Running multiple HET in parallel? [Archive]

Henry Spencer

February 14th 05, 05:18 AM

In article . com>,
Allen Thomson > wrote:
>It would be interesting to know if there is currently
>any propulsion approach available that would allow
>significantly faster than Hohmann trips for humans
>to other planets/moons/major asteroids... "Currently available"
>can be interpreted to mean "available by 2025 at a development
>+ procurement cost of no more than $10G in 2004 dollars
>per year between now and then."

Yes: orbital assembly/fueling will let you do faster-than-Hohmann trips
for small expeditions with chemical propulsion. You need an orbital fuel
depot, and lots of fuel launches, but the former is fairly straightforward
if you don't insist on using LH2, and the latter provides high flight
rates for RLVs and a large competitive market for launchers of all sorts.

Double yes: if you're willing to spend a bunch on R&D to reduce launch
rates -- which is probably a bad deal, but is undeniably attractive to
organizations that specialize in R&D -- solid-core nuclear rockets can
considerably improve the picture, speeding things up further or permitting
larger expeditions or both. Rover/NERVA solved most of the major
technical problems of a first-cut version in the 60s, and demonstrated
that a fast-paced program could improve the state of the art remarkably
quickly in this area. You can start with NERVA derivatives, and pursue
more ambitious designs in parallel with the first expeditions. The one
big hassle is low-emissions test facilities, and it's one that should
yield quickly to substantial amounts of money -- no breakthroughs are
required.

Liquid-core or nuclear-lightbulb is substantially better, and gas-core
is much better, although they are longer-term options with significant
development issues.

>Equally intresting would be to know about the technology
>for life support systems that would reasonably reliably
>sustain a half-dozen people for two or more years in
>space without help from Earth.

Adequate water recycling -- the big issue -- has been demonstrated, on
a modest scale. (Air is a minor side issue by comparison.) The simplest
way to address the food loop is not to try, given that freeze-dried food
weighs less than half a ton per man-year. Generally, much the simplest
and most reliable way to tackle a lot of the smaller recycling/repair
issues is brute force: more mass, and more fuel to push it, is cheaper
than major engineering R&D.

Of course, trying to sell that approach to R&D-oriented organizations is a
bit of a challenge. "Anything which they do not wish to do is always
lacking in technology. Whether single stage to orbit or Mars missions,
the technology is never quite ready..." (Jim French)

--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

D Schneider

February 14th 05, 05:23 AM

Allen Thomson > wrote:

[...]
> Equally intresting would be to know about the technology
> for life support systems that would reasonably reliably
> sustain a half-dozen people for two or more years in
> space without help from Earth.
>

Which leads me down the path to wondering about life support in large
"cycler hotels"; it is easy to imagine that such a venue would have more
repair resources than a small station (ISS, for example). More tools, a
machine shop (wonder what a 0g machine shop would look like!), spare
parts, etc.

But on the flip side, it isn't clear yet that all the ELCS could be scaled
up for a larger venue; would you need to have 15 Elektron units for a 50
person hotel? Or could you do it with 2 or 3 units (enough overcapacity
that if one unit is offline, the other could cover for a reasonable repair
period)?

/dps

--
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Richard Hofer

February 14th 05, 02:57 PM

In recent years, Hall thruster clusters (i.e., running in parallel)
have been investigated by the Air Force and the University of Michigan.
As a first stab, there have been no show stoppers identified with
operating Hall thrusters together. Brian Beal's Ph.D. dissertation was
concerned with a cluster of four 200 W thrusters and Mitch Walker also
devoted portions of his dissertation on a pair of 5kW thrusters. You
can find both of these at:
http://www.engin.umich.edu/dept/aero/spacelab/publications/dissertations.html

For a while now, the Air Force has been focussed on clusters as a means
to achieve high-power operation, while NASA has continued with
monolithic thrusters. This was for a variety of reasons, not the least
of which is that NASA is looking at using Hall thrusters at several
hundred kilowatts, while the Air Force will probably stay below 100 kW
for quite a while. As NASA continues to push to higher powers, there
will be a logical point where Hall thruster clusters become necessary.
This is for a variety of reasons, not the least of which are thrust
density, limitations on the magnetic circuits, vacuum facility
limitations, and redundancy. One concept for using Hall thrusters in
the Moon/Mars initiative is to attach them to cargo tugs that go back
and forth from LEO to some higher orbit, or even all the way to the
destination. The crew shows up much later after making a "quick" trip
on a chemical rocket. These types of missions require, at least,
several hundred kilowatts.

Michael Smith

February 15th 05, 11:01 AM

On Mon, 14 Feb 2005 05:18:28 GMT
(Henry Spencer) wrote:

> You can start with NERVA derivatives, and pursue
> more ambitious designs in parallel with the first expeditions. The
> one big hassle is low-emissions test facilities, and it's one that
> should yield quickly to substantial amounts of money -- no
> breakthroughs are required.
>
> Liquid-core or nuclear-lightbulb is substantially better, and gas-core
> is much better, although they are longer-term options with significant
> development issues.

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.

A nuclear-electric thruster system, while inefficent, can at least be
built from well understood components.

I know the USSR had spacecraft with reactors. Did the USA use them early
on as well?
--
Michael Smith
Network Applications
www.netapps.com.au | +61 (0) 416 062 898
Web Hosting | Internet Services

Paul F. Dietz

February 16th 05, 01:13 PM

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.

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

Paul

Ian Stirling

February 16th 05, 01:16 PM

Michael Smith > wrote:
> On Mon, 14 Feb 2005 05:18:28 GMT
> (Henry Spencer) wrote:
>
>> You can start with NERVA derivatives, and pursue
>> more ambitious designs in parallel with the first expeditions. The
>> one big hassle is low-emissions test facilities, and it's one that
>> should yield quickly to substantial amounts of money -- no
>> breakthroughs are required.
>>
>> Liquid-core or nuclear-lightbulb is substantially better, and gas-core
>> is much better, although they are longer-term options with significant
>> development issues.
>
> 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.

Well, I support it.

John Schilling

February 17th 05, 08:15 AM

Michael Smith > writes:

>On Mon, 14 Feb 2005 05:18:28 GMT
(Henry Spencer) wrote:

>> You can start with NERVA derivatives, and pursue
>> more ambitious designs in parallel with the first expeditions. The
>> one big hassle is low-emissions test facilities, and it's one that
>> should yield quickly to substantial amounts of money -- no
>> breakthroughs are required.

>> Liquid-core or nuclear-lightbulb is substantially better, and gas-core
>> is much better, although they are longer-term options with significant
>> development issues.

>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.

>A nuclear-electric thruster system, while inefficent, can at least be
>built from well understood components.

I'm not following your logic. The "political problems associated with
simple RTGs", were entirely due to A: some minor but non-negligible
safety issues pertaining *only* to RTGs and not to any other space
nuclear power system, and B: the fact that they used the N word.

"Nuclear rocket" and "nuclear electric thruster system", both use
the N word. If the political problems associated with simple RTGs
will suffice to kill the one, they will just as surely suffice to
kill the other.

In fact, the political problems associated with simple RTGs, were
overcome, and the RTGs flew. With that trail now blazed, I don't
think nuclear systems are unthinkable. But if they are, they are
*all* unthinkable.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

Allen Thomson

February 18th 05, 02:10 AM

Speaking of such matters, see

http://www.spaceref.com/news/viewsr.html?pid=15443

In particular see the Power Point (sorry) presentation

"Session 6: Human Mars Exploration Mission Architectures and
Technologies"

Malcolm Street

February 18th 05, 09:04 AM

Paul F. Dietz 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.
>
Indeed, a point that's often overlooked.

RTGs start at peak radioactivity and then decay.

A reactor can be launched inert, with sod-all radioactivity, and then sent
critical when in a safe orbit (I recall c. 1000 miles being a figure
mentioned in a debate on this here quite a while ago).

> The bigger problem with space reactors is development cost and
> lack of application.
>
Yes. For electicity generation, compared to RTGs a reactor is much more
complicated, much more expensive to develop and probably much heavier and
bulkier.

There just hasn't been anything that's needed the sort of high long-term
power a reactor can put out. A manned mission to Mars, though...

Nuclear rockets (I include the type of HET array being suggested in this
definition) are another matter. So far there hasn't been anything that
hasn't been able to be done with chemical rockets. However (again) a
manned mission to Mars could well be such a mission; the problems of bone
loss and radiation exposure could prove to be such that a nuclear rocket
would be the only way to get there in a time that would keep the crew in
condition to actually do something when they got there, let alone back on
Earth. You'd have the weight of shielding to consider, and it could be a
trade-off between radiation from the engine and radiation from space. (ie
light shielding may allow sufficiently faster acceleration and hence
shorter journey times that you actually reduce overall radiation exposure).

