Running multiple HET in parallel?

"Allen Thomson" :

Ian Stirling wrote:


The claim is basically rubbish.

No, freeze-dried stuff may not have all of the nutrients it once did
ten years out, or be quite as tasty.

I checked on MREs and the Army's nutrition lab says that they're
nutritionally good beyond 10 years if held unfrozen at 15 C
(60 degrees 'murkin). So I agree, the claim that a few-year
mission couldn't get along on preserved food plus some
supplements looks pretty odd.

If you can haul it, of course, but it isn't clear where the
mass of a closed or semi-closed system becomes significantly
less than that of a fridge full of high-tech TV dinner
equivalents. And there are issues of reliability, power,
contamination associated with a veggie garden in space, let
alone an escargot ranch.

See, another problem. Escargot? When you could be growing shrimp, crabs and
lobsters? What a waste.

Earl Colby Pottinger

--
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John Schilling wrote:
"Allen Thomson" writes:

Ian Stirling wrote:

The claim is basically rubbish.

No, freeze-dried stuff may not have all of the nutrients it once did
ten years out, or be quite as tasty.

I checked on MREs and the Army's nutrition lab says that they're
nutritionally good beyond 10 years if held unfrozen at 15 C
(60 degrees 'murkin). So I agree, the claim that a few-year
mission couldn't get along on preserved food plus some
supplements looks pretty odd.

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

And how many tens of millions of people would get better nutrition eating
only MREs?

For a mars trip, if an orbiter is part of the scheme, it's not horribly
difficult to keep a freezer at 100K for the duration.

Dehydrated food stored at 100K, some frozen luxuries, and multivitamins.
Get some chefs in to compete and produce dishes that taste nice, or
at least not too horrible.
(100K is arbitrary, I could not quickly find any reference to food
nutritional values stored at low temps for long periods)

John Schilling wrote:
"Allen Thomson" writes:


I checked on MREs and the Army's nutrition lab says that they're
nutritionally good beyond 10 years if held unfrozen at 15 C
(60 degrees 'murkin). So I agree, the claim that a few-year
mission couldn't get along on preserved food plus some
supplements looks pretty odd.


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.

Er, I used the MREs as an example of the preservability of food
while retaining whatever nutritional virtue it started out
with. In the case of MREs, that virtue seems to be considerable,
if not long-term adequate.

However, the viewgraph that started this seemed to say that
the state of the art isn't here for preserving nutritionally
adequate food for multi-year Mars missions. So is there some
ingredient of a multi-year nutritionally complete diet that
can't be preserved by chilling or freezing or dehydration or
whatever? If so, what might it be?

Derek Lyons wrote:
Earl Colby Pottinger wrote:
To me it sounds like some at NASA is fishing for more money instead of
storing dehydrated at low temperatures.

Right. And the only evidence introduced to date that NASA is wrong is
the marketing hyperbole of survivalist websites.

Well, it's not all getting posted, but I spent a while looking into this
when I first did the One Way to Mars mission architecture back in 1996.

I have the actual DOD MRE lifetime specs somewhere. Below 60F,
they can be made to last arbitrarily long. Long before you get
to liquid nitrogen, MRE and equivalently well packed other
storable food will last longer than a human lifetime. Merely
keeping them within 5 degrees of freezing is plenty.

The specifics of why the DOD recommends you not eat MREs and only
MREs for several years have to do with the design of the MRE itself
not inherent to long term usage of stored food. The MRE is intended
to be a combat ration and to be blunt, grossly overnourishes troops
if they're eating the recommended quantity per day. US troops are
going into the field and getting fat *in combat* eating MREs these
days, a phenomenon previously unheard of in wartime logistics of
any era. Their specs for field food prep and environmental condition
survival are also extreme as are their ability to be produced by the
tens of millions of units.

People could theoretically survive adequately on beef jerky and
vitamin pills for some years. Though I am not volunteering to
be the guinea pig for that one, I think it illustrates the
magnitude of how well solved this problem is.

There is also a huge difference between needing to be able to
grow or have fresh supplies of *everything*, and having a few
fresh items which are supplements to a storable base diet.
For example, a few strawberries greatly liven up a breakfast
or lunch which otherwise is essentially infinitely storable.
Or a fresh tomato. Very small addons which are known to
be amenable to hydroponics and zero-G cultivation will
give taste and texture boosts and largely overcome stored
food monotony.

I did joke in my presentation at Case for Mars IV that one
of the reasons to leave the Lifetime expedition crew there
was that if they came back, they might track me down and
strangle me for having send them out there with stored
food for all that time. But all joking aside, this is
not nearly the problem that it's being made out to be.
I have never known an ECLSS nutritionist in the last
ten years who didn't believe that storable was an
entirely practical option. I have also never met an
astronaut or astronaut candidate who would seriously
reject going on a Mars mission just because the meals
for six years were going to be MRE quality.

