Empty fuel tanks?

[rancke]

For an adventure I need a derelict ship found by the PCs to be unable to move due to empty fuel tanks (Not engine damage). I would like it to be possible to have life support running. I absolutely need to have the computer and the internal security systems (and a low berth) running. Is there any problems with that?

At a pinch, I can have the maneuver drives sabotaged instead of the tanks empty, but I'd really prefer not to, since it would contradict previously published information.


Hans

 

[HG_B]

For an adventure I need a derelict ship found by the PCs to be unable to move due to empty fuel tanks (Not engine damage). I would like it to be possible to have life support running. I absolutely need to have the computer and the internal security systems (and a low berth) running. Is there any problems with that?

At a pinch, I can have the maneuver drives sabotaged instead of the tanks empty, but I'd really prefer not to, since it would contradict previously published information.


Hans

Just have emergency back-up power (internal systems only) on. Solar panels?

 

[Hemdian]

For an adventure I need a derelict ship found by the PCs to be unable to move due to empty fuel tanks (Not engine damage). I would like it to be possible to have life support running. I absolutely need to have the computer and the internal security systems (and a low berth) running. Is there any problems with that?

To start with I think low berths use negligable power. And you need to houserule an emergency battery power system for temporary life support.

Which rule system are you using? Someone correct me if I'm wrong but I believe in CT as long as the power plant is running you can maneuver ... and you need the power plant to be running for the ship's computer to be running. Internal security would be part of the computer system.

With MT you could possibly have the power plant running at a very low level to conserve the last dreggs of fuel.

Hmmm ...

The way I would do it is to have the emergency battery power system I suggested above ... kill life support, and have the ship's computer go into hibernation until something reactivates it (passive sensors? airlock being opened?). But it can only stay active for a finite amount of time before the batteries are drained.

 

[rancke]

Which rule system are you using? Someone correct me if I'm wrong but I believe in CT as long as the power plant is running you can maneuver ... and you need the power plant to be running for the ship's computer to be running. Internal security would be part of the computer system.

I'm going to have to use MGT rules. I'm hoping there's enough of a gray area in the rules (which I'm not too familiar with) to allow it.

With MT you could possibly have the power plant running at a very low level to conserve the last dreggs of fuel.

IIRC, in MT life support power requirements are quite low compared to maneuver drive requirements.

The way I would do it is to have the emergency battery power system I suggested above ... kill life support, and have the ship's computer go into hibernation until something reactivates it (passive sensors? airlock being opened?). But it can only stay active for a finite amount of time before the batteries are drained.

Yes, life support has been off line for many years. One of the things I'm trying to decide is if I can let the computer restart it as the PCs' boat approaches, or if I'll have to let them stay weightless and in their vacc suits.


Hans

 

[by_the_sword]

To regain life support, the PC's could mine water from an ice asteroid and melt the water into vapor. Possibly enough breathable air would be released but you might want to filter that water because ice from space probably has all kinds of crazy chemicals in it.

Ice could also be melted down for fuel, no dangerous skimming through gas giant atmospheres. This might take longer than a skimming run but it is slow and sure. Just grind up the ice and shove it into the fuel tanks.

Why wouldn't a ship have a battery back up system? You'd think that batteries in the future would last a hell of a lot longer than they do now. HG-B mentioned solar panels, not a bad idea for maintaining a trickle charge over many years.

You could make gaining access to the ship and restarting the computer a challenge. It could be quite eerie to explore a "dead" ship with no atmo and no gravity. The computer might be in standby mode or it might need a reboot. Don't forget to include a drifting corpse placing it's hand on a PC's shoulder from behind...

 

[Icosahedron]

Answer 1. Use rule #1: Doesn't matter what it says in the book, the Referee is always right.

Answer 2. IMATU I usually have a 'reserve tank'. It's not enough to move the ship (though on one boxcars occasion it was used as a re-entry package to nudge the ship toward the planet and make a softish landing) but it's enough to fire up the ship's systems to carry out repairs.

Answer 3. Let the salvagers crack some Hydrogen from stored water to make their own reserve tank.

 

[Magnus von Thornwood]

Fusion+!

If MgT allows for it and it is canon as of T4, then the low berth, some basic "restart LS" functions and the computer can be powered by one central or even one Fusion+ unit per low berth, basic life support system and the computer to get it all running and to monitor the sensors and to frustrate claim jumpers from entering the ship. :devil:

Otherwise I agree with by_the_sword and Icosahedron.

 

[E.D.Quibell]

For an adventure I need a derelict ship found by the PCs to be unable to move due to empty fuel tanks (Not engine damage). I would like it to be possible to have life support running. I absolutely need to have the computer and the internal security systems (and a low berth) running. Is there any problems with that?

At a pinch, I can have the maneuver drives sabotaged instead of the tanks empty, but I'd really prefer not to, since it would contradict previously published information.

Hans

I'll go from MT because I know the figures/how it works.

So very roughly (assuming a 100 ton vessel):

Basic Env, Basic and Exstend Ls is about 1.5 Mw per 100 tons (give or take)
Anti Grav is about 180 Mw per 100 tons (give or take)
Computers 0.01 Mw (average)
Low berth 0.001 Mw
CPUs for the above (guess of) 20 or 0.04 Mw and double that for security so 0.08 Mw

So Anti grav is out. Leaving about 1.6 Mw per hour.

Batteries are _out_ becuase of the volume requirements for exstended durations. At TL 15 1.6 Mw for 1 hour would need 0.23 kl volume of batteries or 5.5 kl per day.