I'm a great fan of Stephen Baxter, but his novel "Voyage" really doesn't do
the NERVA nuclear-thermal rocket program justice; it was both saner and
more successful than he makes out. For a start, in theory at least with
the hydrogen fuel radioactive emissions were limited to the 2% or so of
hydrogen that was deuterium. Of course the problem was that bits of engine
got spat out the back as well, but it was acceptable by '60's standards.
Of course you'd have to be more careful now.

--
Malcolm Street
Canberra, Australia
The nation's capital

Ian Stirling

February 20th 05, 10:42 AM

Malcolm Street > wrote:
> Paul F. Dietz 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.
>>
> Indeed, a point that's often overlooked.
>
> RTGs start at peak radioactivity and then decay.

Almost true.
But, the decay chain may make more radioactivity come out of the device
as time goes on, and the output switches to hard to shield stuff.

Allen Thomson

February 20th 05, 04:01 PM

Henry Spencer wrote:

> The simplest way to address the food loop is not to try,
> given that freeze-dried food weighs less than half a ton
> per man-year. Generally, much the simplest and most
> reliable way to tackle a lot of the smaller recycling/
> repair issues is brute force: more mass, and more fuel
> to push it, is cheaper than major engineering R&D.

> Of course, trying to sell that approach to R&D-oriented
> organizations is a bit of a challenge. "Anything which
> they do not wish to do is always lacking in technology.
> Whether single stage to orbit or Mars missions,
> the technology is never quite ready..." (Jim French)

I don't know enough about long-term nutrition and related
matters to have an opinion, but note that the manned-Mars
presentation at the recent Mars roadmap meeting contains
the following assertions at slide 21:

http://www.hq.nasa.gov/office/apio/ppt/mars/human_studies.ppt

Closing the life-support air and water loops with low
expendables is a key leveraging technology for long
duration human exploration missions

Current food preservation technology is not capable of
providing nutritionally viable food for the longer
mission durations under study. Food production
technologies under the environmental conditions of these
missions is not developed to the point of being the
primary source of food.

Power requirements for both closed loop life support and
food production can be significant, indicating that
advanced life support and advanced power systems are
closely coupled.

[Boxed summary]

Closing the air and water loops is essential to reduce the
total mass of long duration missions to a reasonable level.

Improvements in food storage technology or production
technology are also needed to reduce overall mass and ensure
crew health.

Sander Vesik

February 20th 05, 07:32 PM

John Schilling > wrote:
>
> In fact, the political problems associated with simple RTGs, were
> overcome, and the RTGs flew. With that trail now blazed, I don't
> think nuclear systems are unthinkable. But if they are, they are
> *all* unthinkable.
>

RTG-s being thinkable in some scenarios does not in and of itself
make other nuclear systems so. These will have to do their own
trailblazing, the more complex and the closer to Earth they have to
operate, the more so.

--
Sander

+++ Out of cheese error +++

Jan Vorbrüggen

February 22nd 05, 07:54 AM

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

I wonder...didn't some of the early Artic and Antarctic expeditions
go several years without resupply?

Jan

Paul F. Dietz

February 22nd 05, 01:11 PM

Jan Vorbrüggen wrote:

> I wonder...didn't some of the early Artic and Antarctic expeditions
> go several years without resupply?

Does shooting seals count as resupply?

Paul

Earl Colby Pottinger

February 22nd 05, 03:54 PM

"Allen Thomson" > :

> I don't know enough about long-term nutrition and related
> matters to have an opinion, but note that the manned-Mars
> presentation at the recent Mars roadmap meeting contains
> the following assertions at slide 21:
>
> http://www.hq.nasa.gov/office/apio/ppt/mars/human_studies.ppt
>
> Closing the life-support air and water loops with low
> expendables is a key leveraging technology for long
> duration human exploration missions
>
> Current food preservation technology is not capable of
> providing nutritionally viable food for the longer
> mission durations under study. Food production
> technologies under the environmental conditions of these
> missions is not developed to the point of being the
> primary source of food.

This reads like an out and out lie to me. Water storage is basicly forever.
But all the end-of-the-world nuts and people who just want long term safety
incase of a major national problem have been buying freeze-dried, canned,
sealed and stored in extra cold freezer food that is rated for 5-7-even 10
years storage. And that is just goe average calling a local dealer.

A quick google search using 'long term food storage' gives me for example:
http://waltonfeed.com/self/deh-veg.html

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

Earl Colby Pottinger

--
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Ian Stirling

February 22nd 05, 05:12 PM

Jan Vorbr?ggen > wrote:
>> Current food preservation technology is not capable of
>> providing nutritionally viable food for the longer
>> mission durations under study.
>
> I wonder...didn't some of the early Artic and Antarctic expeditions
> go several years without resupply?

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.
However, add a couple of Kg/year of supplements, and you can live on
practically anything that has enough calories.

No, it may not taste as nice 20 years down the line.

And that's without talking about cryogenic freezing of foods, which may
be almost trivial in some cases, where you've got lots of vacuum and shadow,
the sky is 3K.

If food can take -20C for 6 months, then at -200C, it's going to last for
over a century.

Sander Vesik

February 23rd 05, 01:09 AM

John Schilling

February 23rd 05, 06:20 AM

Earl Colby Pottinger > writes:

>"Allen Thomson" > :

>> I don't know enough about long-term nutrition and related
>> matters to have an opinion, but note that the manned-Mars
>> presentation at the recent Mars roadmap meeting contains
>> the following assertions at slide 21:

>> http://www.hq.nasa.gov/office/apio/ppt/mars/human_studies.ppt

>> Closing the life-support air and water loops with low
>> expendables is a key leveraging technology for long
>> duration human exploration missions

>> Current food preservation technology is not capable of
>> providing nutritionally viable food for the longer
>> mission durations under study. Food production
>> technologies under the environmental conditions of these
>> missions is not developed to the point of being the
>> primary source of food.

>This reads like an out and out lie to me. Water storage is basicly forever.
>But all the end-of-the-world nuts and people who just want long term safety
>incase of a major national problem have been buying freeze-dried, canned,
>sealed and stored in extra cold freezer food that is rated for 5-7-even 10
>years storage. And that is just goe average calling a local dealer.

"Rated", by people who have nothing to lose by making the rating on account
of there won't be any courts left in which to sue them if the scenario in
which their product's performance will ever be tested, actually occurs.

More generally, the people who actually eat five-year-old stored food are
not the ones who have kept scientifically vigorous records of the storage
conditions and then conduct detailed analysis of the present nutritional
balance of the food and the performance of the people exclusively eating
that food. And the people who do study the issue with that degree of
rigor, generally have a funding cycle of less than five years.

NASA is right in that there is very little in the way of food with a
*proven* shelf life of five years, and what there is (MREs, lifeboat
rations, and the like) is known to be not healthy if eaten exclusively
for years on end.

This is not to say that it would be terribly hard to do the tests and
find a suitable assortment of off-the-shelf items for the job. NASA
would almost certainly overdo it, but it *does* take more than just
stocking up on Walton's and Mountain House and whatnot and hoping you
don't find out the hard way that the universe has a surprise in store
for you.

Having the first crew of astronauts to reach Mars, slowly die from
malnutrition, on live television, on the return trip, would be Really
Bad for A: the astronauts, B: NASA or whomever else is running the
mission, and C: the future of human spaceflight in general. It's
going to take us more than five years to build the ships; we can
afford to take five years to properly test the provisions.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

Henry Spencer

February 23rd 05, 02:11 PM

In article >,
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.

As others have noted, cryogenic refrigeration is going to thoroughly halt
any deterioration in stored food, vitamins, etc.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Allen Thomson

February 23rd 05, 09:40 PM

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.

John Schilling

February 24th 05, 07:41 AM

"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.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

Derek Lyons

February 24th 05, 08:25 AM

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.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Michael Smith

February 24th 05, 09:51 AM

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.
--
Michael Smith
Network Applications
www.netapps.com.au | +61 (0) 416 062 898
Web Hosting | Internet Services

Michael Smith

February 24th 05, 10:06 AM

On Fri, 18 Feb 2005 20:04:20 +1100
Malcolm Street > wrote:

> I'm a great fan of Stephen Baxter, but his novel "Voyage" really
> doesn't do the NERVA nuclear-thermal rocket program justice; it was
> both saner and more successful than he makes out.

