Sorry if this relates to an old thread, but I just got around to
writing up the message. This is in reference to the "starship
sensors" thread and the "thrusters are bogus (long live fusion
rockets)" thread.
First, if I were concerned about the passive sensors of potential
hostiles, I would not be cruising around at 3G on fusion rockets.
They must be very easy to detect, especially by passive IR.
Second, if I were a concerned world government, I might not allow
fusion takeoffs from or landings on the world surface. Damage to the
environment, population, etc.
So, what would be wrong with having two maneuver drive systems in your
spacecraft? One fusion rocket drive for in-system performance, and
one grav drive (not thrusters) for planetary use. OK, so this adds
some extra hardware. But the grav drive just needs to be big enough
to produce the highest G to get you off a world, no more than 2G. The
two drives could both be used in-system, with a 50% reduction in
efficiency in the grav unit beyond 10 diameters. And when you don't
want your exhaust lighting up the passive sensors for half a parsec,
cruise on the grav unit (at 50% efficiency).
Of course, if my thinking is skewed, I'm sure you will all let me know.
Chuck Hamilton [email removed]
"Two days ago I saw a vehicle that
would 'aul that tanker. You want
to get outa here..? talk t' Me."
- Mad Max
_The Road Warrior_