Starship Questions

[ZobMan]

Calling ruleslawyers! I have a couple of questions about the starship rules. I know these might be clarified in High Guardt but just wondered how you guys plyed them:

1) When refining fuel on board ship, do you only obtain a certain proportion of the unrefined hydrogen as refined fuel? 1:5 would seem to make sense to me, as if not then everyone would buy unrefined fuel at spaceports and refine it themselves, which seems a bit strange.

2) Is there a maximum distance for ship weapons? 'Distant' at 50,000km or more for some beam weapons for example has no upper limit. Or do you need to spend 50 thrust to get out of the 'encounter zone'?

3) In space combat, it says that 'Damage is resolved after all attacks have been made in a round'. Does that mean all attacks by the ship whose turn it is, or by all ships in the combat?

 

[klingsor]

If I remember correctly in older editions of Traveller fuel processors were not so common as they are now and were not found on the smaller merchantmen that PCs often found themselves with so PCs were less inclined to buy unrefined fuel.

Hydrogen fuel is presumably cracked from water at most ports which does rather beg the question where do the impurities come from?

The big question is I suppose what is unrefined fuel? Skimmed from a gas giant or an ocean and the answer is easy – hydrogen or hydrocarbons and other gases (helium) and quite possibly water vapour in one case and water with impurities (salts, plankton, fish and perhaps an unlucky diver) in the other. The stuff you buy, no idea. At lower TLs quite possibly natural gas of some sort directly from a geological source or produced from hydrocarbons. The image of fuelling a starship from a gasometer is priceless. These fuels are a lot easier to handle than hydrogen though hydrogen is presumably not that difficult to produce if you have adequate power, the problem is storing the stuff.

 

[klingsor]

I think the first edition of Fire, Fusion and Steel made the point that starship combat ranges were in some ways unrealistically large though I cannot recall what values they were assuming. They had use to a slight cheat (gradational focusing I think) to make lasers work at such ranges. On the other hand you do not want the stupidly short ranges seen in some SF television series for dramatic purposes. I found my copy of F, F & S on Tuesday night so I can look it up when I get home.

 

[pasuuli]

1) When refining fuel on board ship, do you only obtain a certain proportion of the unrefined hydrogen as refined fuel? 1:5 would seem to make sense to me, as if not then everyone would buy unrefined fuel at spaceports and refine it themselves, which seems a bit strange.

For simplicity, you get 1 ton of refined fuel per 1 ton of unrefined fuel. Yes it does mean that every player's ship will have a refinery unless the referee somehow stops them.

I think the first edition of Fire, Fusion and Steel made the point that starship combat ranges were in some ways unrealistically large...

Yes. They handwaved "gravitic focusing" as the band-aid fix to that, and allowed referees to ignore said focusing if they wanted realism.

 

[Rikki Tikki Traveller]

To answer #3, it should be after EVERYONE has attacked.

This is to simulate that the rounds are quite long. So, everyone attacks, everyone rolls damage and then next round you cannot use those weapons that were damaged in the previous round.

 

[GypsyComet]

If I remember correctly in older editions of Traveller fuel processors were not so common as they are now and were not found on the smaller merchantmen that PCs often found themselves with so PCs were less inclined to buy unrefined fuel.

Hydrogen fuel is presumably cracked from water at most ports which does rather beg the question where do the impurities come from?

The big question is I suppose what is unrefined fuel? Skimmed from a gas giant or an ocean and the answer is easy – hydrogen or hydrocarbons and other gases (helium) and quite possibly water vapour in one case and water with impurities (salts, plankton, fish and perhaps an unlucky diver) in the other. The stuff you buy, no idea. At lower TLs quite possibly natural gas of some sort directly from a geological source or produced from hydrocarbons. The image of fuelling a starship from a gasometer is priceless. These fuels are a lot easier to handle than hydrogen though hydrogen is presumably not that difficult to produce if you have adequate power, the problem is storing the stuff.

One of the thresholds of starport "quality" is whether it sells refined fuel or not. Given the quantities required, the purification plant required would not be small, and that is an expenditure not all starports can make. Remember, they're only pulling in a few hundred to a thousand credits per visiting ship, so the multi-MCr cost of a big purifier is hardly trivial.