So am I. IMHO the books he has written which explore the current or near
future space program have a more realistic idea of what is possible than
just about anything I have read. Yes the bit in Voyage about the Nerva
did somewhat put me off the idea.

| Of course the problem was that bits of engine
| got spat out the back as well, but it was acceptable by '60's
| standards. Of course you'd have to be more careful now.

The real problem is that it is a partly open loop system. No other
nuclear power system routinely exhausts significant quantities of
radioactive material. I agree that a modern system would have to be more
careful but I think this would take the design back to the drawing
board.
--
Michael Smith
Network Applications
www.netapps.com.au | +61 (0) 416 062 898
Web Hosting | Internet Services

Earl Colby Pottinger

February 24th 05, 01:57 PM

"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

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
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Ian Stirling

February 24th 05, 09:53 PM

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)

Allen Thomson

February 24th 05, 11:36 PM

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?

George William Herbert

February 25th 05, 03:35 AM

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

George William Herbert

February 25th 05, 03:44 AM

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

George William Herbert

February 25th 05, 03:46 AM

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

Earl Colby Pottinger

February 25th 05, 04:18 AM

(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

Sander Vesik

February 26th 05, 02:33 PM

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 +++

Sander Vesik

February 26th 05, 02:42 PM

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 +++

Greg D. Moore $Strider$

February 27th 05, 12:37 AM

"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

Fred J. McCall

February 27th 05, 06:38 AM

"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

Allen Thomson

February 28th 05, 04:27 AM

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.

Paul E. Black

February 28th 05, 06:28 PM

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 )

D Schneider

February 28th 05, 06:33 PM

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

--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

Marc 182

March 1st 05, 02:45 AM

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 here:

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

Kent Paul Dolan

March 1st 05, 08:21 AM

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=military+nutrition+research

HTH

xanthian.

Herman Rubin

March 1st 05, 02:49 PM

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

D Schneider

March 2nd 05, 12:29 AM

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=military+nutrition+research

(in Message-ID: . com>)

Tanx, guys!

/dps

--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

Sander Vesik

March 2nd 05, 03:33 AM

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

March 2nd 05, 06:56 PM

D Schneider > wrote:

>> http://www.dscp.dla.mil/subs/subsbo/TDP/tdone.pdf
>> http://www.google.com/search?q=military+nutrition+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

--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

John Schilling

March 6th 05, 07:36 PM

"Allen Thomson" > writes:

>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.

Right. The issue isn't "retaining whatever nutritional virtue
it started out with"; a hermetically sealed container of pure
cane sugar will do that. Lots of foods, we know how to store
more or less indefinitely.

The issue is whether a long-term adequate diet can be constructed
exclusively from storable foods. The answer is probably yes, but
not yet AFIK *proven* to be yes.

>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?

Don't know; I can't find the original references at my local
library or online, just abstracts and summaries. What I can
find suggests it isn't anything as simple as a missing vitamin
or amino acid or whatnot. But in the course of developing the
MRE, the Army did *something* to the mix that resulted in a
food that would last indefinitely if kept cold, but will lead
to unexplained weight loss and mental deterioration if used
exclusively for more than a few weeks.

If it were trivial to produce a ration that could be stored
indefinitely and consumed exclusively, I would assume that
the Army would have done so in developing the MRE. It would
certainly have been a useful enough combination to be worth
a little bit of extra effort.

So I take the MRE, and similar rations, as evidence that it is
not trivial to produce rations suitable for long-term space
flight. I don't expect it to be hugely difficult either; like
the zero-gravity toilet it's just one of those things that has
to be done and will be done but isn't quite as easy as it sounds
like it should be.

At very least, three or four years before the first manned Mars
mission we ought to take our best guess and put it to the test.
Round up a batch of graduate students or other suitable guinea
pigs, give them the locker or freezer full of astro-MREs, and
say "This is all you get to eat for the next three years. Let
us know how it works out..."

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

John Schilling

March 6th 05, 07:41 PM

"Allen Thomson" > writes:

>Michael Smith wrote:

>> It would be interesting to work out how much of a
>> spacecraft you would have with a couple of submarine
>> style fission reactors and as many ion or hall thrusters
>> as you had power for.

>> Given the lack of enthusiasm for this approach I can
>> only assume that it doesn't deliver transit times short
>> enough to be safe for humans.

>It would be interesting to know if there is currently
>any propulsion approach available that would allow
>significantly faster than Hohmann trips for humans
>to other planets/moons/major asteroids. (Our moon
>excepted, of course.) "Currently available" can be
>interpreted to mean "available by 2025 at a development
>+ procurement cost of no more than $10G in 2004 dollars
>per year between now and then."

If by "significantly faster" you mean a factor of two or
so, that can be done.

A minimum-energy transfer to Mars takes somewhere between
240 and 260 days, depending on what launch window you use.
Looking at payload delivery from low Earth orbit to low
Mars orbit using various propulsions systems, we get:

LOX-LH2 Chemical Rocket: 240 days 25% payload fraction
Nuclear Thermal Rocket: 240 days 45% payload fraction
Nuclear Electric Drive: 300 days 45% payload fraction
Solar Electric Drive: 300 days 40% payload fraction

"Nuclear Thermal", means running liquid hydrogen through a
hot reactor core and exhausting the gas through a nozzle -
same principle as a chemical rocket, but different energy
source and lighter working fluid. This has been tested
on the ground, back when open-air nuclear reactors were
an acceptable thing, but never flown.

"Electric Drive" refers to an ion or plasma thruster system
similar to what I described in an earlier post, using either
a nuclear reactor or advanced solar arrays as a power source.
The longer trip time comes from the necessary acceleration
period using low-thrust propulsion, and these are systems
that have flown at a smaller scale and on solar power.

If we're looking for a factor of two improvement in speed,
we can use moderately high energy orbits using any of these
propulsion systems.

LOX-LH2 Chemical Rocket: 120 days 10% payload fraction
Nuclear Thermal Rocket: 120 days 30% payload fraction
Nuclear Electric Drive: 180 days 30% payload fraction
Solar Electric Drive: 180 days 20% payload fraction

So, even if we are stuck using chemical rockets, we can get
four-month trips if we are willing to accept 10:1 mass
ratios. And we can do better than that if we are willing
to go nuclear, using reasonably well established but of
course politically controversial technology. Even if we
have to use fluffy green solar power, we can still beat
chemical rocketry and the Hohmann orbit by a fair margin

If you want weeks instead of months, no go using any
technology we can forsee for the next two decades. And
note that for all of these, launch windows open every
2.15 years. Interplanetary travel without regard for
launch windows is another thing we aren't going to be
doing in this generation, though in the case of Mars
missions you can frequently get an off-year window at
tolerable cost by using a Venus flyby.

>Equally intresting would be to know about the technology
>for life support systems that would reasonably reliably
>sustain a half-dozen people for two or more years in
>space without help from Earth.

For a mission of that scale, you'd keep it simple and use
industrial chemistry to close the air and water loops.
Roughly speaking, the human body turns clean water into
dirty water, water content of food into dirty water, and
dry food plus air into carbon dioxideand clean water with
a little bit of solid waste on the side.

That last step is critical, because it means there is
a surplus of water in the output stage which can be
used directly to make up for inefficiencies in your
water recycling system or electrolyzed to make up for
inefficiencies in your oxygen recycling system.

A physiochemical life support system for a two- to
three-year mission would consist of six major elements:

A vapor distillation unit to turn dirty water into
clean water, with the impurities concentrated in a
brine that is vented overboard (along with a little
bit of water, but as noted we can make that up).

A molecular sieve or other regenerable physiochemical
system for extracting carbon dioxide and other trace
impurities from the cabin atmosphere

A Sabatier reactor for turning carbon dioxide plus
hydrogen into methane plus water. The methane we
might be able to make use of or might just vent,
the water we for sure can make use of.

A water electrolysis unit to turn the surplus water
(both from human respiration and the Sabatier reactor)
into oxygen and hydrogen. The hydrogen feeds back
into the Sabatier reactor, and the oxygen goes into
the cabin air.

An incineration or other oxidation unit to reduce
the solid waste to ash and recover what water and
carbon dioxide we can.

And a stockpile of canned, dehydrated, frozen, or
otherwise preserved food, details yet to be determined.
If it isn't fully dehydrated, that's still more surplus
water that can be used to compensate for inefficiencies
elsewhere.

The hardware would mass about 200-500 kilograms per man
with current technology, and consume about one kilowatt
per man of electric power.

