On 6 Dec 2014 at 21:51, Bill Rutherford wrote:

> My players are, in desperation, en route to an icy rock to try to
> obtain fuel.  The ship has fuel scoops and a refiner but it just sank
> in to me (but apparently has not to them, yet...) that scoops are for
> skimming.  Somehow I don't imagine a fuel scoop being something like
> a wood chipper where you feed stuff in one end and out comes sawdust
> - er, water...
>
> It would seem plausible that the players would set up a pre-fab
> shelter of some sort, sealed to the (frozen) ground, and would
> essentially mine water within it, feeding the fuel refiner via hose
> or the like.
>
> OK - how full of holes is this, and how should it *really* (in the
> context of the game) be done?

Well, given that it's fairly standard to refuekl from rivers, lakes
and oceans, handling *liquid* isn't going to be too much trouble.
Probably some fitting on the fuel refiner that you hook a hose to.

The hard part is going to be getting the chunks of ice and melting
them.

You can't just "seal" something to the surface. It's probably rough,
and unless it's "minor planet" sized, the gravity is essentially
non-existents.

You should be able to "stake" something down to keep chunks from
flying away as you break them off. But breaking them off is going to
be a problem. Swinging a pick in zero-gee is not teribly practical.

With lucky, the surface is more like snow. So you can "shovel" it.

But once you have the "snow" or "ice chunks" into a container, you
get the *real* fun.

Unless the body is a fair sized asteroid or moonlet, it won't be
differentiated. So the ice will be fairly "dirty, and be a mix of
waterm annonia and methane (and possibly more complex organics).

Note that the three melt at very different temps, and turn to gas at
still different temps. Water will still be solid when the methane is
a gas, The ammonia would be as well, except that it will tend to
react with the water giving mixes with various different melting &
boiling points.

Me, I'd try shoveling it into a section of hold that can be sealed
fairly well. Once it's mostly full, seal it up with a hose at the
bottom. Then start raising the temp. Pump out the liquid (and gases
as they come off the ices.

But there's going to be a lost of "dust" mixed in with the ice
(that's why comets are described as dirty iceballs). That'll become
mud. Which can clog things up (and being fairly fine grained, it's
apt to cause a lot of wear and tear on the pumping mechanism).

As I recall, one of Ringo & Taylors "Looking Glass" books has them
attempting to get water from an icy body in deep space. With
predictable problems.

Ah, found it. Chapter 11 of Manxome Foe. Go find a copy somewhere and
read thru.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com