Friday, May 30, 2008


Somebody on CoTI recalled a Keith Brothers reference regarding life support tonnage: they'd figured that it comes to about 10kg per person per week.

that 25 person/months per ton.
figure on crew size, do a little dance, and you've got a warship's logistical tonnage figured.

So a ship with a crew of 25 should have at least 1 ton set aside for life support per month of operations.


Does that seem a little low to you?

I'd been leaning towards something along the lines of 1% of a ship's tonnage per month for logistical supply (and perhaps recreational/sanity space?)
So a 400 ton warship should have at least 4 tons given over to such concerns per month of extended duty; a 1000 ton warship should have 10 tons per month.

Going by the Keiths' assessment, a patrol cruiser should have about a ton. As it is, there's what, fifty tons cargo space there? So that's plenty.


Blogger Omer Golan said...

I'd say that the "standard" life-support load (2 weeks) is subsumed in the stateroom tonnage (which IMHO includes life support equipment, lounges and medlabs in addition to actual staterooms). Anything beyond that would take cargo space.

11:25 PM  
Blogger Sam said...

I like the 10 kgs. This is what is required. Your 1% could be a generous allotment hat included spare parts for extended ops, for everything from vacc suits to entertainment consoles, extra uniforms, droid parts, airlock parts, cleaning supplies, toiletries, sports equipment, seasonal decorations, and various sundries. Just thinking about what would normally be starport maintenance and repair being done aboard.

9:13 AM  
Blogger Craig A. Glesner said...

10 Kg seems a smidge small to me.

I mean it is only about 22 pounds which like a filled to the brim backpack. For one month?

Are they assuming only high tech "space food", flash preserved, just add water or what? Or it mostly staples like flour, rice, beans, some spices, freeze dried meat, etc. (Which still does not account for the water or atmosphere.)

I do love these little questions of Traveller.



7:41 PM  
Blogger Sam said...

10 kgs/person/week works.
(NOT per month!!)Water and atmospheric components are filtered and recycled. 1 kg of (mostly) dehydrated staples is considered good for backpacking; ths is in the nature of flour, beans, rice, cheese, and dehydrated milk, potatoes and the like. The point is, for starship fare, with everything dehydrated, and less (a lot less!) physical activity, it Could go lower, to say .8 kg/person/day. Add filters, and hygene supplies, and you've got your other .6 kg/person/day.

I agree that this is a minimum medium passage life support for the standard 2 weeks. High passage would probably entail another 20 kg / person /week.

Here we get into the issue that the LBB's sometimes got mass and displacement a bit mixed up; how much does that 25 person-months displace? It certainly displaces less than the roughly 14,000 liters of a ton of lHyd, and much more than the 1000 liters of a ton of water.

We could therefore say that a dton of life support would mass 4000 kg, and be good for 1000 person months.

That would not account for logistical suport of the ship.

The beauty of the LBB's, though, was (with certain well-known exceptions) playability. If we said that there were 25 people-months of life support though per dton, massing something like 6,000 kg, for extended journeys away from starports, this might work best.

10:01 AM  
Blogger Craig A. Glesner said...

Okay, per is not so bad, I tend to bring that much on board when I do shopping. Though I can fill a messenger bag and am still carrying stuff. (I got to stop trying to read/post when I am tired.)

Yeah the issue of volume versus mass/weight is always been one of the "fun" parts of Traveller.

4:22 PM  

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