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Plantier Shields - An Alternative to Black Globes

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.

The Plantier Theory was a "what-if" thought- experiment of a Lt. Plantier of the French Air Force c.1953, during the initial "flying saucer" flaps of that period, and became part of French UFO lore.

Basically, M. Plantier (to cut the boredom common on peacetime military posts) speculated about the possible characteristics of a reactionless field-effect drive. Assuming such a drive was possible, what sort of behavior could we expect from it?

He ended up with a very coherent set of performance characteristics, distinctive behavioral signatures, and "special effects" for a reactionless drive system (such as classic space-opera "grav drive" or CT "reactionless thruster plates").

M. Plantier's theory provides a plausible rationale behind high-tech reactionless drives and the resulting "special effects" provide a useful source of "chrome" and "flavor text" for any far-future, space- opera campaign (not necessarily Traveller).

The Truth About Flying Saucers
by Aime Michel
English-language edition (c) 1956, Pyramid Books paperback printings 1967 & 1975
ISBN 0-515-03435-5, Library of Congress Catalog Number 56-6208
Part 3, Chapter 3: "Lieutenant Plantier's Theory"

TL12 was chosen as most of High Guard's screen generators seem to start at about that tech level; rule-of-thumb was that it should be at least two tech levels higher than grav drives. If introduced at a lower tech level (minimum 8-10), Plantier shields will probably be used instead of hull armor; at a higher tech level, armor technology is established as the main defense and the shields merely augment it.

Shield-generator size is scaled similar to the existing High Guard screens -- nuclear dampers and meson screens. The larger the shield generator, the larger the minimum ship size that can use it.

Cost is scaled into the same range as existing High Guard screens, assuming High Guard Alternative 1 (simple armor replacement/ augmentation). If Alternative 2 (Repulsor replacement) is being used, the cost should be higher (possibly up to a factor of 10, in the price range of Black Globes). The smaller and cheaper the shield generator, the more ships can and will use it.

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.

Shield effects (CT, pre-High Guard):

Here, shields either augment or are used instead of hull armor. Shields count as additional hull armor, i.e. reducing the number of hits that do damage:

Shield effects (post-High Guard)

Alternative 1: As pre-High Guard; shield factors count as additional hull armor factors. This allows the shields to act as a cheap augmentation to hull armor. Note that a Plantier Shield factor provides half the protection of a Black Globe factor, but without the side effects.

Alternative 2: Since Plantier Shields utilize grav drive field strength, they act as omni-directional repulsors against incoming missiles, on a one-for-one basis; incoming missiles roll to penetrate the Plantier Shield as if they were facing the equivalent Repulsor factor. This drastically cuts down the effectiveness of nuclear missiles (one of the major ship-killers), forcing energy weapons back into the fore.

Alternative 3: Both the above, together. This is probably too powerful.