Re: [Traveller_TNE] Re: water in ship designs

Interesting points Tom, makes sense for the most part however, regarding the shuttle tiles, they don't transmit heat very well, sorta like the carbon-carbon material demonstration my dad used to do in chemistry classes... for his demo he'd take a sheet of carbonized cloth (IIRC) and would hold it in  one hand and swipe it a time or two with a blowtorch.  Because, of the way they make the stuff it wouldn't burn, least not at those temps.  Same thing with the shuttle tiles, they are physically quite weak, you can poke holes in them with your finger, they're made of glass fiber with lot of air pockets in them.  They serve only to protect the shuttle from the heat of re-entry.  cite: documentary on Discovery channel about the shuttle, the last one crashed and what was done to fix the problem.

The electronics and body heat likely go along way to keeping the shuttle warm enough.  Although this does bring up an interesting subject... space is a vaccumm, the "perfect" insulator...the movie on the Apollo 13 mission indicate that after they'd turned off most of their electronic equipment that it got fairly cold in there.  My question would be how cold?  Did they require heaters prior to the accident or was the heat from all the electronic equipment enough?  How does that relate to Mir, Space Lab, and the ISS?

Regards,
Tim

Tom <> wrote:

--- In , <joel@m...> wrote:
>
> Water - a good shield for Radiation?
>
Water is not really a good "portable" rad shield material.  The
shielding really has to have enough atoms to block the radiation
particles/waves in order to work.  A swimming pool reactor (which is
not use for electrical generation) uses a pool of water 20-30 feet
in diameter 8-12 feet deep.  The reactor pile is at the bottom. 
That is a really thick amount of material to put in a spaceship.
RAD shielding can be made thinner by using high-density materials
such as lead or gold.  A solid shield needs similar mass as the
water but takes up far less volume.  When we get to TL 10+ and start
using crystaliron or superdense materials, the shielding gets even
thinner. 
>
> Could we have double-hulls on spaceships and circulate water
> around 'tween the hulls? If we're near a star, it could act
> as a solar water heater.
>
Yes - although it would be tanks and plumbing rather than just open
space between the inner and outer shell. In direct solar radiation
(AKA Sunlight) the whole ship will heat up.  It is more likely that
the water would be used to cool the sun exposed side of the ship and
to distribute the heat evenly throughout the ship. The sun side will
+ 300ºC and the shade side will be -267ºC.  A heat distribution
system should be included as a standard part of the life support
systems.  (The US space shuttle uses orientation for some amount of
heat control - face the black tiles into the sun and the shuttle
heats up - face the white tiles into the sun and the shuttle cools
down.  (Those NASA guys are clever that way.)
>
> Could we build some sort of temperature diff. engine by taking
> the warm water and the cold water?
>
These kind of thermal exchange systems are really not efficient
enough to run a ship.  But in an emergency it might run your life-
support systems.
>
> Could future astronauts be equipped with gills and the ship be
flooded?
>
T20 added Dolphins as an uplifted race.  They also added an aquatic
race.  Neither of these races use liquid filled ships.  Water and
Electrical circuts just do not mix very well.
>
> -Joel
>

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