Given the hazards of storing hydrogen, its also possible that many starports *don't*. They store water, or the straight slush off a gas giant (if necessary in a low-water system) until someone needs fuel. If you buy unrefined fuel, they just pipe over what's in the tank. If you buy refined, they route the flow through the inline purifier. The powerplant (for all but TNE and T4) doesn't care, but feeding the high-strung Jump Drive a mash of hydrogen, helium, oxygen, and the occasional krill is asking for trouble.

Why only occasional? I figure the powerplant actually has 1-to-1 purification built in. The fuel feeds go through enough temperature gradients that the stuff the plant needs can be cracked out as part of the process. It is linear and slow, however, so the built-in process can't crack more than the plant is using *right now*. The process is just slow enough, however, that it won't work in Jump drives even if you put the separators in. Why? Do the numbers. Powerplants use (on a scout) 20 tons in a *month*, while jump drives use 20 tons in 5 minutes.

That said, the jump drive reactor runs very, very hot, and a lot of the stuff it is fed ceases to be an issue very quickly, hydrogen or otherwise. Occasionally something in the unrefined fuel feed doesn't vaporize and devolve to mono-proton gas (or get flushed into the jump bubble) instantly, and *that* is when the misjump chance for using unrefined fuel rears its head.

 

[EDG]

We had a lengthy discussion about fuel use and what refinement actually did on the SFRPG boards:

http://www.sfrpg.org.uk/phpBB3/viewtopic.php?f=41&t=251

The immediate thing to draw from that is that realistically, a ton of hydrogen is going power a power plant for YEARS. So the only thing that really uses up the fuel is the jump drive.


What I concluded myself from that thread is that:

In fact, I'd guess that this is the process that goes on in refinement:

1) raw material (water, hydrocarbons, GG atmosphere) is mined/scooped.
2) the raw material is preprocessed to extract hydrogen, deuterium and helium-3 - this is "unrefined fuel". Unrefined fuel contains some hydrogen, tritium, and helium-4 impurities. This can be piped into the reactor but could lead to less stable and less efficient reactions. Unrefined fuel in the jump grid contains elements other than pure hydrogen, which makes the bubble less stable and could lead to misjumps. Note that pre-processors are built into every reactor.
3) If a fuel refiner is present, this can refine the fuel to separate out the deuterium and helium-3 and extract everything else. Refined fuel contains exactly the elements that the fusion reactor needs - deuterium and helium-3 - so when that's piped into the reactor. Refinement also separates out the pure hydrogen, which leads to a stable jump bubble.

The question then is what to do with the waste products... I can imagine that the OTU is full of helium blimps since so many reactors are there producing it

and

Another issue (that I meant to mention in my last post) is that when refining, we surely should be getting less material out than we're putting into it? According to wikipedia, deuterium accounts for 0.03% by weight of all hydrogen in the oceans of Earth, and 0.06% by atom of hydrogen in the atmosphere of Jupiter. So from 1 ton of unprocessed material put into the pre-processor in my system described above, we're getting only 0.3 to 0.6 kg of deuterium? So we'd need about 1700 tons of (mixed hydrogen from) unprocessed water or GG atmosphere to get 1 ton of deuterium?

Helium-3 is even worse, wiki says "(28 ppm of lunar regolith is helium-4 and 0.01 ppm is helium-3)", though I can't find anything that says how abundant it would be in a gas giant atmosphere.

 

[GypsyComet]

We had a lengthy discussion about fuel use and what refinement actually did on the SFRPG boards:

http://www.sfrpg.org.uk/phpBB3/viewtopic.php?f=41&t=251

The immediate thing to draw from that is that realistically, a ton of hydrogen is going power a power plant for YEARS.

The TNE blind spot is showing again. This was changed in 1991, but since too many people go into a blind Virus rage when you mention TNE, pointing out the rest of TNE's changes rarely has any effect.

 

[Paladin]

To answer #3, it should be after EVERYONE has attacked.

This is to simulate that the rounds are quite long. So, everyone attacks, everyone rolls damage and then next round you cannot use those weapons that were damaged in the previous round.

Covers the flight times/simultaneous fire resolution.
And allows for mutual destruction in a round.

 

[pasuuli]

And allows for mutual destruction in a round.

Always a good thing.