Monday, June 2, 2014

Jump Starting the Jump Drive

Continuing my tinkering with Traveller for a near future setting.

The facts:
Humans have recently begun expanding into space via FTL, bringing them into conflict with colonists who arrived at their colonization targets decades ago via STL.

The average TL is 9. 

I'd like to use a minimum of material outside the LLBs.

The LBBs make TL 9 drives too good.

LBB 2 allows you to build G rated drives at TL 9. This allows you to construct a 400 ton ships with Jump 3. This is minimum TL for having a starship. J-3 is too darned good. I need to restrict it to J-1 to force people to use rogue planets and icy blobs between the stars (which are themselves colonized in some instances.) My options as I see it:

1) Use High Guard style drives. Possible, but I already stated my intention.

2) Restrict the Jump programs available to J-1 or increase the number of programs necessary to Jump.

3) As the first Jump Drive produced this beast guzzles fuel requiring refueling after each jump. Fuel use is 4x normal. A ships can store enough fuel for a jump one way and still have drives and a useful payload.

On reflection I decided to go with option 3 as Traveller canon said the first Terran J-drives were fuel guzzlers and this requires ships to stop and refuel. It also makes early FTL travel similar to current space travel. Fuel hungry vessels with mass at a premium. If I use the High Guard rules for power plant fuel (.01 Mass * PN instead of 10 * PN) I can use some Book 2 designs with some mods. This also suggests some interesting designs and secret projects. There are differences between Book 2 and High Guard. High Guard limits hull sizes by the model of computer. Book 2 limits it by the drives available. Using the table in Book 2 I can see I can build ships up to 1000 tons. That's fine. The huge ships of 3I don't fit in this setting.

Besides the fuel hungry disadvantage I want jump drives to be a little less dependable. The unmodified throw for a misjump is 11+, not 12+. Missing annual maintenance and using unrefined fuel becomes a bit more risky. Ships usually have low berths equal to the number of occupants just in case a misjump sends you out where no one has been and cooks your drive.

Low Berths
Low passage is more dependable than in the standard rules. Maybe you'd get convicted criminals or fugitives from justice to take a low passage with a 1 in 6 chance of dying but few others would be interested. If the passenger fails the throw for revival they take 2d of damage. The next time they fail a throw for revival and every time after that they increase the damage done by 2d. Thus failing your save once may leave you under the weather a few days. Failing a second or third time means a hospital stay at least. Four or more mean your characters is probably being fitted for a halo.

One low berth on each ship is fitted with a damage control station and called the Crisis Berth. Its occupant (usually the ship's engineer is placed in the berth wearing a form fitted spacesuit. This occupant is wakened in the event of a catastrophic event. His duties are to make immediate repairs and wake the rest of the crew if necessary to evacuate or help damage control efforts. A Crisis Berth weighs 1 ton and costs 250,000 cr.

Low Power Usage
Ships coasting between the stars typically are kept just above freezing and depressurized. Grav plates are turned off. In this mode 1% of fuel will sustain the ship for about 8 years or a trip of 2 parsecs. It take about 15 minutes for a ship to power up. Sensors and computer functions are kept to a minimum.

TL 8 Sleeper Ships
TL 8 ships do not have artificial gravity and must spin sections of the ship to create g forces. Many of these vessels were converted into space stations and their drives moved to newer and smaller interplanetary ships.

Next: Ship Redesigns.