So assuming a fully efficent Fusion plant giving 6 Mw per KL at 0.003 kl/h fuel load you would need 0.0008 kl/h fuel (assuming 100% efficency of the Power plant). Or 1 kl of fuel for 50 days (give ot take).

As a comparison 1 kl of fuel would power a 400Mw Power plant (standed ish) for 5 hours.

Assuming you don't want this then Basic Env (light and heat) is your biggee making 1.35 Mw ish of your total. If you lose this you lose all life support, so facting this in leaves about 0.1 Mw needed or 0.00005 kl/h.

0.25 kl of fuel will last 208 days or run the hole ship for 80 minuets.

I'd go with minimal power plant activity, no life support, but with computer, internal security and low berth.

If you do this then it's likley that lots of the air will be frozen and floating about in the ship, ready for minture explosions as the players come near it with their high kelvin tempruture vacc suits! Fun for all the familly

Best regards,

Ewan

 

[Hemdian]

If you do this then it's likley that lots of the air will be frozen and floating about in the ship, ready for minture explosions as the players come near it with their high kelvin tempruture vacc suits! Fun for all the familly

Not necessarily (fun though it might be). Check out the film 2010 for an example of a derelict spacecraft: air cold but still good, and a bad smell from a food locker that went bad before freezing.

 

[mike wightman]

Couldn't the salvage team take a portable generator onboard or connect a power supply from their ship to get basic life support up and running?

 

[HG_B]

Couldn't the salvage team take a portable generator onboard or connect a power supply from their ship to get basic life support up and running?

That or, transfer 1 ton of fuel from their ship to fire up the PP

 

[HiverLord]

One other possibility (not sure if it's ever been discussed...) is that the hull could optionally have solar panels built into a small section of it (though this seems unlikely, due to micrometeorite impacts). Or they could be 'hidden' (protected) under a movable panel, brought out only when absolutely needed (and feasible).
Just a thought.

 

[Icosahedron]

If you do this then it's likley that lots of the air will be frozen and floating about in the ship, ready for minture explosions as the players come near it with their high kelvin tempruture vacc suits! Fun for all the familly

Not necessarily (fun though it might be). Check out the film 2010 for an example of a derelict spacecraft: air cold but still good, and a bad smell from a food locker that went bad before freezing.

If the ship has cooled down to deep space ambient (~3K), there will be no air, it will have frozen and condensed onto surfaces in a deep frost.

 

[aramis]

If it's in a system, it won't cool to 3K... it will cool to whatever it's blackbody radiation output and insolation input balance point is. At Pluto, that's likely to be 33-55K, maybe a bit less if shiny. At Earth, much closer to 200K. Near mercury, even if shiny, probably 400K after a year or so... more if dark.

 

[E.D.Quibell]

If it's in a system, it won't cool to 3K... it will cool to whatever it's blackbody radiation output and insolation input balance point is. At Pluto, that's likely to be 33-55K, maybe a bit less if shiny. At Earth, much closer to 200K. Near mercury, even if shiny, probably 400K after a year or so... more if dark.

How do you work this out?

Regards,

Ewan

 

[E.D.Quibell]

If the ship has cooled down to deep space ambient (~3K), there will be no air, it will have frozen and condensed onto surfaces in a deep frost.

And expand very very quickly when you put your high Kelvin Vacc Suited foot on it?

Fun for all the family again

Regards,

Ewan

 

[HG_B]

If it's in a system, it won't cool to 3K... it will cool to whatever it's blackbody radiation output and insolation input balance point is. At Pluto, that's likely to be 33-55K, maybe a bit less if shiny. At Earth, much closer to 200K. Near mercury, even if shiny, probably 400K after a year or so... more if dark.

"The average temperature of the surface of a typical asteroid is -100 degrees F (-73 degrees C)." ~200 K
http://www.nasa.gov/worldbook/asteroid_worldbook.html

A ship at that temp would also show up VERY nicely on IR detectors.

 

[aramis]

How do you work this out?

Regards,

Ewan

energy input is figured per unit cross sectional area.

That is, find the size it would appear if viewed from the sun, and how much area that would be. For a type S as shown in S7, that's between 100 and 500 m², depending upon angle. Split the difference, call it 300.

next, multiply that out by the watts gained from the sun. http://en.wikipedia.org/wiki/Sunlight#Sunlight_intensity_in_the_Solar_System shows the range for earth orbit to be 1.3-1.4kW/m²

So a scout courier can expect some 400kW input.

You then solve Plank's Blackbody equation for I= 1.3kW/m². Which said math is beyond me.



HOWEVER, as a shortcut... Earth's blackbody temperature would be ~ -18°C. That's about 255°K. That's your Hab Zone. (Atmosphere greenhouse effect and internal heat make up the rest.)

Using the temperature estimate for a planet:
Te=Ts√(Rs√((1-α)/є)/(2D))

Temp "earth" in °K
Temp Sun in °K
D orbital distance in m
Rs radius of the sun in m
α albedo (as fraction)
є average emissivity in IR - can be approximated with 1, especially for ships

note that earth's є is less than 1… due to greenhouse effect.
A ship might have an albedo of up to .5 or so...

http://en.wikipedia.org/wiki/Black_body

 

[E.D.Quibell]

Cheers Will,

Regards

Ewan

 

[Icosahedron]

If it's in a system, it won't cool to 3K... it will cool to whatever it's blackbody radiation output and insolation input balance point is. At Pluto, that's likely to be 33-55K, maybe a bit less if shiny. At Earth, much closer to 200K. Near mercury, even if shiny, probably 400K after a year or so... more if dark.

Doh, yeah. For some reason I'd got it into my head that the ship was floating around in an empty hex.