Aslan Bases

[mike wightman]

The cargo ton of CT was explicitly 1000kg. It looks like, as Spinward says, a confusion between a metric ton and an Imperial ton. Note a displacement ton of 14 cubic metres would be able to hold way more supplies than either.

The boxed module Beltstrike corrects this to:

150 person-weeks of life-support supplies take up one ton of cargo space and cost Cr15,000. This amount will support one person far 150 weeks, 3 people for 50 weeks, etc. Life support supplies include food, air and water (to replace leakage from the recycling process), and consumable elements of the fife support system, such as filters, CO2 absorbers, and so on.

 

[Spinward Flow]

Beltstrike, p3 (published 1984)

In long voyages of this type, life support not only costs money but takes up measurable cargo space. Life support costs are paid as in the Traveller rules (Cr2000 per person per 2 weeks, or Cr1000 per week); 150 person-weeks of life-support supplies take up one ton of cargo space and cost Cr150,000. This amount will support one person far 150 weeks, 3 people for 50 weeks. etc. Life support supplies include food, air and water (to replace leakage from the recycling process), and consumable e!ements of the fife support system, such as filters, CO₂ absorbers, and so on.

You dropped a zero from the credit cost per ton @mike wightman ... it's Cr150,000 per ton, not Cr15,000 per ton ... although, now that I look at this more thoroughly, the Cr150,000 may be yet another errata and should have been printed as Cr15,000 per ton as you cite. For one thing, it implies that the true cost of life support is Cr1000 per person/day, which is the equivalent to a middle passage ticket for 8 days of life support alone.

As an additional cross-reference point, LBB3.81 p19 contains the following:

Subsistence on a Long Term Basis: In situations where time passes quickly, personal survival or subsistence costs can be assumed to be the values given below:

• Starvation Level: bare minimum of food, Cr60 per month; dismal lodging, Cr60 per month.
• Subsistence Level: reasonable food, Cr120 per month; acceptable lodging, Cr180 per month.
• Ordinary Level: good food, Cr200 per month; good lodging, Cr200 per month.
• High Living: excellent food, Cr600 per month; excellent accommodations, Cr300 per month.
• Starships: Passengers and crewmembers have their food and lodging provided.

So high living amounts to Cr20 per day (Cr600 per 30 days) for food and Cr10 per day (Cr 300 per 30 days) for housing.
Billing Cr1000 per day for life support on a starship therefore seems excessive (one month of high living outside a starship is cheaper than the life support costs for that same person aboard a starship?). By contrast, billing Cr100 per day (3.3 days of high living outside a starship is approximately the same cost as life support aboard a starship) makes a LOT more sense.

Note that this reference gives us a very direct correlation between (single occupancy) stateroom life support costs and how much of the 4 tons for that stateroom ought to be devoted towards providing 2 weeks of life support in that stateroom context.

1 ton of life support reserves = 150 person days = Cr150,000
4 ton single occupancy stateroom = 14 person days = Cr2000

14 days / 150 days = 0.0933 tons
2000/150,000 = 0.01333 tons = 1.9995 person days (that's not enough to last through a 7 day jump!)
2000/15,000 = 0.1333 tons = 19.995 person days (enough for 2 weeks +42.86% reserve margin)

Getting these two results to reconcile/match requires assuming that stateroom life support (Cr2000 per 2 weeks) actually equates to 20 person/days ... which is functionally a +43% reserve margin over 2 weeks/14 days ... and that reserve life support costs Cr15,000 per ton which amounts to Cr100 per person/day.

20/150 = 0.1333 tons

So essentially a situation where although the stateroom life support says it is being billed at a Cr2000 per 2 person/weeks rate for replenishment, it's ACTUALLY a Cr2000 per 20 days rate for replenishment, with the idea being that 14 days is a two week interstellar merchant jump cycle (1 week in jump, 1 week out of jump conducting business, maneuvering to/from jump points, etc.) leaving an extra 6 person/days of life support capacity in reserve in the event of mishap or disaster.

Such a formulation makes a lot of sense from a Search & Rescue/Disaster Recovery perspective in terms of safety regulations and requirements. It means that after jumping, a starship ought to have anywhere from 6-14 days of life support capacity for rescue teams to maneuver to lend aid and assistance to a disabled starship that is unable to recover itself (assuming a distress signal can be sent).

