Re: Real Space Combat Help:

Samuel Penn wrote:
> Sounds good, but I don't like Renegade Legion itself too much,
> and getting hold of it is a real pig anyway.

Not like RenLeg?  Heretic!  He must be burned!	The Terran Overlord
Government will see you crucified, Commonwealth scum.  ;)

> There's also drive systems to take into account - ask any Kzin :)
> (a reaction drive puts out lots of energy, over a reasonable
> range, so even an 'unarmed' freighter has at least one weapon).

Depends on what you consider reasonable range.	If you're using ionized
Hydrogen or Helium for acceleration mass, you're probably not going to
be throwing enough out to provide a decent impediment to someone not
/incredibly/ stupid, flying up your tailpipe, as it were.  Dispersion'll
take it to less than the density of a nebular area darn quick.

> Another type of missile is a nuke which is used to power a (one shot)
> gamma ray (or other high frequency) laser. A good example of this
> sort of combat is at the end of Footfall, by Niven and Pournelle.
> Lots of use of burst lasers.

I'm not altogether sure I buy the science behind `porcupine
Gamma-blasts,' as it were.  You have to have a damn quick means of
focusing the energy before the focussing equipment itself gets blasted.

> The big problem in space is delta-vee - or rather the lack of it.
> This is a measure of how much velocity change a vehicle can perform
> before running out of propellant. For missiles, you generally want
> to close with the target as quickly as possible - which means
> burning lots of thrust early on. Which leaves almost nothing for
> the close-in manouevering needed at the end of the flight to get
> a direct hit.

Two-stage, definitely, with a seeker period before final terminal
impact.  Good way to sow a quickie minefield, to shake pursuers, for
instance.  Fire missiles, then have the seeker wait for some time before
going terminal.

> For kinetic kill, you probably want railguns rather than missiles,
> they're a *lot* cheaper giving that success ratio is going to be
> extremely low in either case. If you've got a guided missile,
> it's probably best putting a nuke on it.

For the mass invested, a smart missile is going to be a /lot/ more fuel
efficent for /you/ to carry around.  Successful hits will be much more
oft seen because the seeker will take the missile in as close as
possible before turning loose the submunitions.  Gauss cannons have to
compute based on the information /you/ can see, not from far closer to
the target.

> I have my doubts about the use of fighters in realistic space
> combat, but then I'm part of the 'big ships are better' crowed,
> and fighters are just a very small ship.
> 
> What may be useful are drones - unmanned fighters carrying limited
> duration weapons (a few missiles, or limited power for direct
> energy weapons). For a small fighter, too much of ship mass is
> wasted on life support for the pilot. At close range, they're
> fragile enough that survivability probably won't be acceptable
> for a manned weapon system.

Think of fighters as drones with organically produced seeker modules
with recoverability.  All a missile really /is/, at core, is a drone
aircraft/spacecraft that carries some means of dealing death to the
target.

If its difficult (for whatever reasons) to build sufficently smart
seekers, pilots will be the guidance system to take death from the cap
ship to near the enemy, within the maneuver sphere to where the AI
seekers are good enough to impact.  If AI's are sufficently intelligent
to take the death there themselves, there won't be much need or use for
fighters.  Its a function of sensor and intelligence technologies.

> Very true, but lasers make for good point defence against missiles.

Both missiles and Casters (gauss cannon, sandcasters, anything that
throws out mass in the way) will be good against missiles on the close. 
Lasers have the advantage of not leaving a huge mass floating near your
ship to provide a hazard to /other/ ships.

> Something else that should be said, is that any ship with a
> limited delta-vee can't keep on dodging for ever. It's often
> claimed fact is that you can't hit a target at light-second
> distances, because it can dodge in time. But since the ship
> doesn't know 'when' it's going to be fired at, it has to dodge
> all the time, which is going to burn propellant way too quickly.

Of course.

> I tend to see ships as going for heavy armour rather than
> manoevrability, with lots of direct energy weapons. At any
> decent range the lasers won't do much damage (laser intensity
> falls off with the square of the distance), but it persuades
> the enemy to keep away from you enough so that they can't
> use their direct energy weapons. Greater range also means
> longer flight time for missiles, giving you a better chance
> of detecting, tracking and destroying them before they get
> you. Regardless of armour, a single nuke can really ruin your
> day.

