OK I've been kicking around an idea for a sort of stardrive. It doesn't need much new technology but it does need some. However I have one or two problems with it and wondered if any good people could help or shoot it down in flames if I've missed anything obvious. We are not talking FTL, so journeys are still going to take a long time. One of the biggest problems is how to carry enough fuel to accelerate a spaceship up to close to the speed of light and decelerate again. Let's say we want a cruising speed of .8 lightspeed which would give around 65 years to travel 50 light years. Now, one way around the fuel carrying problem would be a ram scoop style of drive (my personal favourite actually). However there is considerable doubt whether the accelerating force would actually be greater than the decelerating drag caused by the ram scoop itself. So I started thinking of alternatives... How about not carrying the fuel with you? In fact the starship itself would only carry limited manoeuvring fuel. Instead it would be accelerated up to cruising speed and decelerated at the other end by a fixed mass driver system either within the star system or just outside it. "Ok" I hear you say "sure, but those kind of accelerations would leave humans a reddish pulp spread all over the bulkheads." But, and here comes the new technology, what if all the crew are in deep freeze? In deep freeze their bodies would be solid and capable of withstanding much higher accelerations. Question; I wonder just how high an acceleration a frozen body could take (if appropriately supported) before internal bits started snapping? Maybe, before freezing, all internal cavities are filled with some substance that will freeze to great strength and be easily flushed out aftwards. Freezing also has the side benefit that the crew could remain in deep freeze throughout the flight, allowing the ship to be very small and only have to provide power to maintain the crew cryo systems. Even that shouldn't require much, with no conscious crew the ship could be allowed to drop to the ambient temperature of the space it travels through, also reducing the energy needed to maintain the cryo systems. So far so good (maybe) but now the problems begin. Let's suppose we can generate (and our ship and cryo systems can manage) an acceleration of 1000g. Thats a heck of a lot, I know, but just go with it for now! At 1000g the mass driver acceleration would have to be maintained for 6000 million km in order to reach a speed of .8 lightspeed. That's roughly the distance from the sun to Pluto! Anything less than .8 lightspeed starts making the journey simply too long. So, for example, an acceleration of 500g and a cruising speed of .6 lightspeed takes the journey time up to over 80 years and the acceleration stage would still be 4500 million km. Not much better really. So here's the real question; do you think it would be possible to construct a mass driver that is circular, round which you are accelerated until you reach your required speed before being relased off on your journey? Would the centripetal forces be too much to control magnetically? Maybe the mass driver could encircle a (small?) planet allowing the planet's gravitational field to assist in that control? Oh incidentally another mass driver would be needed to decelerate the ship, storing the energy generated by that deceleration ready for the next launch. OK the very first journey would take much longer, with maybe a light or magnetic sail for deceleration, before the destination mass driver is built. So any thoughts?