On Tue, Aug 15, 2017 at 3:35 AM, Tim <xxxxxx@little-possums.net> wrote:

 > I'm certain that a ship could hover instead of setting down, in a way
 > that addresses all the safety concerns in this thread and so on.  I
 > just don't see yet what advantages that would offer.

You wouldn't need to put landing feet into your spaceship, along with all the bracing
structures (and associated extra mass and volume) that these would need. And you
don't need to rebuild your landing field after every ship lands and leaves some
huge dents in the ground / cracks in the concrete.

I've always hand-waved that CG works both ways. So a ship hovering can easily set up
a net pull "down" to anchor it in place against winds etc. If you set up a 2G pull
"down" and the same force "up", then the ship hovers, but winds have to overcome both
the mass of the ship and the two opposing drives, which makes it a lot more stable.
Imagine a ball hanging from a piece of stiff rope, rather than from a thread.
Blow on the ball and the piece of rope is going to soak up a lot more of that wind
energy than the rubber band. (I.E the system is now acting as a heavily damped pendulum.)

Or you might think of the grav drive embedding itself in, and so operating against the
local gravitational gradient (the famous depression in the rubber sheet picture), rather
that being a point-to-point interaction between the drive and the local centre of mass
(e.g. the planet). The effect is that a hovering ship effectively has multiple points
of support.

IM(HV)TU big ships stay in orbit (usually...) and use shuttles to get "stuff" to/from the
surface of a planet. Beanstalks exist and are rare and restricted to highly developed planets.

Side thought: If you *do* land on a planet, presumably you want to maintain your internal
ship gravity. If you happen to run your ship's gravity at 0.5G, and you land on a 2G planet,
then you are, I think, unlikely to want to subject everyone to the native 2G, just so you
can save some fuel by not operating the internal CG. Usually :-) (just throwing in a plot
hook there).

Standard disclaimer: I have no idea whether any of this is canon or not. It may not even
obey the laws of physics-as-we-currently-know-them. I like a Universe which is more-or-less
self-consistent, but I don't care much about how it gets that way. It must also allow my
players to Get Stuff Done. They get really peevish when Reality gets in the way.

Hey, is it time for another 'Stupidest Things your Players have Tried To Do' thread?

Jonathan