Running multiple HET in parallel?

"Allen Thomson" wrote:

: Current food preservation technology is not capable of
: providing nutritionally viable food for the longer
: mission durations under study.

What are they looking at for mission lengths? MREs stored at 60
degrees are good for over ten years.

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

Fred J. McCall wrote:

"Allen Thomson" wrote:

: Current food preservation technology is not capable of
: providing nutritionally viable food for the longer
: mission durations under study.

What are they looking at for mission lengths? MREs
stored at 60 degrees are good for over ten years.

The duration is a tiny bit vague, but a canonical Mars
mission lasts about three years. Extended-stay ones
might go up to five. Really long ones would go beyond
that, but I don't know that any such are being
contemplated in the next few decades.

The question seems not to be so much how long some food
can be preserved, but how long food for a nutritionally
complete diet that can be eaten for years can be preserved.

MREs, being designed to keep troops going in the field for
several weeks, don't meet that requirement (too many calories,
fat, sodium, low in fiber, etc.). They're good for what they
were designed to do, but they weren't designed for long-term
nutrition on a space mission.

What I find puzzling is that the quoted assertion seems to
be saying that neither MRE technology nor other techniques
could preserve a complete diet for several years. For all
I know that might be true, but it would be interesting to
know why.

On Sat, 26 Feb 2005 14:33:33 +0000, Sander Vesik wrote:

Michael Smith wrote:
But of course, in realty, most humans eat un unbalanced and unhealthy (in
way too many ways) diet. Only a small minority manage to develop serious
problems over the timeline of a couple of years. More importantly,
simulation studies are quite easy to carry out down here on Earth.

Its a classical case of way over-complicating and way over-engineering
something just because of "space". Why should the astronauts eat way more
healily up there than down here?

Since there are many things we WON'T know about, it is not absurd to
be very careful about the things we DO.

As an extreme example, are we absolutely sure that several years out
of Earth's magnetic field will not have a deleterious effect? Maybe
eating really healthily might be a cushion against some of those
unknowns.

-paul-
--
Paul E. Black )

George William Herbert wrote:

John Schilling wrote:
[...]
The Army's nutrition lab also says that MREs, new or old, are
nutritionally *bad* if they are the entirety of one's diet for
more than a few weeks. If you believe the Army, you can't just
stock your Mars ship with a three-year supply of MREs and imagine
the problem has been solved.

This is a function of the particulars of the MRE food loadout,
not of "equivalent to MRE technology stored food systems in general".

MRE is a useful simplification of what one would really want to
do, but in reality it wouldn't be anything exactly like a whole
bunch of pallets of DOD standard MRE units.

MREs are probably on a different optimization curve than would be
appropriate for a long-term mission. Nutritionally, I would guess, the
goal was probably sustaining maximum energy: e.g., starches and fats,
with some protein. Other factors in the optimatization were likely to be
ease of preparation as well as storage holding up under a variety of heat
and humidity conditions.

A long-term mission would optimize for maximum health: more emphasis on
vitamin content, fibre, etc. And storage could be tailored to the food,
rather than the other way around, while more elaborate preparation than
"boil water, inject into packet contents" would be more than acceptable.

Is there a URL for the Amry's nutrition lab, and what design factors
*were* used for MREs?

/dps

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In article opsmw66hr2emtzlb@d3h1pn11, says...
George William Herbert wrote:

John Schilling wrote:
[...]
The Army's nutrition lab also says that MREs, new or old, are
nutritionally *bad* if they are the entirety of one's diet for
more than a few weeks. If you believe the Army, you can't just
stock your Mars ship with a three-year supply of MREs and imagine
the problem has been solved.

This is a function of the particulars of the MRE food loadout,
not of "equivalent to MRE technology stored food systems in general".

MRE is a useful simplification of what one would really want to
do, but in reality it wouldn't be anything exactly like a whole
bunch of pallets of DOD standard MRE units.

MREs are probably on a different optimization curve than would be
appropriate for a long-term mission. Nutritionally, I would guess, the
goal was probably sustaining maximum energy: e.g., starches and fats,
with some protein. Other factors in the optimatization were likely to be
ease of preparation as well as storage holding up under a variety of heat
and humidity conditions.

