RE: [FT] Vacuum-Head Help Required!

> -----Original Message-----
> From: Barclay, Tom [SMTP:tomb@bitheads.com]
> Sent: Thursday, November 30, 2000 1:39 PM
> To:	Gzg Digest (E-mail)
> Subject:	[FT] Vacuum-Head Help Required! 
> 
> Okay, Breathers of The Cosmic Emptiness, please share with me your
wisdom
> in
> its ample supply! 
> 
> Orbits - I have a bunch of defsats/stations. I want them to orbit a
> planet.
> Assume the following details in answering the questions:
> 
> Planet diameter Dp = 6-8" (6000-8000 km);
> Game scale = 1000 km/inch;
> Turn length = 15-20 minutes;
> Satellites are defense platforms to protect the planet from invasion
or
> orbital attack.
> 
> Q1: Do I want such objects in geosynch or non-geosynch orbit? Why? Why
> not?
> 
[Bri] Non-geosynch orbit. Geosynch orbit is useful if you need to 
view the same portion of the planet for long periods of time. Or to
simplify finding the satellite from the planet (communications
satellites). 

> Q2: In whichever case you suggest is appropriate (geosynch,
non-geosynch),
> what is an appropriate distance from the centre of the world to locate
> these
> satellites for a standard non-decaying orbit?
> 
[Bri] It depends if you want accuracy or playability. If you want play
ability, you could use the orbits in MT p.13: Orbit is at a distance
from the center of the planet equal to the diameter of the planet
(or distance above surface equal to the radius of the planet).

> Q3: How fast should these move in one of these 15-20 minute turns?
Would
> your answer be measured in angular degrees per turn or in inches along
the
> orbital path? 
> 
[Bri] If using the MT method, velocity should equal the radius of the
planet orbited.

> Q4: Would your answers to the above questions change, and how, if
these
> platforms purpose was to act as ortillery platforms and as
surveillance
> platforms for the planet rather than defense sats? And would it be
> possible
> to have one satellite constellation provide both roles? If so, what
> orbital
> parameters would such a system require?
> 
[Bri] If you need to have an area observed constantly, you either need
multiple satellites where one will be covering the area as one goes out
of range or geosynch satellites. For geosynch, divide the rotation of
the 
planet into 15 minute sections. Then divide the planetary disk into a
number of sections equal to the number of 15 minute periods. The 
geosynch satellite would move from one section to the next each turn.
So, if over Earth, you would divide the orbit into 360 sections and 
move it one section per turn. In the case of Earth this is easy. just
lay a protractor over/under the planet and move the satellite 1 degree
each turn. (Gee, those Babylonians were smart).

> Q5: Is there any modification to weapon attacks against these
platforms
> that
> is appropriate given they occupy a fairly set movement pattern and are
> therefore inherently predicatble? Treat effective range as 75% of
actual
> range or some such thing? 
> 
[Bri] See below.

> Q6: Should these be constructed as ships without drives or FTL but
> otherwise
> as a vessel? 
> 
It depends on how large they are and what their range will be [See 
Below]. If they are large (over mass 2) platforms with major weapons,
that are incapable of movement, then cost them as non-FTL, 
non-MD ships. Otherwise, see below.

> My thanks (in advance) for the replies from the many learned members
of
> the
> list. 
> ------------------------------------------
> Thomas R. S. Barclay
[snip]
> ------End Original Message-----
> 
> 
My comments above are marked by [Bri]

If I were to choose an orbital defense system, I would make them much
more like dormant fighters. Small, but efficient.

Starfire Defense Satellite:
Cost: Same as fighter +2 
Mass: Same as std. fighter
The Starfire is in actuality an AI controlled fighter. It is placed in
orbit
around a planet and augmented with solar collectors to maintain 
power when not activated. Once activated, it performs as a standard
fighter. As with a fighter, it may not be targeted by non-PDS weapons.
Once activated, it has an endurance of 1.5 hours of active engagement.

Treat it as a 1 fighter fighter group that does not make morale checks
and may not be refueled. It must, however stay within 72mu of the 
planet it protects. It has an endurance of 6, and may use secondary
movement (although this cuts it endurance). Usually these are 
purchased in bulk in hopes of overwhelming an opponent's PDS/ADFC
net.

Specialized versions exist:
 - Interceptor
 - Attack
 - Long Range  
 - Fast
 - Torpedo
 - Heavy

A planet could purchase quite a few of these cheaply.

if a major world, I would suggest that a planet have a good number of
real fighter groups, a number of missile launchers (MT and Salvo),
and Heavy Weapons (Beams, P-Torps, etc.), and MANY PDS
sites in addition to a home defense fleet.

If it is a small world, it may only have a defense grid.

If a very small colony (Hadley's Hope), it may have no defense at
all.

---
Brian Bell
bkb@beol.net
http://www.ftsr.org
---