Gurps traveller refuelling question

Wylie wrote:
> Just read the news article on our new brown dwarf neighbor and it got
> me wondering: Can a Traveller ship with fuel scoops refuel from a
> brown dwarf?
>
> The article indicated the dwarf had a temp of about 750 degrees cent,
> but I would imagine it would be much cooler in upper atmosphere.
>

I imagine the problem wouldn't be the temperature, but the intense
gravitational field. So it would depend on the exact size of the brown
dwarf; only if it was pretty small (not too much bigger than a big gas
giant planet).

--
Aaron Boyden

"I may have done this and that for sufferers; but always I seemed to
have done better when I learned to feel better joys."
-Thus spoke Zarathustra
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> Personally, I would say that it would not be possible without special,
> expensive adaptations made to the fuel scoops and processing plant in
> order for them to withstand the greatly increased temperatures. The
> surface temperature of Jupiter is about 160 K. The surface temperature
> of your brown dwarf is about 1025 K. And then there is the extra heat
> generated by the friction of scooping in the hydrogen.

Yeah, one brown dwarf might have a high surface temperature, but they
generally cool with age - no fusion reactions to keep them warm, right?

The escape velocity would be a pain, though. But where you have brown
dwarfs, you'll probably have water-bearing moons, debris, etc. nearby.
Just mine the moons of the brown dwarf. Look at Jupiter and its
ice-stuffed moons.

Mike Miller, Materials Engineer
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Cray74.DeleteThis@gmail.com wrote:
> > Personally, I would say that it would not be possible without special,
> > expensive adaptations made to the fuel scoops and processing plant in
> > order for them to withstand the greatly increased temperatures. The
> > surface temperature of Jupiter is about 160 K. The surface temperature
> > of your brown dwarf is about 1025 K. And then there is the extra heat
> > generated by the friction of scooping in the hydrogen.
>
> Yeah, one brown dwarf might have a high surface temperature, but they
> generally cool with age - no fusion reactions to keep them warm, right?

Right. But with age, they also shrink, which keeps them hat through
gravational heating. That is the same reason that Jupiter is warmer
than it should be for its distance from the sun.

>
> The escape velocity would be a pain, though. But where you have brown
> dwarfs, you'll probably have water-bearing moons, debris, etc. nearby.
> Just mine the moons of the brown dwarf. Look at Jupiter and its
> ice-stuffed moons.
>
> Mike Miller, Materials Engineer

That makes perfect sense. However, the question was with respect to
the brown dwarf itself. So that is what I addressed.

Mark Sebree
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HI! I was club sec'y of the Strategic Games Society, at CU, Boulder,
lo, years ago. I played Traveller, & in our Improvised Star Wars
campaign Moffs who needed fuel & weren't shy about breaking the
POLLUTION laws would refuel at poorly organized stars possibly
including; BROWN DWARFS! (The output tended to be a LOT more
Radioactive than normal)
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Sorry, not too familiar with astrophysics. Would a brown dwarf,
particulary a rogue, likely have moons?
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Wylie wrote:
> Sorry, not too familiar with astrophysics. Would a brown dwarf,
> particulary a rogue, likely have moons?

Actually, yes. The same forces that create the stars and the planets
would also create planets/moons for a brown dwarf. It is not likely
that they would be very large, however. In fact, most of its system
would likely resemble a series of asteroid belts and comets.

And a rogue star is likely to have rogue planets/moons, simply because
it is rogue. It travels in a manner different from the surrounding
stars, and thus crosses their paths. Most of what it would pick up
would Oort cloud and cometary material, but extra planets could be
captured as well.

Mark Sebree
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Wylie wrote:
> Just read the news article on our new brown dwarf neighbor and it got
> me wondering: Can a Traveller ship with fuel scoops refuel from a
> brown dwarf?

I'm sure a GTL 13 ship could. Maybe not your average(!) GTL 13 ship, but
at that TL, if you want to you should be able to build fuel scoops and a
fuel refiner that can handle the heat. And a hull/armour coating.

As for lower TLs, I'm not sure. GTL 12 is impressive too, although the
jump from GTL 12 to GTL 13 is much starker than jumps between lower GTLs.

> The article indicated the dwarf had a temp of about 750 degrees cent,
> but I would imagine it would be much cooler in upper atmosphere.