If you go for heavy armour and plodding maneuvers with laser weaponry,
my fleet that's built on fast maneuvering and projectile weaps will
/always/ be able to get around your maneuver sphere, stay out of your
effective range and throw things into your maneuver sphere that you
won't be able to dodge.  Of course, I'll have limited endurance before
I'm out of mass to hurl and if I /am/ hit, I'll be reeling.  Both
strategies have their uses, which is why a balanced interstellar fleet
should make use of /both/.  A fast picket line and escort groups
supporting a solid line of cap ships with much /larger/ projectile
throwers and the energy output to support a bristling array of
short-range beam weaponry.  The smaller ships really are better off with
projectile weaps because their effective range is so much larger at
incident velocities.

> If the enemy controls orbit, then don't *ever* fight an open ground
> battle, unless you're absolutely positive all enemy weapon platforms
> will be over the horizon.

If the enemy controls orbit, you're done for /anyway/.	Your surveilance
sats will be very short lived, you're going to be washing in a rain of
THOR and arty missiles and anytime you stick a nose out of cover, you're
going to be seen if not bitten.  Once orbit is taken, unless the
attacker is understrength, you might as well give in.  If the enemy /is/
understrength, their best tactic is to take and hold local orbital power
and consolidate through ground forces.

(Prefect models this /very/ well.  You can take any strategy you like,
but unless you have at least temporary orbital local control, you're
about to get pasted.)

> A ship with a human crew will have at least part of the ship at
> around 300K, against a background of about 4K. That's ignoring
> heat from reactors, drives (they don't cool to background temperature
> as soon as they're switched off) etc.

IR /is/ radiation, you know.  :)

> The problem with this is, either you're willing to wait months or
> years to get to the target, or you have to start your 'fall' at
> extremely high velocity - which means flashing past the target
> at several thousand kps.

Flashing past may be perfectly fine on a recon pass.  Especially for the
carrier, which will be out of the ecliptic, anyway.

> This isn't as bad as it seems though, because you just launch a
> big volley of missiles before you close, which will hopefully
> close to within killing range of the enemy before they can react
> (or even detect them). In a matter of seconds, you could destroy
> the enemy fleet.

High-speed attack passes can be /loads/ of fun.

> You then spend the next six months decelerating, and coming back
> to the target world to actually capture it :)

Hopefully, you're smart enough to have a second wave invasion fleet.  :)

> If attack a world, this is of course what you'd use. A world can't
> dodge, and follows a totaly predictable orbit. Launching the rock
> two years ago isn't implausible.

Of course, you may want to /inhabit/ the world after, but for relatively
genocidal bombardment, big rocks down the well are perfect.

> As soon as they make a burn though, you know where they are, and
> where they're going. Even if they go dark, and are undetectable,
> you still have a very good idea where they are over the next few
> seconds, minutes, hours or even days or weeks (depending on how
> good your computers are).

All you know is where they are /right that minute of the burn/. 
Directional information is something you /don't/ have.	That's why you
know the maneuver sphere, not cone.  I /might/ be decelerating to a
stop, or accelerating to twice my original velocity, you have no way of
knowing.  Further, if you guess wrong and look in the wrong direction
for my next burn, you may miss it, and even if acquired later, have no
real idea of my true velocity and momentum.

> On top of that, they *will* be detectable. If you know where to
> look, it is very easy to detect something in space. If the enemy
> isn't expecting you, creeping up on them undetected may well be
> an option.

Space is a big place.  Looking is hard.

> Good. The enemy wants you to do this, because you've just told him
> where the carrier is. One dead carrier. Want you want to use are
> disposable weapon drones which you leave to die. The carrier only
> reveals itself if the battle is won. If not, it follows its
> trajectory out away into space.

You can't track predictibly if all you know is that a burn took /place/.
And that's all you can really tell at the ranges and velocities we're
talking here.  You just did your final burn to bring you into contact
with your carrier.  The observer has /no/ idea whether you've just
burned toward out-system (to rendezvous) or are doing a six-point turn
to high-speed attack his outer rim outpost.  If its in your near-term
maneuver sphere, it /could/ be either.

> any of the films...). It brings up the good point that battles
> will generally be fought around planets. There's no point
> defending empty space, since it's not useful, so it makes more
> sense to concentrate your forces at some strategic points.

THIS is absolutely true, and something you learn very quickly playing
Prefect.  On the other hand, as attacker, its oft very useful to bring a
group of ships into inner-system space at some outre' location and set
up a transient resupply base out of a bunch of tenders lashed together. 
Its unlikely you'll be spotted if you're careful, and then you can burn
almost anywhere in-system and they'll be confused as to your real
destination if your maneuver sphere also intersects a few target
localles of theirs.

-- 
[  Alexander Williams {thantos@alf.dec.com/zander@photobooks.com}  ]
[ Alexandrvs Vrai,  Prefect 8,000,000th Experimental Strike Legion ]
[	      BELLATORES INQVITI --- Restless Warriors		   ]
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