Space Garden

Marc 182 wrote:

:In article ,
says...
:
: The hurdle you run into right up front is that fairly trivially you can,
: using technology known since the 1950s, get all the supplies you need
: into about a kilo a day per person.
: Now, you have to work out if you can fit your garden into a smaller mass than
: this, it's not a easy task.
:
:What's life like living on a kilo a day? Baby food out of a tube?

It's wrong in any event. You need that much WATER a day.

--
"Rule Number One for Slayers - Don't die."
-- Buffy, the Vampire Slayer

(Henry Spencer) wrote:

:You'd eat freeze-dried or dehydrated food -- quite like what you'd eat on
:a backpacking trip, perhaps packaged a bit differently -- rehydrated with
:recycled water. Uninspired, but reasonably varied and pleasant, menus.
:Occasionally, as a break from routine, a bit of frozen whole food or a
:vegetable or two grown on board. (It *is* worth growing a few plants,
artly as a diversion and partly to add some variety, although they
:wouldn't be a major component of the diet.)

You can get by quite well on a kilo or so of food a day. Troops in
the field do it all the time and they're burning quite a bit of
energy.

We figure it takes on the order of 6+ pounds a day to keep troops in
the field over the short term. The majority of that weight is water.

:You can accept some small water losses, because human metabolism converts
:food to CO2 and water, so any system which isn't doing food recycling
:shows a water excess. So you don't need to recover water from solid
:wastes, and you don't need full recovery from urine.

In addition to this, if you're using fuel cells for some of your
power, you're producing water there as well. You do have to refuel
those cells, but then the mass you're lifting is doing 'double duty'.

--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney

In article ,
Fred J. McCall wrote:
:You can accept some small water losses, because human metabolism converts
:food to CO2 and water...

In addition to this, if you're using fuel cells for some of your
power, you're producing water there as well. You do have to refuel
those cells, but then the mass you're lifting is doing 'double duty'.

A spacecraft that's up there long enough to be doing water recycling is
*probably* going to be solar-powered; fuel-cell reactants simply weigh too
much. Gemini and Apollo used fuel cells mostly because their basic design
was fixed at a time when solar arrays were still in their infancy. (Note
that Soyuz, designed only a few years later, uses solar power.)
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |