatter reacting with 7,5000 tons of matter to get one of these monsters up to cruising speed. Then that much again to slow it down.
My initial reaction would be that that sounds like a lot, but maybe your guys have got Mercury turned into one giant antimatter factory and they can tile their roofs with the stuff.
My apologies if I've got the maths wrong or oversimplified. Though my understanding is that the figure for the amount of antimatter is actually impossibly small, since it implies 100% conversion to EM energy rather than neutrinos and weird stuff.