Shields In Traveller

[Solomani666]

Plantier Shields - An Alternative to Black Globes
by Ken Pick
Do you remember when CT
Was only Books 1, 2, and 3
And a homespun setting that you wrote?
-- Doug & Kirsten Berry, "The Traveller Saga" (filksong)
In the early (pre-High Guard) days of Traveller ship design, the two widespread universe paradigms were Star Trek & Star Wars - both of which included forcefield "shields" as the basic defense in ship-to-ship combat. Since hull armor rules and Black Globe artifact forcefields were not introduced until High Guard, a lot of GMs tried to homebrew shields as part of their house rules.
This is a composite of those homespun forcefield/shield rules, called the "Plantier Shield" after the "Plantier Theory" of French UFO lore . For basic CT, it provides a basic defensive system for ships; for post-High Guard Traveller, it provides an alternative to the official Black Globe (Langston Field) forcefields. Possibly different major races use different types of shield generators...
Plantier Shield generator (characteristics tentative; adjust to fit campaign flavor):
Tech Level: 12+
Size: 40 tons @ TL12, 30 @ TL13, 20 @ TL14,
10 @ TL15, 5 @ TL16+
Cost: MCr 50 @ TL12, 45 @ TL13, 40 @ TL14,
35 @ TL15, 30 @ TL16+
Plantier Shields require a reactionless field-effect maneuver drive (such as gravs or "thruster plates"). The shield generator is an add-on that diverts the drive field strength for protection instead of thrust; trading off maneuver Gs for shield factors on a one-for-one-basis.
Example: A Type T "patrol cruiser" has a 4-G maneuver drive. With a Plantier Shield generator installed, the M-drive can move the ship at 4-G without any shields, at 3-G with Shield-1, 2-G with Shield-2, 1-G with Shield-3, or no maneuvering with Shield-4.
This "one-for-one" tradeoff of maneuver Gs for shield factors is simpler than the calculations needed when using a Black Globe, but tends towards "cavalry charge" tactics in starship combat, where an attacking ship/fleet builds up its speed vectors in the approach and switches to all-shields as it comes within effective range.

From 2300 A.D.

SCREENS
The military protective screen consists of thousands of reflective
foil strips held in a dense protective sphere around the hull by an
electromagnetic field generator. These strips serve to reflect and
dissipate a significant fraction of the energy directed at them.
The strips are not perfectly reflective, however and absorbing
even a small portion of the energy in a laser or particle beam
strike is enough to destroy the reflectivity of the foil strip, which
leads to it being vaporised milliseconds after being struck. It is
thus possible to burn through a protective screen but this reduces
the effectiveness of the weapon so used. Screens do not
stack but redundant screens can be added.
Defensive screens marginally degrade the effectiveness of sensors.
All Sensors skill rolls suffer a DM of –1 when screens are
engaged, including spotting and targeting, when the screens
are in use. At the same times, using screens makes the vessel
more visible to opponents. Add a DM of +1 to opponent sensor
rolls for active sensors only.
Screens subtract their rating from the damage caused by any attacks.
This is before armour is taken into account. Each shot in a
round degrades the screen’s performance, reducing the rating by
one. By the start of the next round, the screen is returned to full effectiveness
by the release of redundant strips. The screen’s operator
can elect to not replenish the screen. A screen carries six reloads.
After the reloads are exhausted, then the screen is degraded without
being replenished. Additional reloads can be carried. It takes one
Combat Round (five minutes) to reload a screen launcher.
Power: Screens use power to maintain the electromagnetic field
that holds the foil strips in place. While using a screen, reduce
stutterwarp speeds by 10% or forego firing energy weapons.
Old Military Screens: These screens are available at TL 11.
Reloads take up 50% the size of the launcher, and cost 20% of
the cost of the launcher.

Just wondering if anyone uses these or similar rules for shields in their Traveller campaigns.


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[F33D]

"From 2300 A.D.

SCREENS
The military protective screen consists of thousands of reflective
foil strips held in a dense protective sphere around the hull by an
electromagnetic field generator. These strips serve to reflect and
dissipate a significant fraction of the energy directed at them.
The strips are not perfectly reflective, however and absorbing
even a small portion of the energy in a laser or particle beam
strike is enough to destroy the reflectivity of the foil strip, "

That's funny. PA's are like machine guns. They shoot heavy metal nuclei at near c velocity. Strips of foil would do next to nothing.

 

[Solomani666]

"From 2300 A.D.

SCREENS
The military protective screen consists of thousands of reflective
foil strips held in a dense protective sphere around the hull by an
electromagnetic field generator. These strips serve to reflect and
dissipate a significant fraction of the energy directed at them.
The strips are not perfectly reflective, however and absorbing
even a small portion of the energy in a laser or particle beam
strike is enough to destroy the reflectivity of the foil strip, "

That's funny. PA's are like machine guns. They shoot heavy metal nuclei at near c velocity. Strips of foil would do next to nothing.

Agreed.
I would only count them as armor against lasers and as chaff against missiles.

 

[F33D]

"From 2300 A.D.

SCREENS
The military protective screen consists of thousands of reflective
foil strips held in a dense protective sphere around the hull by an
electromagnetic field generator. These strips serve to reflect and
dissipate a significant fraction of the energy directed at them.
The strips are not perfectly reflective, however and absorbing
even a small portion of the energy in a laser or particle beam
strike is enough to destroy the reflectivity of the foil strip, "

That's funny. PA's are like machine guns. They shoot heavy metal nuclei at near c velocity. Strips of foil would do next to nothing.

