On Sat, 29 Aug 2009 15:17:58 +0100, Cherry Chapstick
wrote:

Spacecraft are potentially the most fuel-efficient mode of transport
in terms of passenger-miles per gallon of fuel.

I don't see any numbers there relating to spacecraft and pm per
gallon. I don't see any information there, either, that can convert
the solid rocket fuel into a 'gallon of fuel' equivalent. Perhaps I
am being short sighted.

You are. A spacecraft can travel forever at millions of miles per
hour on no fuel whatsoever. Therefore it must be *potentially* the
most fuel efficient method of transport. I chucked it in my post as a
semi-humerous observation, but with the serious point that such
comparisons are not always a valid way of looking at things.

--
Cynic