Re: World building: implications of counter gravity

On Wednesday, 8 November 2017 19:54:48 GMT Hugh Fisher wrote:
> 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.

What I use in my own setting are repulsor fields (terminology taken from
Star 
Wars), which are a sort of reverse tractor beam. This is what is used by
flying 
cars, 'grav tanks' and the like, and is also used by space craft for
take off 
and landing.

It works by pushing against another mass (just like an SF tractor beam
pulls 
against a mass). Vehicles can use it to push against a planet. They can
also 
use them to push against incoming missiles in a defensive fashion. They
can't 
use them once they're actually in empty space, but could use it against
an 
asteroid.

They are relatively short range (especially at low tech levels, where
they are 
limited to a few tens of metres), so many space craft only use them for
final 
approach so they have better fine grained control on landing/take off
without 
burning the landing zone. They tend to have problems on bridges as well
(which 
don't have sufficient mass to 'push' against - the push is against
actual 
matter, not against the gravitational field).

Even high tech craft tend to be limited to a few kilometres altitude
with this 
technology, so then switch to main drives to get up to orbital velocity.
A few 
specialist craft can reach tens of kilometres.

You could use something similar, maybe increasing the range, but even
being 
able to 'hover' above the thickest part of the atmosphere would be
enough to 
make it a lot easier for a primary drive to get a ship into orbit.

-- 
Be seeing you,
Sam.
https://www.glendale.org.uk/ 
https://www.google.com/+SamuelPenn