Stored consumables would ammount to about two kilograms
per man per day, mostly food. Minor consumables would
be nitrogen to make up for atmospheric leakage, hydrogen
for the Sabatier reactor (that loop can't be fully closed
without a very large excess of water to electrolyze),
maybe ammonia or hydrazine in place of seperate nitrogen
and hydrogen if the mass balance is right, various personal
and environmental hygene supplies, filters and other parts
for the machinery, and packaging for all of the above.

With a bit of effort and austerity, it might be possible
to get the consumables requirement down to 1 kg/man-day,
but almost certainly no further unless you start growing
your own food. And that's not worth the bother for only
a few people and a few years.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

Henry Spencer

March 7th 05, 10:53 PM

In article >,
Herman Rubin > wrote:
>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.

Except, of course, that's not what anyone is proposing. The only way you
*could* do that would be chemical synthesis of food, which is out of the
question. Realistic proposals all involve preserved normal foods, and the
only significant question is whether absolutely everything of importance
survives preservation.

And as has already been noted, anything that will survive freezing *will*
survive essentially indefinitely in cryogenic refrigeration. So there
should be no difficulty with anything that's needed only in trace amounts,
given a modest amount of frozen whole food as a supplement to dehydrated
stuff.

People have lived on such diets -- in fact, on diets considerably inferior
to that -- for periods of a year or more in places like the polar regions.
Extending this to Mars-mission durations would require some confirming
experiments to be absolutely certain, but major trouble is most unlikely.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Paul F. Dietz

March 8th 05, 02:56 AM

John Schilling wrote:

> If we're looking for a factor of two improvement in speed,
> we can use moderately high energy orbits using any of these
> propulsion systems.
>
> LOX-LH2 Chemical Rocket: 120 days 10% payload fraction
> Nuclear Thermal Rocket: 120 days 30% payload fraction
> Nuclear Electric Drive: 180 days 30% payload fraction
> Solar Electric Drive: 180 days 20% payload fraction

I'll point out that you can start the mission from highly eccentric
earth orbit and reduce the delta-V requirements. You could
send cargo, propellant and supplies up into that orbit, perhaps using
low thrust electric rockets, adding the crew only when you
were ready to launch to Mars.

(If radiation in HEEO is too high you can start in a much higher
orbit and do a small burn to pass again near the Earth, where
you make your main burn to inject to Mars.)

Paul

Carey Sublette

March 9th 05, 01:41 PM

"John Schilling" > wrote in message
...
> "Allen Thomson" > writes:
...
>>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?
>
> Don't know; I can't find the original references at my local
> library or online, just abstracts and summaries. What I can
> find suggests it isn't anything as simple as a missing vitamin
> or amino acid or whatnot. But in the course of developing the
> MRE, the Army did *something* to the mix that resulted in a
> food that would last indefinitely if kept cold, but will lead
> to unexplained weight loss and mental deterioration if used
> exclusively for more than a few weeks.

I think the "cherry box" on the viewgraph:
" Improvements in food storage technology or production technology are also
needed to reduce overall mass and ensure crew health."
states the issue accurate, but the other sentence on the slide:
"Current food preservation technology is not capable of providing
nutritionally viable food for the longer mission durations under study"
is a bit of a misstatement.

Ensuring crew health requires a diet that is varied and palatable so that
the crew eats properly, and the food itself is not a source of stress on the
mission (psychological health).

And the trick is to do it with low mass foods (i.e. dehydrated).

Also, nutrition science is far beyond the RDA stage - finding the essential
individual components in a diet required for health. We all know about the
debates about what makes an *optimum* healthy diets:
What kind of fats and in what proportion?
How much and what kind of fiber?
How much flavonoids and carotenoids, and what kinds, with what ratios?
Etc.

I think it is the combined problem of satisfying all of these together, and
quite clearly no one has ever developed a food system like this before.

The whole viewgraph presentation is about design trade-offs, and the dietary
aspect of a mission is going to involve trade-offs of its own. For a
palatable, optimally healthy, indefinitely storable diet a solution is at
hand right now - just prepare thousands of excellent meals and freeze them
in ready-to-eat form. But this is quite heavy with all that water.
Maintaining the good qualities of those meals but getting rid of the water
mass, not so easy.

Carey Sublette

Herman Rubin

March 10th 05, 08:57 PM

In article >,
Henry Spencer > wrote:
>In article >,
>Herman Rubin > wrote:
>>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.

>Except, of course, that's not what anyone is proposing. The only way you
>*could* do that would be chemical synthesis of food, which is out of the
>question. Realistic proposals all involve preserved normal foods, and the
>only significant question is whether absolutely everything of importance
>survives preservation.

>And as has already been noted, anything that will survive freezing *will*
>survive essentially indefinitely in cryogenic refrigeration. So there
>should be no difficulty with anything that's needed only in trace amounts,
>given a modest amount of frozen whole food as a supplement to dehydrated
>stuff.

You are underestimating the nature of the problem. If a
large enough variety of foods, from enough regions, are
used, this might not be a problem. One nutrient which I
mentioned, selenium, is a problem in both directions; one
needs enough, and not too much, and where food is grown can
make a large difference.

>People have lived on such diets -- in fact, on diets considerably inferior
>to that -- for periods of a year or more in places like the polar regions.
>Extending this to Mars-mission durations would require some confirming
>experiments to be absolutely certain, but major trouble is most unlikely.

The polar regions might not be the worst. The American
Midwest was known as the "goiter belt" because of a
shortage of iodine. In this case, the danger of too much
is not that great, but I do not know what the effect would
be if too much accumulates in recycled water.

There can be some problems which cannot occur on earth;
in these cases, our ignorance is immense. We have no
idea about the need, if any, for aluminum and silicon,
and as soil is mainly composed of aluminum silicates,
a shortage is not a problem. I know an excess of
aluminum can be toxic, and is difficult to test for.

--
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

David Summers

March 11th 05, 11:54 PM

That said, there are people that have survived long periods of time
eating only one type of meal.

Um, personally I spent a year eating only curry rice and oatmeal - and
a different year eating mainly hamburgers... not that I am
particularly healthy, though.

The solution is obviously to send only teenagers - they can survive
eating anything!

-David

John Schilling

March 20th 05, 03:32 AM

"Paul F. Dietz" > writes:

>John Schilling wrote:

>> If we're looking for a factor of two improvement in speed,
>> we can use moderately high energy orbits using any of these
>> propulsion systems.

>> LOX-LH2 Chemical Rocket: 120 days 10% payload fraction
>> Nuclear Thermal Rocket: 120 days 30% payload fraction
>> Nuclear Electric Drive: 180 days 30% payload fraction
>> Solar Electric Drive: 180 days 20% payload fraction

>I'll point out that you can start the mission from highly eccentric
>earth orbit and reduce the delta-V requirements. You could
>send cargo, propellant and supplies up into that orbit, perhaps using
>low thrust electric rockets, adding the crew only when you
>were ready to launch to Mars.

If the mission is payload delivery, you almost certainly can't start
that from a highly eccentric earth orbit, because very few payloads
are going to originate in highly eccentric earth orbit. For that
mater, very few spaceships are going to be built in highly eccentric
earth orbit. You have to count boosting the ship and payload to
the highly eccentric earth orbit as part of the mission.

Which is still quite efficient if you're using a low-thrust propulsion
system, and is part of the assumed mission plan for the SEP and NEP
cases above. Passengers, yes, can join the ship a bit later, but
passengers are only a minor portion of the payload even on a passenger
ship.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

John Schilling

March 20th 05, 04:01 AM

"Carey Sublette" > writes:

>"John Schilling" > wrote in message
...
>> "Allen Thomson" > writes:

>>>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?
>>
>> Don't know; I can't find the original references at my local
>> library or online, just abstracts and summaries. What I can
>> find suggests it isn't anything as simple as a missing vitamin
>> or amino acid or whatnot. But in the course of developing the
>> MRE, the Army did *something* to the mix that resulted in a
>> food that would last indefinitely if kept cold, but will lead
>> to unexplained weight loss and mental deterioration if used
>> exclusively for more than a few weeks.

>I think the "cherry box" on the viewgraph:
>" Improvements in food storage technology or production technology are also
>needed to reduce overall mass and ensure crew health."
>states the issue accurate, but the other sentence on the slide:
> "Current food preservation technology is not capable of providing
>nutritionally viable food for the longer mission durations under study"
>is a bit of a misstatement.

>Ensuring crew health requires a diet that is varied and palatable so that
>the crew eats properly, and the food itself is not a source of stress on the
>mission (psychological health).

>And the trick is to do it with low mass foods (i.e. dehydrated).

>Also, nutrition science is far beyond the RDA stage - finding the essential
>individual components in a diet required for health.

Right, and the failures of known long-term stored-food diets are not at
the RDA, individual-componet level either.