Referencing the Interplanetary Travel Distance by Time and Acceleration charts I made this past year, 5 days of acceleration/deceleration maneuvering to rendezvous with a disabled starship yields the following matrix of ranges:

• 1G = 3.118 AU
• 2G = 6.237 AU
• 3G = 9.356 AU
• 4G = 12.474 AU
• 5G = 15.593 AU
• 6G = 18.712 AU

In other words, with only 6 days to maneuver to a rendezvous for a rescue attempt, if 5 days are spent maneuvering into position for that rendezvous, allowing an up to 1 day margin after the distress signal was sent, depending on the maneuver drive power of the rescue ship the above ranges represent "how far" such a rescue ship can travel and still arrive in time to stabilize the disabled ship and provide relief before life support reserves aboard the disabled ship expires (along with the passengers and crew, presumably, for lack of life support).

Note that the same assumptions would also apply to interplanetary small craft (assuming they have Cabins for life support extension beyond 12 hours of combat or 24 hours of routine operations, which is the life support limit for acceleration couches).



And now that I've done that bit of cross comparison analysis ... I think I may need to update and revise a lot of my previous starship designs with some slight tweaks to them such that they incorporate this newly discovered (thanks @aramis and @mike wightman ) to more "properly" extend their endurance not just through adding extra fuel for additional parsecs, but also additional life support reserves in the "fraction of a ton" otherwise wasted space incorporated into their designs. Let No Tonnage Be Wasted (and all that).

And guess what? This means that my 5-6G maneuver drive Courier starship designs get to have yet another potential role (besides mail courier, merchant, fuel tanker, colony support transport, long range scientific explorer/survey researcher, etc.) as possible interplanetary Search & Rescue ships able to vector away at high acceleration for rescue ops in star systems without a shipyard that can construct/maintain local small craft for the task (so a jump drive will be needed to get to a shipyard that can perform annual maintenance at a type A/B starport outside the system).

Additionally, as a side effect of doing that, for the starships with more powerful maneuver drives, by taking less time to maneuver to and from jump points they would, over a succession of jumps, require less person/days of life support upkeep, creating a small savings opportunity for the absurdly cost conscious operator (faster maneuvering means lower consumption of life support consumables). Depending on how detailed you want to get as a referee, if you're taking it all the way down to the person/days level of life support overhead you can start pinching a few credits here and there (which will add up over the 40 years of a starship's designed lifespan) to squeeze out just that little bit more profit margin from time to time.

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Yet another side note ...

Low berth life support costs are Cr100 per berth (for 2 weeks).
At Cr15,000 per 150 person/days per 1 ton ... that functionally equates to a Low Berth needing the equivalent of 1 person/day of life support consumables per 20 days, when using the above understanding for starship stateroom life support equivalencies.

 

[mike wightman]

You can blame that on the poor quality of the OCR...

 

[whartung]

1000kg in 14m^3 is only 71g/liter, which isn't a lot.

Styrofoam is about 14 times more dense.

 

[Condottiere]

Seems too complex to handle this ad hoc, hence sticking to volume.

You could construct the spaceship out of aerogel aluminum, but we do use bonded superdense as armour, so on a cubic metre basis, that's probably incredibly heavy.

 

[Dragoner]

I have generally used 250kg per m^3, or 3.5 tons mass per Traveller's dton; one can easily round up and be 4x, it remains good enough for napkin math.

 

[Condottiere]

One difference would be transporting a tonne of gold, and a car.

I think under the Mongosian algorithm, that's three tonnes of shipping space, compared to so the volume of one tonne (1000 kg) of Au would be 0,0517598343685 m³ or 51.76 litres. That is a cube of 37.26 cm per side.

 

[Spinward Flow]

1000kg in 14m^3 is only 71g/liter, which isn't a lot.

Styrofoam is about 14 times more dense.

I shouldn't have to say this (mainly because @aramis already did), but ...

1000kg occupying 14m³ is the density of Liquid Hydrogen.

Liquid hydrogen is notoriously low density in comparison to other matter.

Styrofoam and liquid water are 14x more dense than liquid hydrogen.
Doesn't change the fact that 1 ton of liquid water occupies 1m³ ... while 1 ton of liquid hydrogen occupies 14m³.
And 1 ton of gold occupies 0.518m³ ... because gold is a dense precious metal (specific gravity 19.3x the density of water).



