Quote:
Originally Posted by TomW
I've read the first four books and I agree they are mostly logical - with the exception that they apparently are capable of generating a localized gravity field at 90 degrees to the ships thrust vector. Also, they generate a constant acceleration with a mass ejection propulsion plant (basically, a rocket) which apparently needs no mass to eject.
TomW.
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The speed of a ship that uses an kind of rocket-like drive depends on two factors: the ejected mass, and the speed of the ejected mass. (momentum = mass*velocity). Chemical rockets have exhaust velocities that are around thousands of meters per second. that's fairly low; exhaust velocities in ion drives are in the hundreds of thousands, and C is 300,000,000 meters per second, so you can posit a ten-thousandfold increase in exhaust velocity (and thereby specific impulse) and still be within the realm of physical possibility. Then your fuel tank can have the size of an SUV's gas tank and still take you all across the solar system. Also, your drive becomes a literal death ray, but that's beside the point.