I am wondering if we're seeing a partial repeat of the
Bush(41) NASA "all roads to doing anything on Mars
must pass through my personal fiefdom" problem.
The specifics of the claim on the roadmap presentation
defy extensive research and the community consensus
within the ECLSS community as far as I have been
able to ascertain, and this point directly bears
on the validity of One Way missions so I have been
asking around and researching it.

In my specifically fairly educated opinion, the statements
on pp 21 of the human studies powerpoint are not
well founded and should not be taken as accurate.
If the authors of that document would like to
back it up with some additional research which
contradicts the institutional assumptions which
have been in place for at least the last 10 years
then they should feel free to, but baldly asserting
that it's true is not reasonable.


-george william herbert

John Schilling wrote:
"Allen Thomson" writes:
Ian Stirling wrote:
The claim is basically rubbish.
No, freeze-dried stuff may not have all of the nutrients it once did
ten years out, or be quite as tasty.

I checked on MREs and the Army's nutrition lab says that they're
nutritionally good beyond 10 years if held unfrozen at 15 C
(60 degrees 'murkin). So I agree, the claim that a few-year
mission couldn't get along on preserved food plus some
supplements looks pretty odd.

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.

The MRE particulars are the proof by demonstration, not the
actual final implimentation. Final implimentation will almost
certainly make use of a lot more well frozen food and stuff
that you just can't reasonably do for field MRE use and field
MRE volume requirements. Deep frozen meat and some veggies are
obvious, deep frozen fruit in some cases easy in some not,
and for some types of fruits and veggies it looks like they
just don't store well and won't be on the menu.

I wonder how well sushi does in LN2...


-george william herbert

Allen Thomson wrote:
However, the viewgraph that started this seemed to say that
the state of the art isn't here for preserving nutritionally
adequate food for multi-year Mars missions. So is there some
ingredient of a multi-year nutritionally complete diet that
can't be preserved by chilling or freezing or dehydration or
whatever? If so, what might it be?

I second this question, as my decade of research before and
after the One Way to Mars lifetime mission proposal says
that the space nutrition community consensus is an
overwhelming "storage is fine" and directly contradicts
that slide.


-george william herbert

(Derek Lyons) :

Earl Colby Pottinger wrote:

To me it sounds like some at NASA is fishing for more money instead of
storing dehydrated at low temperatures.

Right. And the only evidence introduced to date that NASA is wrong is
the marketing hyperbole of survivalist websites.

And the little fact that as they rotate thier stock, eating the old stuff yet
are not dying of Malnutrition says otherwise.

The dehydrated foods that are the same foods used by campers and mountain
climbers for weeks, sometimes months at a time while doing serious work. If
the food was lacking in nutrition it would show up relative early at thier
work levels.

Now if the food is stored at 100K or lower why do you think the food is going
to lose any nutritional value?

Earl Colby pottinger
--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

Michael Smith wrote:
On Wed, 23 Feb 2005 01:09:42 +0000 (UTC)
Sander Vesik wrote:

Dried fish and meat keeps for years, especially so in cold weather.
Now as for not getting scurvy, you need a way to make vitamin C stay
around.

Concentrated vitamin C tablets are readily available now. I would expect
that you could get away with a source of carbohydrate and protein,
combined with food additives in tablet form.

Yes, but they have limited keeping times - certainly limited to that
of dried fish and meat, though.. I don't exct that to be problem wither.

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?

--
Sander

+++ Out of cheese error +++

Ian Stirling wrote:

Dehydrated food stored at 100K, some frozen luxuries, and multivitamins.
Get some chefs in to compete and produce dishes that taste nice, or
at least not too horrible.
(100K is arbitrary, I could not quickly find any reference to food
nutritional values stored at low temps for long periods)

Well, we know at the very least that mammoth stored in permafrost for
thousands of years was edible and didn't cause any undesirable side
effects. Unfortunately there were no nutrionists in existence back then.
Given that AFAIK there is at least one un-melted carcass in teh hands of
Russian Academy of sciences, finding out what happens to meat nutitionaly
over such long period of time might not be impossible.

--
Sander

+++ Out of cheese error +++

"Paul F. Dietz" wrote in message
...
Michael Smith wrote:

Correct me if I am wrong, but I can't see anybody supporting the
development of nuclear rocket engines, given the political problems
associated with simple RTGs.

Why should this follow? RTGs are much more radioactive at launch
than are reactors.

Because those who oppose RTGs most loudly aren't exactly dealing with
rational arguments to begin with.


The bigger problem with space reactors is development cost and
lack of application.

Paul