>I think it is the combined problem of satisfying all of these together, and
>quite clearly no one has ever developed a food system like this before.

>The whole viewgraph presentation is about design trade-offs, and the dietary
>aspect of a mission is going to involve trade-offs of its own. For a
>palatable, optimally healthy, indefinitely storable diet a solution is at
>hand right now - just prepare thousands of excellent meals and freeze them
>in ready-to-eat form. But this is quite heavy with all that water.

It's not that easy, alas. Not all foods retain everything that used to
make them nutritious and palatable through a freeze/thaw cycle, at least
using known freezing and thawing processes, and I'm not aware of any
successful attempt at providing a healthy long-term diet using only those
foods known to freeze well.

>Maintaining the good qualities of those meals but getting rid of the water
>mass, not so easy.

Getting rid of most of the water would be a plus, but *all* of the known
preservation methods - freezing, canning, dehydrating, and the rest - have
limits. The early arctic and antarctic expeditions were not seriously
mass-limited, at least for their base camps, and certainly did not lack
for refrigeration. They could and did carry their choice of canned and
frozen food, all fully hydrated, and yet found that a full overwinter
stay was testing the limits of endurance on such a diet.

Again, I don't think this is likely to be a major problem. We know more
about food preservation than we did in the early 20th century, and we
know from their experience what doesn't work and what the problems are.
But we also know more about transport logistics than we did in the early
20th century, and have used that to ensure that we never had to test our
presumed ability to have people live for years without any resupply.

That's something we are going to have to test before we sent people to
Mars with an assortment of canned, frozen, and dehydrated food. Tweaking
the diet to increase the fraction of dehydrated food is a secondary goal.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

Paul F. Dietz

March 20th 05, 01:28 PM

John Schilling wrote:

> If the mission is payload delivery, you almost certainly can't start
> that from a highly eccentric earth orbit, because very few payloads
> are going to originate in highly eccentric earth orbit. For that
> mater, very few spaceships are going to be built in highly eccentric
> earth orbit. You have to count boosting the ship and payload to
> the highly eccentric earth orbit as part of the mission.

However, the ship without payload can be placed into that orbit
slowly, then the payload added near the time of injection to Mars.
This is not possible if that delta-V were instead used to send
the vehicle directly to Mars.

Whether this is significant may depend on just where the concern
about transit time is coming from. For crews, it may come from
concerns about reliability of the systems and/or radiation exposure,
and in that case it would be significant.

The system that boosts payloads into HEEO can also be staged
and left in HEEO, where it is more easily reused. One could
also imagine using schemes such as power beaming from Earth or
other sources in cis-lunar space, which again are also not possible
if the vehicle had been injected directly to Mars from LEO.
Breakdowns during the boost to HEEO are more easily repaired
than if the vehicle is en route to Mars.

Paul

Carey Sublette

March 21st 05, 01:59 PM

"John Schilling" > wrote in message
...
> "Carey Sublette" > writes:
>
>>"John Schilling" > wrote in message
...
>>> "Allen Thomson" > writes:
>
>>>>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?
>>>
>>> Don't know; I can't find the original references at my local
>>> library or online, just abstracts and summaries. What I can
>>> find suggests it isn't anything as simple as a missing vitamin
>>> or amino acid or whatnot. But in the course of developing the
>>> MRE, the Army did *something* to the mix that resulted in a
>>> food that would last indefinitely if kept cold, but will lead
>>> to unexplained weight loss and mental deterioration if used
>>> exclusively for more than a few weeks.
>
>>I think the "cherry box" on the viewgraph:
>>" Improvements in food storage technology or production technology are
>>also
>>needed to reduce overall mass and ensure crew health."
>>states the issue accurate, but the other sentence on the slide:
>> "Current food preservation technology is not capable of providing
>>nutritionally viable food for the longer mission durations under study"
>>is a bit of a misstatement.
>
>>Ensuring crew health requires a diet that is varied and palatable so that
>>the crew eats properly, and the food itself is not a source of stress on
>>the
>>mission (psychological health).
>
>>And the trick is to do it with low mass foods (i.e. dehydrated).
>
>>Also, nutrition science is far beyond the RDA stage - finding the
>>essential
>>individual components in a diet required for health.
>
> Right, and the failures of known long-term stored-food diets are not at
> the RDA, individual-componet level either.
>
>
>>I think it is the combined problem of satisfying all of these together,
>>and
>>quite clearly no one has ever developed a food system like this before.
>
>>The whole viewgraph presentation is about design trade-offs, and the
>>dietary
>>aspect of a mission is going to involve trade-offs of its own. For a
>>palatable, optimally healthy, indefinitely storable diet a solution is at
>>hand right now - just prepare thousands of excellent meals and freeze them
>>in ready-to-eat form. But this is quite heavy with all that water.
>
> It's not that easy, alas. Not all foods retain everything that used to
> make them nutritious and palatable through a freeze/thaw cycle, at least
> using known freezing and thawing processes, and I'm not aware of any
> successful attempt at providing a healthy long-term diet using only those
> foods known to freeze well.

With modern freezing technology there are very few foods that cannot be
frozen effectively. At worst the penalty is loss of texture, not nutrition,
and texture loss can be compensated by food preparation technique (e.g.
tomatoes become mushy when forzen, but any dish that cooks tomatoes loses
the texture anyway).

>>Maintaining the good qualities of those meals but getting rid of the water
>>mass, not so easy.
>
> Getting rid of most of the water would be a plus, but *all* of the known
> preservation methods - freezing, canning, dehydrating, and the rest - have
> limits. The early arctic and antarctic expeditions were not seriously
> mass-limited, at least for their base camps, and certainly did not lack
> for refrigeration.

Ahem - no.

Early arctic and antarctic expeditions did *not* have access to "frozen
food"! Frozen foods, in the sense we are discussing, are not just foods that
happen to be frozen. They are foods that preserved intact by a process of
rapid freezing at very low temperatures, and kept frozen continuously by
maintaing temperatures of below -18 C. This means having the food frozen in
a plant at the peak of edibility, and maintained at very cold temperatures
through active refigeration continuously from that moment on. Early
expeditions to the arctic did not have access to such.

The break-through Birdseye process was developed in the 1920s, and frozen
foods only came available in 1930. Only expeditions substantially later than
this could have had adequate support to supply them with properly frozen
foods.

> They could and did carry their choice of canned and
> frozen food, all fully hydrated, and yet found that a full overwinter
> stay was testing the limits of endurance on such a diet.

What do you mean limits of endurance? If you are talking about palatable
diet, this is the same issue I brought up as the principal real problem.

> Again, I don't think this is likely to be a major problem. We know more
> about food preservation than we did in the early 20th century, and we
> know from their experience what doesn't work and what the problems are.
> But we also know more about transport logistics than we did in the early
> 20th century, and have used that to ensure that we never had to test our
> presumed ability to have people live for years without any resupply.
>
> That's something we are going to have to test before we sent people to
> Mars with an assortment of canned, frozen, and dehydrated food. Tweaking
> the diet to increase the fraction of dehydrated food is a secondary goal.

I think the mass problem of the food supply is a bigger issue (in the minds
of NASA at least) than you are allowing.

D Schneider

March 21st 05, 07:33 PM

John Schilling > wrote:

[...]
> It's not that easy, alas. Not all foods retain everything that used to
> make them nutritious and palatable through a freeze/thaw cycle, at least
> using known freezing and thawing processes, and I'm not aware of any
> successful attempt at providing a healthy long-term diet using only those
> foods known to freeze well.

Vitamins in particular tend to degrade, although some of these can be
stored for a couple years in tablet form. 1-A-Day Brand might not be a
good choice -- the pill might end up too big to swallow ;-)
>
>
>> Maintaining the good qualities of those meals but getting rid of the
>> water mass, not so easy.
>
> Getting rid of most of the water would be a plus, but *all* of the known
> preservation methods - freezing, canning, dehydrating, and the rest -
> have limits.

Didn't Henry point out that you're going to need the water anyway*?
What's the difference between carrying it in the freezer and carrying it
in the tank? The value of dehyrdated foods is in "instant meals" (or
snacks), such as cups of soup or noodles, and in suitpacks for short trips
away from base camp.

*water for reconstitution, of course, and also for making ou for ELCSS
losses.

