RE: [DSII] When gravity fails

From: ~ On Behalf Of Christopher Downes-Ward
Sent: 01 May 2002 11:54
Subject: [DSII]When gravity fails

> Thinking specifically about movement of wheeled vehicles
> and infantry, how does lower gravity affect movement. 

The very low-G / zero-atmosphere has been covered by
earlier posters and also in past threads. I'd like to
bring in near-G / thin atmosphere environments.

First of all, is it right to associate thin atmospheres
with low surface gravity? As a simple rule of thumb it
will do, but at some point the average density of the
planet will become a factor. The problem is, I don't
know how "trivial" a change in, for example, the Earth's
density would be needed to give us a radically thicker
or thinner atmosphere.

There is also the possibility that your planet has not
been formed with the same cocktail of gasses as as the
Earth. Combine this with the density and you may have
an atmospheric pressure that falls off much more quickly
or slowly than we are accustomed to.

I know there are r.a.sf.s lurkers on this list. (Too
many threads have been too similar for them all to be
coincidences.) You are hereby invited to prove your
scientific prowess, or at least recommend a decent
book on planetbuilding that is still in print.

If your vehicle engines require oxygen then the
proportion of O2 to other gasses in the atmosphere 
will affect CFEs. Do MHTs require external oxygen?
The FGPs will of course be unaffected, although "air"
density will have a big impact on GEVs and aircraft.

If the atmosphere is thin but the ratio of oxygen to
other gasses is normal then the classic supercharger
will help. If oxygen is simply scarce, troops will need
bottled oxygen and vehicles will be battery-powered if
no better powerplant is available.

> How does lower gravity affect wheeled vehicles?
> Lower gravity means lower traction, so do they
> actually get slower?

If engine power is maintained, you also have a higher
power/weight ratio. However, I would think that it's
still mass that counts, not weight, so a vehicle will
be no faster. Is weight or mass the main limiting
factor on the durability of suspensions?*

Yes, traction will be lower, but is wheelspin really
a problem for many AFVs? Ground pressure will be
lower, so there should be less chance of becoming 
bogged down.

All real-world information on the care & feeding of
AFVs welcome here.

* painting here with a very broad brush to include
  everything from transmission through to the actual
  wheels / tracks / gubbins...

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