Re: Orbits Defined

On 25 Jun 98, at 9:58, Yum Yum Yab Yum wrote:

> >Ermm.. the way you explain that makes it sound like geostationary
orbit
> >requires you to be at a particular distance. In an /unpowered/
spacecraft
> >that's true - centri(petal?) forces are strictly defined. 
> Geostationary orbits do require a particular distance. At least a
minimum
> distance. For Earth this minimum distance is 35,000 km.
Grin. I know. It's a classic undergraduate physics problem to get the
students to work out 
exactly what distance a geostationary satellite would have to orbit at.

> >A spacecraft capable of moving under it's own power can 
> >actually maintain geosynchronous orbit at any altitude, simply by
using
> >it's drive system to maintain the correct velocity.
> If you are using your drive system to maintain position, you are not
'in
> orbit'. By definition to be in orbit you aren't using your drive
systems,
By what definition? By the definition I know, if you are in a 'flight
path' which circles a 
planet you are in orbit. Whether you are powered or not is irrelevant.
Does this mean a 
space shuttle isn't 'in orbit' while it's firing it's manoeuvring
thrusters? Or the satellite 
launching from it's bay isn't 'in orbit' until it's rocket stops firing?

> but using the gravity well of the object to dictate your velocity. If
you
> want to maintain a stationary position above a certain point over a
planet
> and be significantly less than that planet's geostationary limit, you
need
> to apply drive power to prevent you from falling down the gravity
well,
> and you are not 'in orbit'. Everything else in orbit will be whipping
by
> you quite fast.
Um, no. A ship capable of variable drive can maintain any distance and
'orbital speed' it 
wishes, providing it's navigation and control systems are up to it.

> >Seeing as how FT is a space combat game, wouldn't a better definition
be
> >that
> > low orbit 
> >is at a range suficiently small to engage ground targets (and be
engaged
> >by them) and high orbit is out of range? Presuming a planet could
have
> >enhanced range SLM's that means (what?) 48MU is low orbit. 
> Depends on the scale of your planet.	;-)
That defines the exact area I agree - a one side of the table = planet
game it becomes a 
'bar' across the table, whereas actual circular planets scribe a bigger
circle. The thing to 
look at may be that there's no point arguing about what is 'high' or
'low' orbit (or indeed 
orbit at all) unless it has some functional meaning in a game of FT,
interesting as it might 
be to discuss the physics of it.

			TTFN
				Jon
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