why outer space?

Al life forms have a mechanism called the active sodium pump in the
cell walls. It is the primary method of removing excess salt from
inside the cell. What you would want to do is create a membrane with
this mechanism, and possibly run it using electricity. The pump is
actually very efficient using one electron 1.2 eV to transport a
single ion of sodium from one side of the membrane to the other,
without any pressure difference.

Bill

> Also, it is not impossible that new techniques will significantly
drop the
> cost of "seawater mining". Until the invention of the reverse
osmosis
> process, for example, the only way to desalinize seawater was
distillation,
> much more expensive... I even have a wacky intuition that maybe
genetic
> engineering can be of some help here. Theoretically, you could
design
> bacteria able to produce specially designed enzymes that could
catalyze the
> formation of crystals of some specific mineral. (E.g., here are
bacteria
> able to build magnetite crystals inside themselves.) Of course it
would be
> very difficult to find the right molecular shapes (protein folding
is a
> hellish problem) and I have no idea if that would be economically
viable; it