/dps

--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

Ian Stirling

March 21st 05, 11:31 PM

D Schneider > wrote:
> John Schilling > wrote:
>
> [...]
>> It's not that easy, alas. Not all foods retain everything that used to
>> make them nutritious and palatable through a freeze/thaw cycle, at least
>> using known freezing and thawing processes, and I'm not aware of any
>> successful attempt at providing a healthy long-term diet using only those
>> foods known to freeze well.
<snip>
>> Getting rid of most of the water would be a plus, but *all* of the known
>> preservation methods - freezing, canning, dehydrating, and the rest -
>> have limits.
>
> Didn't Henry point out that you're going to need the water anyway*?
> What's the difference between carrying it in the freezer and carrying it
> in the tank? The value of dehyrdated foods is in "instant meals" (or
> snacks), such as cups of soup or noodles, and in suitpacks for short trips
> away from base camp.
>
> *water for reconstitution, of course, and also for making ou for ELCSS
> losses.

Using relatively easy processes, you can greatly reduce water use.
For example, boiled treated dehumidifier water is quite usable, and that
needs little more than I have in this room. (dehumidifier, UVC lamp. ...)

If you're willing to recycle urine too, which is more tricky to filter and
process, then you're getting pretty close to not actually needing makeup
water, but being able to do fine on water from oxygen burnt with food in the
crew.

There are a number of interesting possible ways to recycle almost
everything pretty cleanly.
Heat excrement/urine/waste food/... to 500C or so in a suitable reaction
vessel under pressure, in presence of water, and you practically get out
after a little while water with assorted ions in, and no larger components.

Derek Lyons

March 22nd 05, 01:43 AM

"Carey Sublette" > wrote:

>With modern freezing technology there are very few
>foods that cannot be frozen effectively.

So long as you define 'effectively' to exclude texture, taste, and
visual appeal.

>At worst the penalty is loss of texture, not nutrition,
>and texture loss can be compensated by food preparation
>technique (e.g. tomatoes become mushy when forzen, but
>any dish that cooks tomatoes loses the texture anyway).

Umm.. No. The problems are far more extensive than that, and only
about half of them can be cured by changing the preparation technique.

Pick up a copy of the Ball Blue Book and/or drop rec.food.preserving
and educate yourself.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

John Schilling

March 22nd 05, 07:38 AM

"D Schneider" > writes:

>John Schilling > wrote:

>> Getting rid of most of the water would be a plus, but *all* of the known
>> preservation methods - freezing, canning, dehydrating, and the rest -
>> have limits.

>Didn't Henry point out that you're going to need the water anyway*?
>What's the difference between carrying it in the freezer and carrying it
>in the tank?

No. The water that you need is the water that is *chemically* incorporated
into food. Absolutely, positively, completely, 100.0% dehydrated food
has a chemical formula of rounghly CnH2nOn, plus traces of other stuff,
and if you divide by n and oxidize the C, which is roughly what human
metabolism does, you get H2O. A little more than a cupful a day, but
that's a cupful that's being added to your otherwise mostly closed system.
If your recycling is good enough, that should be all you need.

Crudely speaking, if you eat fully dehydrated food and drink, say,
eight cups of water a day, you'll ****, sweat, and exhale nine cups of
water a day. All you have to do is not lose more than a cup a day in
the recycler, and you're set.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

Carey Sublette

March 22nd 05, 01:30 PM

"D Schneider" > wrote in message
news:opsnz5yjddemtzlb@d3h1pn11...
...
>> Getting rid of most of the water would be a plus, but *all* of the known
>> preservation methods - freezing, canning, dehydrating, and the rest -
>> have limits.
>
> Didn't Henry point out that you're going to need the water anyway*?
> What's the difference between carrying it in the freezer and carrying it
> in the tank? The value of dehyrdated foods is in "instant meals" (or
> snacks), such as cups of soup or noodles, and in suitpacks for short trips
> away from base camp.
>
> *water for reconstitution, of course, and also for making ou for ELCSS
> losses.

Ah, but the water for reconstitution can be used over and over and over
(reclaimed from waste and air of course).

Some water in frozen food may actually be needed in the course of the
mission to make for losses or for expendible purposes, in which case it can
be subtracted from the food mass budget.

Lets pencil this out. For a long duration mission (1000 days) with a crew of
8, we have 8000 days of food. A diet is typical 75% water or so, food is
principally carbohydrate and protein containing 4 kilocalories per gram, and
at a 2000 kilocalorie a day diet we have 500g solids, and 1500g water per
person per day. Thus the minimum dry food mass is 4000 kg, with 12000 kg of
water needed. This is really not too bad - I can't imagine it a
make-or-break issue for a Mars mission. On the other hand the entire mass of
the mission vehicle would be on the order of 200 tonnes, so the food water
mass is 6% of the total mission mass. You know they will apply a rigorous
mass budgeting discipline to keep the mission mass down, so the food water
mass is one area they will want to attack. (The NASA PowerPoint presentation
mentioned this specifically.)

BTW - regarding the issue of the nutritive value of frozen foods - there are
no nutrients - essential or otherwise - lost during freezing and thawing.
The only property lost in the food is texture for some types of high-water
foods - principally tomatoes, whole egg, and certain soft fruits (and there
are ways of still incorporating all of these effectively in the diet). Its a
bit harder for dehydrated foods though. (I consulted with my resident food
science graduate-professional on this.)

Carey Sublette

Ian Stirling

March 23rd 05, 01:25 AM

Derek Lyons > wrote:
> "Carey Sublette" > wrote:
>
>>With modern freezing technology there are very few
>>foods that cannot be frozen effectively.
>
> So long as you define 'effectively' to exclude texture, taste, and
> visual appeal.

Millions live on frozen meals, chocolate bars, and fizzy drinks.

If the price of going into space is eating slightly boring food, with much
better nutrition than stuff I might pick off the the supermarket shelf, then
I'm willing to make the supreme sacrifice.

I suspect I'm not alone.

Carey Sublette

March 23rd 05, 12:45 PM

"Derek Lyons" > wrote in message
...
> "Carey Sublette" > wrote:
>
>>With modern freezing technology there are very few
>>foods that cannot be frozen effectively.
>
> So long as you define 'effectively' to exclude texture, taste, and
> visual appeal.
>
>>At worst the penalty is loss of texture, not nutrition,
>>and texture loss can be compensated by food preparation
>>technique (e.g. tomatoes become mushy when forzen, but
>>any dish that cooks tomatoes loses the texture anyway).
>
> Umm.. No. The problems are far more extensive than that, and only
> about half of them can be cured by changing the preparation technique.
>
> Pick up a copy of the Ball Blue Book and/or drop rec.food.preserving
> and educate yourself.

Umm... are you aware of the differences between state-of-the-art flash
freezing technology and home canning?

Evidently not.

Educate yourself.

Carey Sublette

Carey Sublette

March 24th 05, 04:14 AM

"Ian Stirling" > wrote in message
...
>D Schneider > wrote:
>> John Schilling > wrote:
>>
>> [...]
>>> It's not that easy, alas. Not all foods retain everything that used to
>>> make them nutritious and palatable through a freeze/thaw cycle, at least
>>> using known freezing and thawing processes, and I'm not aware of any
>>> successful attempt at providing a healthy long-term diet using only
>>> those
>>> foods known to freeze well.
> <snip>
>>> Getting rid of most of the water would be a plus, but *all* of the known
>>> preservation methods - freezing, canning, dehydrating, and the rest -
>>> have limits.
>>
>> Didn't Henry point out that you're going to need the water anyway*?
>> What's the difference between carrying it in the freezer and carrying it
>> in the tank? The value of dehyrdated foods is in "instant meals" (or
>> snacks), such as cups of soup or noodles, and in suitpacks for short
>> trips
>> away from base camp.
>>
>> *water for reconstitution, of course, and also for making ou for ELCSS
>> losses.
>
> Using relatively easy processes, you can greatly reduce water use.
> For example, boiled treated dehumidifier water is quite usable, and that
> needs little more than I have in this room. (dehumidifier, UVC lamp. ...)
>
> If you're willing to recycle urine too, which is more tricky to filter and
> process, then you're getting pretty close to not actually needing makeup
> water, but being able to do fine on water from oxygen burnt with food in
> the
> crew.

The requirements for water purification a Mars mission are not too
demanding.

The average production rate is on the order of 1/2 liter per hour, with a
total system lifetime production of 10,000 liters. Further the cost of
operating the system can be quite high - $1000/liter would not be problem
for this application. The reclamation/recycling system must be light and not
need much maintenance though.

As a thought experiment, consider water purification by electrolyzing the
water to hydrogen and oxygen, then burning it back to water. This would
satisfy any need for purity I should think. The energy cost for operating
this system would be on the order of 1500 watts, not a problem for a vehicle
of this magnitude.