When it comes to starship tons capacity ... the correct answer is 14m³ of volume *OR* 1000kg of mass, whichever threshold you meet first.

That way if you have something with a density lower than liquid hydrogen, 1000kg of that matter can occupy more than a single starship ton because the volume required is more important than the mass in that case. This kind of situation can easily happen if you need to enclose an object that doesn't have a simple geometric "box" shape (such as, say, an aircraft with wings that do not fold) and you wind up with a lot of "wasted empty space" around the item.

For example, a Saab JAS 39 E Gripen fighter jet (in the real world) has dimensions of 15.2m long, 8.6m wingspan, 4.5m height and a dry mass of 8000kg.
15.2 * 8.6 * 4.5 = 588.24m³ / 14 = 42.02 starship tons

So how much cargo space would such an aircraft need (minimum) in a starship cargo hold if it was fully assembled in a flyable condition tied down inside the cargo hold?

Easy answer ... 42 tons of cargo space ... not 8 tons because the fighter weighs 8000kg dry.

Conversely, if I needed to ship 3000kg of aluminum, despite the fact that such a material would only occupy 1m3[/sup] of volume a full 3 tons of cargo capacity would need to be devoted to transporting that material.



Remember, the rule you want to be using for starship tons is 14m³ of volume *OR* 1000kg of mass, whichever comes first, is the limit per ton for cargo capacities. That way, starship "tons" can be fungible between volume or mass as the critical determining factor somewhat interchangeably.

 

[whartung]

When it comes to starship tons capacity ... the correct answer is 14m3 of volume *OR* 1000kg of mass, whichever threshold you meet first.

Limiting 14m3 to 1000kg is about half the density that a 747 can take.

I would expect a starship not limited by wing lift to be able to take more weight/liter.

 

[mike wightman]

Every iteration of CT agrees on this point - one cargo ton is 1000kg.

 

[Condottiere]

Yes, that is as dilemmic as me carefully weighing each bag before leaving for the airport, and High Passage ticket holders dragging along a tonne of luggage.

 

[Spinward Flow]

High Passage ticket holders dragging along a tonne of luggage.

That 1 ton of luggage is only a problem for a starship if that luggage is ... liquid hydrogen ... (and if it is liquid hydrogen, it's probably stored in the fuel tanks, not the cargo hold).

If the luggage is something denser than liquid hydrogen (like, say, clothes and snacks and personal items) then even if those items are only ONE QUARTER the density of H₂O liquid water, you're still only looking at needing 4m³ of space to store 1000kg of them in ... which wouldn't you know it will fit into a 1.5m x 1.5m x 2m = 4.5m³ volume of closet space within a stateroom (as opposed to stuffing that luggage into the cargo hold that passengers probably won't have access to).

Point being that a single 1.5m by 1.5m deck plan square in a stateroom can easily supply sufficient "closet space" for most if the 1000kg baggage allowance that high passengers might need (and if that's not enough, then two squares of deck plan space in the stateroom almost certainly will ... meaning, that if high passengers need "extra space in the cargo hold" for their luggage, they can purchase that extra cargo space just like anyone else needing to transport cargo (that won't be accessible during the trip).

 

[aramis]

Every iteration of CT agrees on this point - one cargo ton is 1000kg.

It also says (in the more recent, thus, per Marc, more authoritative) 81 and 82 rules editions that 1 ton is 2 squares 1.5×1.5×3m. (B2 p 21) Said location also affirms 14 cubic meters per ton.

It's safe to assume the CT Cargo Ton is a combined unit of 1 tonne and 14 m, if one really must, but the ship ton is 14 cubic meters, and cargo space is in ship tons in the design sequence.

 

[BlackBat242]

I would also expect that only some of the refugee fleet will be configured for max passenger transport... a similar number would carry only the crew with the rest of the assignable volume devoted to cargo.

Giving them a lot more equipment for building that colony than someone seems to be willing to admit.

 

[mike wightman]

I wouldn't take much cargo on such an extended mission. Space is full of the raw materials you need to feed manufactories - makers.
Designate a few of your ships as agricultural manufactories and they can produce all the food needed for the colonists, you also need a couple of industrial manufactories to make the spare parts for the ships. You will need resource gatherers - although these can be smallcraft.

With such a set up you don't really need to worry about building colonial infrastructure at your destination, you have the tools needed to build it from the raw materials you find there.