A long-term mission would optimize for maximum health: more emphasis on
vitamin content, fibre, etc. And storage could be tailored to the food,
rather than the other way around, while more elaborate preparation than
"boil water, inject into packet contents" would be more than acceptable.

Is there a URL for the Amry's nutrition lab, and what design factors
*were* used for MREs?

Read all about it he

http://www.dscp.dla.mil/subs/subsbo/TDP/tdone.pdf

and you can click on any specific meal to get it's specs too. It's
entertaining in a strange way.

I recall a suggestion once, apparently seriously, that we should just
fly fat astronauts and feed them starvation rations timed to have them
return home thin. The weight savings over flying large amounts of food
were substantial. Dieting in zero G and testy hungry astronauts, no risk
factors there!

Marc

D Schneider wrote:
Is there a URL for the Army's nutrition lab,
and what design factors *were* used for MREs?

This web search will get you more pertinent answers than
I have ambition to sift; the issue seems to be widely
documented on the Net:

http://www.google.com/search?q=milit...ition+research

HTH

xanthian.

In article ,
Paul E. Black wrote:
On Sat, 26 Feb 2005 14:33:33 +0000, Sander Vesik wrote:

Michael Smith wrote:
But of course, in realty, most humans eat un unbalanced and unhealthy (in
way too many ways) diet. Only a small minority manage to develop serious
problems over the timeline of a couple of years. More importantly,
simulation studies are quite easy to carry out down here on Earth.

Its a classical case of way over-complicating and way over-engineering
something just because of "space". Why should the astronauts eat way more
healily up there than down here?

Since there are many things we WON'T know about, it is not absurd to
be very careful about the things we DO.

As an extreme example, are we absolutely sure that several years out
of Earth's magnetic field will not have a deleterious effect? Maybe
eating really healthily might be a cushion against some of those
unknowns.

There is another problem, which is much more serious than
it might appear. If we reduce the food supply to those
nutrients about which we know, we may end up missing
something important over moderately long periods.

For example, 60 years ago it was thought that selenium is
only toxic. It is now known to be essential. Another is
the huge variety of antioxidants, and at this time, it
seems that the "way to go" is to make sure that there is
a large variety. This may increase costs quite a bit;
colorful fruits are harder to convert to long-term stable
products without losing the nutrients, which are often the
compounds contributing to the color.
--
This address is for information only. I do not claim that these views
are those of the Statistics Department or of Purdue University.
Herman Rubin, Department of Statistics, Purdue University
Phone: (765)494-6054 FAX: (765)494-0558

Marc 182 wrote:


http://www.dscp.dla.mil/subs/subsbo/TDP/tdone.pdf

and you can click on any specific meal to get it's specs too. It's
entertaining in a strange way.


And Kent Paul Dolan wrote:

[...] the issue seems to be widely
documented on the Net:

http://www.google.com/search?q=milit...ition+research


(in Message-ID: .com)


Tanx, guys!

/dps

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Paul E. Black wrote:

As an extreme example, are we absolutely sure that several years out
of Earth's magnetic field will not have a deleterious effect? Maybe
eating really healthily might be a cushion against some of those
unknowns.

Actually, yes WE DO know that it doesn't have a deleterious effect.
And that is because know that the previous times when Earth's magnetic
field dissapared, it left no discernible difference in fossiles. And that
includes various species of Homo. Similarily, no heath aspects are
evident from living aeras with a 2x difference in earth's magnetic field.

--
Sander

+++ Out of cheese error +++

D Schneider wrote:

http://www.dscp.dla.mil/subs/subsbo/TDP/tdone.pdf
http://www.google.com/search?q=milit...ition+research

Actually, these references seem to be of limited utility. The clever PDF
that brings in URLs to other PDFs doesn't seem to spend much time on
calories or nutritional analysis (does specify min and max salt, though,
as well as inspection report codes), and none at all on *why* this meal
was chosen. The google search output seems most helpful when it points to
the order form for buying the reports of the Military Nutrition research,
but tends to return hits where people either ref those in bibliographies
or in biographies (as in "I was there, and I'm an expert").

/dps

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