> There are a number of interesting possible ways to recycle almost
> everything pretty cleanly.
> Heat excrement/urine/waste food/... to 500C or so in a suitable reaction
> vessel under pressure, in presence of water, and you practically get out
> after a little while water with assorted ions in, and no larger
> components.

The solid matter in the waste would be much more difficult to put to use,
and also is much lighter than the water so probably just retaining it in
tanks for shielding would be the best use.

Carey Sublette

Carey Sublette

March 24th 05, 01:44 PM

"Ian Stirling" > wrote in message
...
> Derek Lyons > wrote:
>> "Carey Sublette" > wrote:
>>
>>>With modern freezing technology there are very few
>>>foods that cannot be frozen effectively.
>>
>> So long as you define 'effectively' to exclude texture, taste, and
>> visual appeal.
>
> Millions live on frozen meals, chocolate bars, and fizzy drinks.
>
> If the price of going into space is eating slightly boring food, with much
> better nutrition than stuff I might pick off the the supermarket shelf,
> then
> I'm willing to make the supreme sacrifice.
>
> I suspect I'm not alone.

And it need not be even slightly boring!

There is a very substantial, and growing, frozen gourmet food industry. A
little googling, or a trip to a high-end supermarket, easily turns up an
vast range of products.

Stae-of-the-art commercial super flash freezing (which uses ammonia baths
at -65 C), vacuum sealed pouches, and well-controlled preparation processes
introduces few compromises in texture, taste, or appearance and none in
nutrition. Frozen foods are often better in nutrition and not infrequently
in esthetic qualities compared to "real world" fresh, because shipping,
handling, and storage allow for more deterioration for the "fresh".

Sander Vesik

March 25th 05, 09:04 PM

Ian Stirling > wrote:
> Derek Lyons > wrote:
> > "Carey Sublette" > wrote:
> >
> >>With modern freezing technology there are very few
> >>foods that cannot be frozen effectively.
> >
> > So long as you define 'effectively' to exclude texture, taste, and
> > visual appeal.
>
> Millions live on frozen meals, chocolate bars, and fizzy drinks.

Yeah, and if it goes badly, part of that is "school meal" ...

>
> If the price of going into space is eating slightly boring food, with much
> better nutrition than stuff I might pick off the the supermarket shelf, then
> I'm willing to make the supreme sacrifice.
>
> I suspect I'm not alone.

I think somewhere the priorities of space programs etc have gone terribly
awry. Why is it that nothing can happen unless teh astronauts are in way
less danger than sailors on common 1st world fishing boats? Never mind
3rd world ones.

Couldn't we just assign them a certain amount of weight and size into which
they can fit their food and then have them make their own decisions? They
are adult, after all...

--
Sander

+++ Out of cheese error +++

D Schneider

March 28th 05, 08:05 PM

Sander Vesik > wrote:

[...]
> I think somewhere the priorities of space programs etc have gone terribly
> awry. Why is it that nothing can happen unless teh astronauts are in way
> less danger than sailors on common 1st world fishing boats? Never mind
> 3rd world ones.
>
> Couldn't we just assign them a certain amount of weight and size into
> which
> they can fit their food and then have them make their own decisions? They
> are adult, after all...
>

But they aren't acting on their own. They are being *sent* by *us*. On
*our* dime. When this changes, then *we* don't have to be responsible for
their safety.

/dps

--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

Paul F. Dietz

April 3rd 05, 02:00 AM

D Schneider wrote:

> But they aren't acting on their own. They are being *sent* by *us*.
> On *our* dime. When this changes, then *we* don't have to be
> responsible for their safety.

Why do we have to be responsible for their safety anyway? Is some
big nanny in the sky going to shake her finger at us?

Paul

Derek Lyons

April 5th 05, 05:11 PM

"Carey Sublette" > wrote:
>There is a very substantial, and growing, frozen gourmet food industry. A
>little googling, or a trip to a high-end supermarket, easily turns up an
>vast range of products.

It turns up what seems to be a vast range. In reality, you find it's
a fairly narrow range with a bunch of different producers for each
article. Most of the foods in question are 'gourmet' only because
their labels say so. Their target audience is those that want to
think that by eating 'gourmet' foods they are a 'gourmet'. Madison
Avenue determined years ago that the motto of most consumers is 'style
over substance'.

>Stae-of-the-art commercial super flash freezing (which uses ammonia baths
>at -65 C), vacuum sealed pouches, and well-controlled preparation processes
>introduces few compromises in texture, taste, or appearance and none in
>nutrition.

That's the theory anyhow. The reality is otherwise. (Type of storage
(frost free vs non-frost free), and defrosting mechanisms play are
large role as well.)

>Frozen foods are often better in nutrition and not infrequently
>in esthetic qualities compared to "real world" fresh, because shipping,
>handling, and storage allow for more deterioration for the "fresh".

If it's deteriorated, it's not fresh Carey.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Snidely.too@gmail.com

April 6th 05, 03:51 AM

Paul F. Dietz wrote:
> D Schneider wrote:
>
> > But they aren't acting on their own. They are being *sent* by
*us*.
> > On *our* dime. When this changes, then *we* don't have to be
> > responsible for their safety.
>
> Why do we have to be responsible for their safety anyway? Is some
> big nanny in the sky going to shake her finger at us?
>
> Paul

As their employer and outfitter, we have that responsibility.
Is that clear enough?

When the time comes that explorers of Mars can be self-employed, fine,
but until then...

/dps

Paul F. Dietz

April 7th 05, 12:48 AM

wrote:

>>>On *our* dime. When this changes, then *we* don't have to be
>>>responsible for their safety.
>>
>>Why do we have to be responsible for their safety anyway? Is some
>>big nanny in the sky going to shake her finger at us?
>
>
> As their employer and outfitter, we have that responsibility.
> Is that clear enough?

It's an argument by assertion. Clear, but completely unconvincing.

Paul

Carey Sublette

April 7th 05, 04:45 AM

"Derek Lyons" > wrote in message
...
> "Carey Sublette" > wrote:
>>There is a very substantial, and growing, frozen gourmet food industry. A
>>little googling, or a trip to a high-end supermarket, easily turns up an
>>vast range of products.
>
> It turns up what seems to be a vast range. In reality, you find it's
> a fairly narrow range with a bunch of different producers for each
> article.
> Most of the foods in question are 'gourmet' only because
> their labels say so. Their target audience is those that want to
> think that by eating 'gourmet' foods they are a 'gourmet'. Madison
> Avenue determined years ago that the motto of most consumers is 'style
> over substance'.

You haven't actually tried the "high-end supermarket" shopping bit have you?

>>Stae-of-the-art commercial super flash freezing (which uses ammonia baths
>>at -65 C), vacuum sealed pouches, and well-controlled preparation
>>processes
>>introduces few compromises in texture, taste, or appearance and none in
>>nutrition.
>
> That's the theory anyhow. The reality is otherwise. (Type of storage
> (frost free vs non-frost free), and defrosting mechanisms play are
> large role as well.)

Uh-huh. And poorly cooked food tastes lousy. Still that says nothing at all
about food that is prepared well.

The point is modern freezing technology works very well. The fact that it
can be stored badly, and defrosted using poor techniques says nothing at
all.

>
>>Frozen foods are often better in nutrition and not infrequently
>>in esthetic qualities compared to "real world" fresh, because shipping,
>>handling, and storage allow for more deterioration for the "fresh".
>
> If it's deteriorated, it's not fresh Carey.

Derek, this is very amusing.

You believe food does not begin deteriorating from the moment it is
harvested (picked/slaughtered) or prepared?

Refrigeration (and other storage techniques, like CO2 atmospheres) retards
deterioration, keeping it to acceptable levels for reasonable periods of
time. Every bit of "fresh" food you buy has deteriorated in measurable ways
from its point of origin. Even if food science isn't your bag (and I'd say,
it isn't), basic biology and chemistry should clue you in on this.

Carey Sublette

April 7th 05, 05:09 AM

> wrote in message
ups.com...
> Paul F. Dietz wrote:
>> D Schneider wrote:
>>
>> > But they aren't acting on their own. They are being *sent* by
> *us*.
>> > On *our* dime. When this changes, then *we* don't have to be
>> > responsible for their safety.
>>
>> Why do we have to be responsible for their safety anyway? Is some
>> big nanny in the sky going to shake her finger at us?
>>
>> Paul
>
> As their employer and outfitter, we have that responsibility.
> Is that clear enough?
>
> When the time comes that explorers of Mars can be self-employed, fine,
> but until then...

