Which of the the TL10 and TL10^ (limited superscience) reaction engines in GURPS Spaceships are cost-effective and otherwise good for ground-to-orbit/orbital-to-ground cargo and passenger shuttles? Which are cost-efficient and good for orbital operations? Which are cost-efficient and good for interplanetary operations? I can do the calculations of course, but there’s no sense in re-inventing hot water is some else has done it already.
A winged shuttles the thing? Aerobraking?
I suspect that the cost multiple on ram-rockets is way too high at five times the cost of a rocket fed its reaction mass from tanks. For Flat Black I’m thinking of ruling that a ram-rocket has the cost of a reaction engine plus half that of a jet engine of the same size. Any thoughts?
I think the price for antimatter used in GURPS Spaceships is taken from Robert L. Forward’s Indistinguishable from Magic, and that was an estimate of the cost of making it using current (c. AD2000) methods in a purpose-built facility. Anyway, it is wince-inducingly expensive because the process is profligately wasteful. That technology is literally to make all possible particles at random and keep the ones that happen to be positrons. I’d like to assume that a limited-superscience method will be invented in the future that is at least one order of magnitude cheaper, and that (like all historical energy technologies) it becomes another order of magnitude cheaper as it develops to maturity, so that Tau Ceti is manufacturing antimatter in tiny quantities for G$100 billion (₢25 billion) per tonne. Antimatter-boosted propellant would then be available for $G120,000 per tonne.