Re: World building: implications of counter gravity

If you have a strong light rigid material that can contain a vacuum you
could get to the edge of space by buoyancy.

The material might also be useful for solar sails.   Add some ion drives
(solar powered) and regular rockets for final orbital insertion and you
may have a cheaper system.

Andy.

________________________________
From: Gzg <gzg-bounces@firedrake.org> on behalf of Tony Wilkinson
<twilko@ozemail.com.au>
Sent: Wednesday, November 8, 2017 4:40 AM
To: gzg@firedrake.org
Subject: Re: World building: implications of counter gravity

Years ago a mate and I did some thinking about various space drives for
an RPG setting we were dreaming up. We didn't think of counter gravity
but we did think of a magnetic drive using superconductors that could
push against the magnetic field of a planet to get lift and motion. So
in Earth's gravity you could lift off and achieve orbit relatively
efficently but it dropped off rapidly as you moved away. Wouldn't work
for most bodies as there is no significant magnetic field to push
against but bodies like Jupiter it would work a charm. This would also
stop people throwing asteroids about as there is no magnetic field for
the asteroid to push against except that of the Sun which would be
pretty weak that far out. Also it would require a reasonable amount of
power run so that might be another reason to limit asteroid bombs.
Just a thought or two.

Tony.

On 8/11/2017 8:02 PM, Richard Kirke wrote:

I think you'd end up using gravity wells to "sail" with. This would be
an adaptation of the current slingshot navigation used by spacecraft in
the solar system except once you have built up as much forward momentum
as the gravity well provides (I have no idea what the proper term is)
the pilot switches on his counter-gravity generator to get a further
boost.

My guess, and orbital mechanics are well out of my field (which is
soda), would be that this would result in a limited number of optimum
space-lanes (which would shift due to the way all the planets move in
relation to each other) but that exta-system travel would be barely more
efficient than before.

I think popping a counter-gravity engine on an asteroid would probably
prevent any Armageddon scenarios quite readily though...

Just some thoughts as my brain warms up this morning so the above may in
fact be nonsense...

Richard

________________________________
From: Gzg <gzg-bounces@firedrake.org><mailto:gzg-bounces@firedrake.org>
on behalf of Hugh Fisher
<laranzu@ozemail.com.au><mailto:laranzu@ozemail.com.au>
Sent: 08 November 2017 08:54
To: gzg@firedrake.org<mailto:gzg@firedrake.org>
Subject: World building: implications of counter gravity

I am doing some world building for a space game setting, and want to run
an idea past people.

My setting is not too distant future. I want easy surface to orbit
launch
to explain why people are in space, which means using up a lot of energy
on each launch.

BUT once in space I want engines to be rather limited, so it isn't easy
to, say, divert asteroids into planets.

My idea is counter gravity, an updated version of HG Wells Cavorite, or
the liftwood in Space 1889. Not artificial gravity, but some kind of
field
that INSERT HANDWAVING HERE creates an equal and opposite thrust
reaction.
So within the gravity of a planet you get lots of thrust, near an
asteroid
very little, and from a spaceship hull something only measurable in
nanometres per hour.

What am I missing? Would this make space travel economical? What else
would it be good for?

--
	 cheers,
	 Hugh Fisher