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> on behalf of Hugh Fisher 
> <laranzu@ozemail.com.au>
> *Sent:* 08 November 2017 08:54
> *To:* 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
>