Back in grade school and high school in the late 60s/early 70s, there
was a common poster in science classrooms that gave data on various
sorts of reaction drives.
I remember the figures for a few sorts of drives (all figures to one
significant figure)
drive specific impulse
chemical 400 (shuttle main engines are about 420)
"nuclear heating" 800 (Heinlein's ships using "single H")
fusion 600,000
photon 30,000,000
Specific impulse is (roughly) defined as pounds of fuel per second per
pound of thrust. Or you could use kilos, or tons. (Yes, I know that we
are mixing mass units with force units, that's the way it's done)
When I first bought Traveller I checked, and found a comment that
stated that a ship running at 1g on maneuver drive would have about a
weeks fuel. I worked out the specfic impulse, and it came out very
close to 600,000. I guess they read the same chart. Note that a Saturn
V (6 million pounds thrust) would only need 10 lbs per second of fuel
if it used a fusion drive.
This makes calculations *very* easy. And note that for a manuever
drive, the "inefficiency" is because you *have* to throw away a lot of
the fuel as reaction mass.
Also, note that the exhaust plume is *very* hot. Probably glowing in
the ultraviolet! You'd see it as this incredible purple color. And
"tailgating" isn't advised. And landing will tend to burn holes in
*anything*.
The *basic* rocketry equations are quite simple, though you can mostly
ignore them for a fusion drive as the mass ratios become so low, that
you can ignore them for most manuevers.
Finally, a photon drive, is nothing more than one *hell* of a laser.
I
would be like. You could easily use it for carving *planets* into
chunks!
Oh yes, with the scale of fusion they have in Traveller, you don't
*need* transmutation. Just convert rock, asteroids, *garbage* into a
plasma. At a high (but not unreasonably so, compared with some of the
fusion reactions discussed here) temperature, *all* chemical bonds
fail. So you can run the plasma thru what amounts to a overgrown mass
spectrograph, and seperate out not just pure elements, but likely pure
*isotopes*. And after the capital costs, it'd be cheap to operate.
Store "junk" elements as convenient compounds (like silicon dioxide)
and use the rest. So what if gold is only a few parts per million?
Guess how much that adds up to from even a *small* asteroid.