Agreed.
I would only count them as armor against lasers and as chaff against missiles.

Chaff exists to produce a confusing radar return. Itself it does nothing against a missile. When a missile gets close it will just use the overwhelmingly large IR sig of the space craft.

 

[Solomani666]

"From 2300 A.D.

SCREENS
The military protective screen consists of thousands of reflective
foil strips held in a dense protective sphere around the hull by an
electromagnetic field generator. These strips serve to reflect and
dissipate a significant fraction of the energy directed at them.
The strips are not perfectly reflective, however and absorbing
even a small portion of the energy in a laser or particle beam
strike is enough to destroy the reflectivity of the foil strip, "

That's funny. PA's are like machine guns. They shoot heavy metal nuclei at near c velocity. Strips of foil would do next to nothing.

Agreed.
I would only count them as armor against lasers and as chaff against missiles.

Chaff exists to produce a confusing radar return. Itself it does nothing against a missile. When a missile gets close it will just use the overwhelmingly large IR sig of the space craft.

IMTU standard missiles are radar guided.
Between stealth hulls, flairs and suns, IR is too easy to fool to be a standard missile type.


Chaff decreases the missile 'to hit' roll by confusing its radar.
Since I use the 'to hit' effect as a damage multiplier, chaff is ubiquitous imtu.


.

 

[Condottiere]

Ablative armour might be an option.

 

[Solomani666]

Ablative armour might be an option.

Might work assuming that you never land the ship in an atmosphere.

I thing that reflec covers this rather nicely.

 

[Condottiere]

Depends.

It could be streamlined. It could be placed on specific areas which would protect the locations directly underneath them.

They could be targetted at specific weapon systems, like reactive armour against missiles and torpedoes. The classic torpedo bulges could be aimed at meson guns; or torpedoes; and missiles; and particle accelerators.

 

[F33D]

IMTU standard missiles are radar guided.
Between stealth hulls, flairs and suns, IR is too easy to fool to be a standard missile type.

No. Unlike in atmosphere, in space, IR is almost completely impossible to fool. Basic physics.

Now, THAT being the case, lasers as anti-missile fire would be hitting ~100% of the time. With enough laser turrets missiles would never get close to a ship.

 

[Solomani666]

Unlike in atmosphere, in space, IR is almost completely impossible to fool. Basic physics.

Explain the "Basic Physics" please.

 

[Sevain]

Just because space itself is cold does not mean you can not fool IR. If that is what you are referring to as basic physics.

 

[F33D]

Just because space itself is cold does not mean you can not fool IR. If that is what you are referring to as basic physics.

I didn't say that it couldn't be done. Reread what I wrote.

 

[F33D]

Unlike in atmosphere, in space, IR is almost completely impossible to fool. Basic physics.

Explain the "Basic Physics" please.

Not possible here (time & space constraints). There IS a website that attempts to explain it to those who did not study physical sciences at the college level. If you google something like, "there's no stealth in space" you might find it.

Found it: http://www.projectrho.com/public_html/rocket/spacewardetect.php#id--There_Ain%27t_No_Stealth_In_Space

This will explain the basic physics in a way that most High School grads can understand.

 

[Sevain]

There is a difference between Stealth and fooling the weapons lock of an incoming missile. If you toss an incredibly bright object out of your starship's rear hatch you will fool/blind an IR seeker warhead, but you won't make yourself any less conspicuous.

Project Rho is a good resource, but the people who quote it tend towards dogmatic thinking.

 

[locarno24]

True - active decoys can still work; it then becomes a race between how smart the decoy is (to convince the missile it's the original target) and how smart the missile is (to figure out that it isn't).

It's the difference between stealth and sensor-based warfare; for another example, you can probably deliver enough IR energy onto the seeker head of a missile (to 'white out' the sensor) more easily than you can deliver enough energy to cause major damage to the structure of the missile. Still a point defence laser (effectively) but lower energy requirements means higher rate of fire and/or less mass and energy requirements.

The 'cloud of chaff held in a magnetic field' is......yeah. Not so wild about it. I just about forgive the sandcaster as a 'make smoke' weapon, like WWII destroyers.

 

[Condottiere]

Pure heat signature might be a cheap variant missile; a more advanced version might have the position memorized in it's tiny brain during launch, and a predictor programme that activates once it's blinded.

 

[Rick]

Fit a missile with a gravitometer, program it with the characteristic 'signature' of the targets' drive and launch. Should be able to home in through chaff, flares, pretty much anything. Modern day torpedo-launching mine systems can do something similar with submarines (although they use sonar and specific cavitation noises).

 

[Condottiere]

Should have second stage missiles; that will surprise your opponent.

 

[Solomani666]

Fit a missile with a gravitometer, program it with the characteristic 'signature' of the targets' drive and launch. Should be able to home in through chaff, flares, pretty much anything. Modern day torpedo-launching mine systems can do something similar with submarines (although they use sonar and specific cavitation noises).

Increasing the size by?...

Increasing the cost by?...


.

 

[Condottiere]

Travelller missiles have standard sizes, so unless there's a tech level handwavium, the warhead tends to get shrunk to make place for it.