Ice Refuelling

[whulorigan]

Hmm, according to the last astronomy book I bought (back in 1991 or 1992), both Uranus and Neptune were speculated to have an "ocean mantle"; i.e. a rocky core surrounded by water that is many many miles deep.

Yes, exactly.

At the top of the clouds (ionosphere?) the temperature for both worlds is around 58 to 57 K. That's cold! Which leads one to speculate about the "biosphere"; i.e. the surface of the ocean; is there a hard frozen surface that is constantly cooled, or is there a tumultuous massive ocean there that is constantly whipped into a frenzy by mach 1 winds?

Note in your 2nd (Uranus) diagram, the "surface" is being designated as the interface between the gaseous atmosphere and the liquid mantle. The ocean-surface is noted as having a temperature of 2300^oC (unless I am misreading the diagram). The atmospheric height above the liquid mantle in the Uranus diagram is also less than the atmospheric height in the Neptune diagram, meaning that Neptune has much more atmosphere above its liquid-mantle "surface", and therefore, higher surface pressure than Uranus.

Now, of course, a Neptunian exo-planet need not be similar to either of these.

Loose tangent; the rules as to how much pressure a starship can take would seem to allow a type S 100 ton scout to land on a Neptune or Venus, though it would be a very rough ride once you were down.

Which ruleset are you referencing?

Loose tangent 2; per my previous reference to Venus to clarify astronomical jargon, here's a cleanup processed picture from the Soviet Mariner probe;

Mariner was a NASA probe series; The corresponding Soviet program were the Venera probes. The pictures above look like they came from Venera 9 or 10.

 

[esampson]

I see cool role-play situations where vibrating ice cutters/chompers cause an avalanche on top of the parked ship. Or a star is rising and causing the ice to crack and spray jets from the cracks. The weight of the ship, and the increasing slope of the ice drift your on, is not helping things.

Ice worlds are generally going to have a lower gravity than Earth due to their lower density since they typically lack the heavier elements of rocky bodies. This isn't a given, however, since you could have situations such as a faux-ice world where it is primarily a rocky Earth sized body under a skin of ice that is a hundred kilometers deep.

Assuming there's a lower gravity that would have an impact on avalanches. Of course lower gravity would also make towering ice spires much more likely as well without all that pesky gravity to pull them flat.

On a world where the star is close enough to cause the ice to crack and jets of ice to spray into the air I would imagine a savvy scout would simply use the scoops to pick up the ice particles rather than landing. Players might not think about that since they don't have the skills and knowledge of a trained scout but that might be one of those cases where the ref steps in to give advice since their characters would know more than the players.

 

[Blue Ghost]

DOH! I meant Venera. I get the two confused.

Rules I refer to are CT, and more or less "The Secret of the Ancients", which is either adventure 12 or 13. There's a chart in there describing crush and operational depths for starships in jovian atmospheres. To me it's a "broken rule", but that's just my knee jerk reaction, because any group of players with access to any kind of starship need not worry about stresses on the hull unless they're going really deep in a Saturn or Jupiter like world.

Even though the temperature on an "ice giant" may be 2300 Celsius, according to the rules, the combo of pressure and temp is well within the operational tolerances of the ship. This means even frail things like antenna, sensors of all kinds (pitto tubes), can withstand the near liquid inferno of a Venusian atmosphere, or the "icy hot" ocean of a Neptune or Uranus. I started a whole other thread on that topic alone, and will leave it there.

I think I actually confused Neptune with one or both of its moons. But then I saw a doc about Neptune's weather, and I think I wrongfully derived that there was a solid surface on Neptune. I then had visions of a group of players / adventurers landing on such a hellish world while water and ammonia shards with the consistency of diamond blazed away at their ship's hull and ATV while they went out to find some Ancient artifact....hell, I may still write that one up

But, to the point here; I think the plausibility of landing on a world that is highly uninviting should not deter the possibility of having to brave such an excursion (assuming proper planing).

How you'd refuel from one of these things, other than atmospheric skimming, is beyond me. But it sure would be interesting to see someone try.

Ice at 2300 C? Amazing.

