2 Days of Fuel Left

[atpollard]

How much more CO2 does a person in the 23rd century exhale compared to a person in the 20th century?

How much more food and water/waste does a person in the 23rd century consume/produce compared to a person in the 20th century?

How much more energy does a 23rd century LS system require per person compared to a 20th century LS system?

The LS load per person is the same. The amount of energy required by the more capable High Tech system might be greater (that argument could go either way) but it will probably not be tens of millions of times greater.

1 EP output = 250 MW = 250,000 kW
Apollo LS requires about 7 W = 0.007kW = 0.00000003 EP per person
Assuming 23rd Century LS = 7kW = 0.00003 EP per person

One EP output for 1 second would generate about 69 kWh, so one second of output would support 9 people for 6 weeks at the 7W power level or 9 people for 1 hour at the 7kW power level. Even at the higher power level, LS requires running the PP for 1 second every hour to sustain a 9 man crew.

 

[aramis]

The apollo system is purely lights, circulation and heat. Everything else LS based was essentially unpowered. The O2 was purely stored, not cracked. The CO2 removal was by pure chemical binding means. The water was in a presurized tank, and the toilet vented to vacuum.

Circulation, light and heat are purely volume issues, not per person issues.

Cracking the CO2 is FAR more energy. distributing the resulting oxygen is a function of volume; a scoutship is several dozens of times more volume.

Borrowing the numbers from MT:
Stateroom: 2kW
Extended LS, per kL: 2kW, needs BLS
Basic LS, per kL: 1kW, needs BEnv
Basic Env, per kL: 1kW
Net: 4kW per kL + 2kW per person.

I think that the environment numbers are a bit high.
The BLS numbers only make sense if it's cracking, not just tank-releasing & circulating.

A 1000 cfm fan draws about 18w. That should be good for circulating 20Td of air. (IIRC, target exchange rate is ideally 100% per 10 minutes.) realistically, that's 1w/Td
A 1kW heater is good for about 8x12x10', or roughly 1000cf. so that's 1kW per 2 Td.
Lights, using LED, should be about 5-10w/Td.
So BEnv should be 511w/Td.

That puts BEnv at 28x real world. Add an ionizing filter, add another 100w/Td.

The BLS needs to add CO2 removal and Oxygen increase, plus water removal. (which said water removal adds also the option for providing potable water.)

 

[Andrew M]

Cut bits off your ship and chuck them out the window!

Okay, this is a mainly completely if not totally comlpetely unfeasible solution, but I don't think people have gauged just how deadly the situation described is. On pretty much any ship the jump drive will soak up over 70% of the fuel requirements and on all ships it takes up 10% of the ships mass. The main problem is not life support, that's peanuts compared to just getting back to realspace.

There are many reasons why ditching mass is unfeasible, but that it might just work..

Against Your craft is incredibly well constructed, put together over a period of months by a team of experts having to hand all the facilities a TL 13+, class A Naval dockyard can provide.

For You have access to state of the art military hardware furnished by the self same Naval dockyard, capable of taking apart enemy ships hundreds of kilometers away. All you need is some way to aim it right.

Against Those navigation calculations that you made assumed you had 200tonnes of mass. Coming out of hyperspace with anything less than this is going to make a misjump inevitable.

For Yes but you are desperate.

Against Just because you can chop bits off your ship does not mean you can get them far enough from the craft that they won't soak up fuel anyway. If you have a jump grid, presumably that stops anything getting in or out, otherwise what use is it? Otherwise, the chances are your bit of jumpspace will be folded in on itself so that anything you chuck out portside will come straight back at you from starboard.

For But, what else are you going to do, sacrifice a crewmate to the elder gods?

Against That is starting to sound like a good plan.

For You can always do both.

 

[far-trader]

...If you have a Type-S Scout ship built using High Guard rules, at Tech-15, the Power Plant-2 fuel is only two tons (2 kiloliters)...

Small correction, a Traveller "ton" is 13.5kl or 14.0kl depending on the rule set, so the two tons of fuel is 27.0kl or 28.0kl meaning just ~33 hours of fuel for power (if you don't save any for drinking) from that stateroom allowance.

Otherwise I like the idea, if:

1. There's actually that much water held in reserves aboard the ship. I always thought the reserves were very low and there was a lot of recycling done by the LS (exhaled moisture condensed, waste water purified, etc.).
2. The powerplant is capable of being fed such small (inconsequential even) quantities of fuel and actually use them with the same efficiency. Imagine trying to run a small gasoline engine by dripping a few drops of fuel into the tank for example.

 

[robject]

There are many reasons why ditching mass is unfeasible, but that it might just work..

Against [...]

For [...]

Turn this into a fictional conversation between two NPCs and you've got some entertaining-while-also-informative reading!

 

[rancke]

Okay, this is a mainly completely if not totally comlpetely unfeasible solution, but I don't think people have gauged just how deadly the situation described is. On pretty much any ship the jump drive will soak up over 70% of the fuel requirements and on all ships it takes up 10% of the ships mass. The main problem is not life support, that's peanuts compared to just getting back to realspace.

Getting back to real space is automatic. It doesn't take any energy at all. At the end of the trip, you get precipitated out of jumpspace willy-nilly.


Hans

 

[Andrew M]

Turn this into a fictional conversation between two NPCs and you've got some entertaining-while-also-informative reading!

I am not so sure about informative, but thank you. I think it shows how good storytelling and inescapable doom can work together.

Hans is of course right about the certainty and willy-nillity of a return to realspace.