Re: Sensor Range Question [Evasion]

On Wed, 28 Apr 1999, Nyrath the nearly wise wrote:

>	The reason most jump drives in SF use fixed jump points
>	is the reason given in Pournelle's "The making of the
>	Mote in God's Eye".

i really must read that ...

>	Without the choke points mandated by
>	fixed jump points there would be few, if any, space battles.
>	Space is so freaking huge that battles can only happen
>	by mutual consent, lacking such choke points.

a common theory. i'm not entirely sure i believe it (who woulda thunk
it,
eh?). basically, the theory is that without special points in space,
there
can be no battles, as battles have to take point at a certain point
(well,
within a certain relatively small volume). i have two objections.

firstly, there are plenty of special points other than jump points:
planets, for instance, and artificial orbiting bodies such as space
stations. if i have a planet in a system, and an enemy invasion fleet
jumps in, i think i have a pretty good idea where he's heading, and that
there will be a battle there.

secondly, i don't think battles do need special points. the same theory,
applied to modern naval or aerial warfare, would predict a lack of
battles, when in reality there is certainly no shortage. in these cases,
the sites of battles are decided by interception: one side will chase
the
other until they meet, and then they will fight. this, in turn, depends
on
the relative speed and points of origin of the forces.

consider how few major naval or aerial engagements have been fought at
targets: the battle of Jutland was at Jutland because that's where the
fleets were when they met, not because someone was going to Jutland. the
battle of Britain was fought over a gigantic patch of sky, not around
the
targets the germans were attacking.

example: if i have a fleet at anchor in orbit around Gamma Hydri Prime,
and my enemy jumps in to the system at local coordinates 3728 mark 489
stroke 90 dash ZZ9 plural Z alpha, then i have two defined points; it is
then just a matter of maneuver until we meet. or, i could hang around
and
we could fight at the planet.

the main objection to this objection centres on distance; my
interception
objection only holds water if a fleet can detect another fleet in the
system at multiple AU range. the FT background suggests it can, and i
think it's legitimate within a space opera context.

i'm not so sure about the hard-sf edge: it all depends on how bright
your
drives are, i suppose.	i reckon with a 3m telescope mounted in each
FireCon centre in the fleet (in a typical fleet, maybe 20 telescopes?),
ganged up as an interferometer (possibly by aperture synthesis, or am i
barking up the wrong tree here?), and spread out over a sphere with a
radius on the order of a quarter of an AU (purely arbitrary) you'd have
a
decent chance of being able to track an enemy fleet.

you would have to initially acquire them by their jump signature (think
gravity waves, tachyons and magnetic fields, etc). the attacking fleet
would probably be able to figure out where the defending fleet was from
the positions of planets.

Tom