--
Peter Knutsen
sagatafl.org
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years ago i read an article in a traveller magazine about how various
tech items worked. it was part of a series introducing players to the
basic idea of how various items worked and one covered their fusion
power plants.

they were kind enough to point out that they only "burned" the
deuterium and tritium in the hydrogen they scooped up with the vast
majority being just a waste product. this caught my attention as any
way to bring down the fuel tank size in traveller is worth it's weight
in irridium at the very least. well lo it turns out that if you can
separate out the d and t from the plain old hydrogen you can reduce
your tankage by oh 99% while carrying enough fuel in a 45 gallon drum
to run a battle wagon for months and jump at will during that time.

didn't say a word about this to the long suffering gm until i got a
chance to put this into practice with a ship of my own. the look on
his face when i explained things to him was just priceless. even had
a copy of the article to back up what i was saying.

separating the fuel in the boonies isn't at all practical but
considering the amount of jump fuel you can carry about having to stop
and top up every few years isn't such a big hassle. i got an utterly
obscene check from the imperial navy when i explained how to "fix" a
huge logistical hole for them as well as opening up new vistas of much
tougher warships. the glory days.
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On Fri, 24 Mar 2006 02:10:13 GMT, forkliftramp.com
<Brian_knowspam.McDonald DeleteThis @shaw.ca> wrote:


>didn't say a word about this to the long suffering gm until i got a
>chance to put this into practice with a ship of my own. the look on
>his face when i explained things to him was just priceless. even had
>a copy of the article to back up what i was saying.

And he was dumb enough to fall for that?
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forkliftramp.com wrote:
> years ago i read an article in a traveller magazine about how various
> tech items worked. it was part of a series introducing players to the
> basic idea of how various items worked and one covered their fusion
> power plants.
>
> they were kind enough to point out that they only "burned" the
> deuterium and tritium in the hydrogen they scooped up with the vast
> majority being just a waste product. this caught my attention as any
> way to bring down the fuel tank size in traveller is worth it's weight
> in irridium at the very least. well lo it turns out that if you can
> separate out the d and t from the plain old hydrogen you can reduce
> your tankage by oh 99% while carrying enough fuel in a 45 gallon drum
> to run a battle wagon for months and jump at will during that time.
>
> didn't say a word about this to the long suffering gm until i got a
> chance to put this into practice with a ship of my own. the look on
> his face when i explained things to him was just priceless. even had
> a copy of the article to back up what i was saying.
>
> separating the fuel in the boonies isn't at all practical but
> considering the amount of jump fuel you can carry about having to stop
> and top up every few years isn't such a big hassle. i got an utterly
> obscene check from the imperial navy when i explained how to "fix" a
> huge logistical hole for them as well as opening up new vistas of much
> tougher warships. the glory days.


I saw another article that showed that unless the power plants and
engines were 100% efficient that there was no way that a star ship would
survive more than a couple of seconds before being vaporized by the
excess heat. Look at the unused hydrogen atoms in the fuel being used
to dump the excess heat from the power plants and engines.
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Jefferson wrote:
> Michael W. Ryder wrote:
>
>> I saw another article that showed that unless the power plants and
>> engines were 100% efficient that there was no way that a star ship
>> would survive more than a couple of seconds before being vaporized by
>> the excess heat. Look at the unused hydrogen atoms in the fuel being
>> used to dump the excess heat from the power plants and engines.
>
> That . . . actually makes sense -- but I suspect that if dumping heat is
> the point there's a more efficient way to go about it.
>

I think the hydrogen was used as it was cheap and easy to get. There is
not enough mass in a starship to use it as a heat sink with even 99%
efficient power plants.
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David Johnston wrote:
> <Brian_knowspam.McDonald.TakeThisOut@shaw.ca> wrote:
>>didn't say a word about this to the long suffering gm until i got a
>>chance to put this into practice with a ship of my own. the look on
>>his face when i explained things to him was just priceless. even had
>>a copy of the article to back up what i was saying.
>
> And he was dumb enough to fall for that?

Massive hydrogen consumption is a *fact* of the Traveller setting,
trying to circumvent it entirely is moronic.

Even reducing the fuel consumption from 10% of ship's volume per parsec
to like 8-9% per parsec would be a *gigantic* scientific breakthrough.

--
Peter Knutsen
sagatafl.org
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David Johnston wrote:
> On 23 Mar 2006 19:17:09 -0800, "Mark Sebree" <sebree DeleteThis @infionline.net>
> wrote:
>
> >
> >Jefferson wrote:
> >> Michael W. Ryder wrote:
> >>
> >> > I saw another article that showed that unless the power plants and
> >> > engines were 100% efficient that there was no way that a star ship would
> >> > survive more than a couple of seconds before being vaporized by the
> >> > excess heat. Look at the unused hydrogen atoms in the fuel being used
> >> > to dump the excess heat from the power plants and engines.
> >>
> >> That . . . actually makes sense -- but I suspect that if dumping
> >> heat is the point there's a more efficient way to go about it.
> >
> >In space? Not really. A vacuum is an insulator. Some of the heat
> >will radiate away, but not enough to do much good. The most efficient
> >way is evaporative. Let a cold gas absorb as much heat practical, and
> >then exhaust the gas from the ship.
>
> Now that's an interesting thought. Means that as the ship jumps it
> leaves a massive plume of hot waste hydrogen/Helium and even as it
> manuevers it leaves a trail that could be followed.

I've heard of many different ideas as to where all the hydrogen goes.
One I particularly liked way back when was that the hydrogen was use to
create a "bubble" in jumpspace that the ship is inserted into.

Of course you are best off just ignoring the explanation and stating
That's Just How It Works. No one seems to need an explanation for how
all the contragravity stuff works so why the jump drives?
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