 

[whulorigan]

Ice at 2300 C? Amazing.

If you are at all interested, take a look at the wikipedia article on "Ice" and scroll down to the "Phases" section. It lists all 17 different forms of water-ice and has a graph showing under what conditions (temperature/pressure) they are stable.

http://en.wikipedia.org/wiki/Ice
(Note that 1.0 atm of pressure [= 1.0 bar] is about 100 kilopascals [kPa]).

 

[Blue Ghost]

I remember phase diagrams from my material science class, and most of what we were dealing with were different phases of steel with various applications of heat. It was entertaining and a real eye opener as to what kind of material holds up against what kinds of energies.

 

[Blue Ghost]

How refuel your ship, and protect your back on an ice moon.

http://www.youtube.com/watch?v=lp_Rwbp8S1k

 

[Blue Ghost]

I see cool role-play situations where vibrating ice cutters/chompers cause an avalanche on top of the parked ship. Or a star is rising and causing the ice to crack and spray jets from the cracks. The weight of the ship, and the increasing slope of the ice drift your on, is not helping things.

Hey Shonner, I meant to reply to you, but got sidetracked with the whole Neptune thing.

I like the example you and the the other guy gave about refuelling on a precarious world, where your players have unknowningly landed on the side of a snow packed mountain. And, even though there was already an avalanche to get rid of the dangerous loose snow from under your ship, there's also a massive ice sheet covering a ravine that's cracking under the weight of your 100 ton type-S.

OR, one of your players hacks away with either a pick ax or an ice saw, only to have the sheet tiles towards a valley hidden by a snow bank. Time for a saving throw

OR, maybe you aren't the only things breathing on this world...

 

[Shonner]

Hey Shonner, I meant to reply to you, but got sidetracked with the whole Neptune thing.

I like the example you and the the other guy gave about refuelling on a precarious world, where your players have unknowningly landed on the side of a snow packed mountain. And, even though there was already an avalanche to get rid of the dangerous loose snow from under your ship, there's also a massive ice sheet covering a ravine that's cracking under the weight of your 100 ton type-S.

OR, one of your players hacks away with either a pick ax or an ice saw, only to have the sheet tiles towards a valley hidden by a snow bank. Time for a saving throw

OR, maybe you aren't the only things breathing on this world...

Something like The Thing (1951). Or Planet of the Apes (1968). The ship is angled so that its hot reactors are melting the snow and the ship starts to sink through the ice sheet and down she goes. The ship was responding to an alien distress call. That ship is encased in the ice, for who knows how long.

 

[Carlobrand]

Something like The Thing (1951). Or Planet of the Apes (1968). The ship is angled so that its hot reactors are melting the snow and the ship starts to sink through the ice sheet and down she goes. The ship was responding to an alien distress call. That ship is encased in the ice, for who knows how long.

There was a Niven story where the pilot inadvertently ignites the ices on Pluto. Apparently there was an oxygen layer amidst the various other ices. I suspect an actual player would cry foul and start quoting chemistry at me, Trav players tending to be pretty knowledgeable, but it still made for a good story.

 

[Blue Ghost]

Something like The Thing (1951). Or Planet of the Apes (1968). The ship is angled so that its hot reactors are melting the snow and the ship starts to sink through the ice sheet and down she goes. The ship was responding to an alien distress call. That ship is encased in the ice, for who knows how long.

Imagine having to go through a "Thing" episode while refuelling via shovel on Io. Just you, maybe a few friends, and some shovels. Oof o:

 

[Shonner]

Imagine having to go through a "Thing" episode while refuelling via shovel on Io. Just you, maybe a few friends, and some shovels. Oof o:

I haven't seen The Europa Project (heard it was lame), but I can imagine a Traveller one-shot doing a similar plot.

 

[Carlobrand]

Imagine having to go through a "Thing" episode while refuelling via shovel on Io. Just you, maybe a few friends, and some shovels. Oof o:

Yea, right: a mutable vacuum-capable "Thing" with it's own ... personal ... oxygen ... supply ... ...

HOLY @#%&!

 

[Blue Ghost]