There is a more hard-headed answer: the astronaut has agreed to serve as an
agent of exploration for the space program and some billions of dollars are
being invested per astronaut to carry out the exploration mission. The space
program will do everything possible to ensure that the astronaut will remain
capable of carrying out his/her duties to protect the mission (and
investment), and the astronaut will be *required* to comply with a dietary
program that space program nutritionists and psychologists believe will
ensure their continued ability to perform their duties.

There is nothing altruistic about this at all. Ayn Rand would approve.

Carey Sublette

April 7th 05, 02:09 PM

Craig Fink

April 8th 05, 02:15 AM

On Wed, 09 Mar 2005 13:41:12 +0000, Carey Sublette wrote:

> I think the "cherry box" on the viewgraph: " Improvements in food
> storage technology or production technology are also needed to reduce
> overall mass and ensure crew health." states the issue accurate, but the
> other sentence on the slide:
> "Current food preservation technology is not capable of providing
> nutritionally viable food for the longer mission durations under study"
> is a bit of a misstatement.
>
> Ensuring crew health requires a diet that is varied and palatable so
> that the crew eats properly, and the food itself is not a source of
> stress on the mission (psychological health).
>
> And the trick is to do it with low mass foods (i.e. dehydrated).
>
> Also, nutrition science is far beyond the RDA stage - finding the
> essential individual components in a diet required for health. We all
> know about the debates about what makes an *optimum* healthy diets: What
> kind of fats and in what proportion? How much and what kind of fiber?
> How much flavonoids and carotenoids, and what kinds, with what ratios?
> Etc.
>
> I think it is the combined problem of satisfying all of these together,
> and quite clearly no one has ever developed a food system like this
> before.
>
> The whole viewgraph presentation is about design trade-offs, and the
> dietary aspect of a mission is going to involve trade-offs of its own.
> For a palatable, optimally healthy, indefinitely storable diet a
> solution is at hand right now - just prepare thousands of excellent
> meals and freeze them in ready-to-eat form. But this is quite heavy with
> all that water. Maintaining the good qualities of those meals but
> getting rid of the water mass, not so easy.
>
>
>

I've always thought a garden is the way to go. Lots of ......

When I went sailing a while back, it was the fresh stuff I missed most.
The crunch of a nice salad, squish of a fresh tomatoes, that type of
thing. The lettuce we had after two or three weeks (with no refrigeration)
was great, even though I had to peel off the outer centimeter or so of
scum.

That and human converstion, but that won't be a problem with the going to
Mars. Or, will it?????????

--
Craig Fink
Cbhegrfl R-Znvy Jrypbzr @

John Schilling

April 8th 05, 07:51 PM

In article et>, Carey
Sublette says...

> wrote in message
ups.com...

[Arbitrary food selection for astronauts]

>> As their employer and outfitter, we have that responsibility.
>> Is that clear enough?

>> When the time comes that explorers of Mars can be self-employed, fine,
>> but until then...

>There is a more hard-headed answer: the astronaut has agreed to serve as an
>agent of exploration for the space program and some billions of dollars are
>being invested per astronaut to carry out the exploration mission. The space
>program will do everything possible to ensure that the astronaut will remain
>capable of carrying out his/her duties to protect the mission (and
>investment), and the astronaut will be *required* to comply with a dietary
>program that space program nutritionists and psychologists believe will
>ensure their continued ability to perform their duties.

That way, when it turns out that they are unable to perform their duties,
we can say, "See, it's *their fault*, because they *didn't follow the
requirements*", and absolve ourselves of blame.

This is indeed quite important to a lot of people, but some of us are more
interested in whether or not the astronauts can actually perform their duties.
In which case the relevant issue is what they *actually* do, not what they are
*required* to do.

Which are two different things, even for highly motivated people who agree to
the requirements.

You seem to be missing the point here. We know how to freeze or dehydrate
carbohydrates, proteins, fats, vitamins, and minerals sufficient to provide
a nutricious diet. But, food which is not eaten, provides no nutrition, no
matter what its chemical composition. Food which is eaten but not digested,
provides no nutrition, no matter what its chemical composition.

And there is empirical evidence that, even for highly motivated people who
agree to the conditions, the sorts of food most amenable to long-term
storage are the sorts of food least likely to be actually eaten, least
likely to be properly digested if they are eaten, exlusively over a period
of years. To the point of actual malnutrition or undernutrition of people
amply supplied with nutritious food.

There is *also* empirical evidence that, even for highly motivated people
who agree to the conditions, food which was chosen for them by others is
less likely to be eaten and properly digested than food which they chose
for themselves. Again, to the point of actual malnutrition or undernutrition
of people amply supplied with nutritious food.

The first is an intrinsic problem with long-duration spaceflight. Almost
certainly a problem that can be solved with relatively little effort, but
it makes things *harder* if we force the second problem into the proposed
solution of the first.

Fortunately, the nutritionists and psychologists already know this, and if
you ask them in general terms how best to deal with the issue will suggest
leaving most of the decisions to the people who are actually going to be
eating the stuff (or not). Unfortunately, there is a human instinct against
sharing power, so if not knowing any better you outright instruct the
nutritionists and psychologists to specify the diets of the astronauts, they
may not bother to correct you.

--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

snidely

April 8th 05, 07:58 PM

> > As their employer and outfitter, we have that responsibility.
> > Is that clear enough?
>
>
> It's an argument by assertion. Clear, but completely unconvincing.

So you aren't convinced that your empoyer is responsible for providing
a safe stairway in the mutlit-story building he has you work in?

/dps

Carey Sublette

April 9th 05, 03:33 PM

"Craig Fink" > wrote in message
...
> On Wed, 09 Mar 2005 13:41:12 +0000, Carey Sublette wrote:
>
>
>
>> I think the "cherry box" on the viewgraph: " Improvements in food
>> storage technology or production technology are also needed to reduce
>> overall mass and ensure crew health." states the issue accurate, but the
>> other sentence on the slide:
>> "Current food preservation technology is not capable of providing
>> nutritionally viable food for the longer mission durations under study"
>> is a bit of a misstatement.
>>
>> Ensuring crew health requires a diet that is varied and palatable so
>> that the crew eats properly, and the food itself is not a source of
>> stress on the mission (psychological health).
>>
>> And the trick is to do it with low mass foods (i.e. dehydrated).
>>
>> Also, nutrition science is far beyond the RDA stage - finding the
>> essential individual components in a diet required for health. We all
>> know about the debates about what makes an *optimum* healthy diets: What
>> kind of fats and in what proportion? How much and what kind of fiber?
>> How much flavonoids and carotenoids, and what kinds, with what ratios?
>> Etc.
>>
>> I think it is the combined problem of satisfying all of these together,
>> and quite clearly no one has ever developed a food system like this
>> before.
>>
>> The whole viewgraph presentation is about design trade-offs, and the
>> dietary aspect of a mission is going to involve trade-offs of its own.
>> For a palatable, optimally healthy, indefinitely storable diet a
>> solution is at hand right now - just prepare thousands of excellent
>> meals and freeze them in ready-to-eat form. But this is quite heavy with
>> all that water. Maintaining the good qualities of those meals but
>> getting rid of the water mass, not so easy.
>>
>>
>>
>
> I've always thought a garden is the way to go. Lots of ......
>
> When I went sailing a while back, it was the fresh stuff I missed most.
> The crunch of a nice salad, squish of a fresh tomatoes, that type of
> thing. The lettuce we had after two or three weeks (with no refrigeration)
> was great, even though I had to peel off the outer centimeter or so of
> scum.
>
> That and human converstion, but that won't be a problem with the going to
> Mars. Or, will it?????????

This is the one area where no food preservation technology exists: fresh
salads of tomatoes and leafy vegetables.

These are all high water content plants that don't dehydrate, and don't
freeze - doing anything at all to them beyond keeping them fresh turns them
into mush. Some of these ingredients are still good in mush form (think
tomato sauce and sauerkraut) but they aren't fresh (and lettuce fails
utterly - though I do have a book with a New Zealand recipe for baked
lettuce!). You can freeze salads of some of the more carbohydrate rich,
lower water vegetables - but they aren't what most people think of as
"salad".

It might be worthwhile to have a hydroponic unit on a Mars misson to produce
fresh leafy vaegetables and tomatoes for an occasional delicacy, it could
also provide a "garden spot" for the crew.

Carey Sublette

Derek Lyons

April 12th 05, 05:53 AM

"Carey Sublette" > wrote:

>You haven't actually tried the "high-end supermarket" shopping bit have you?

Yes, I have. And you'll find the frozen 'gourmet' foods in them are
largely targeted at a slightly different audience than the fresh
products in the same store. You see the same differentiation even at
a low- or mid- end supermarket.

(Just two weeks ago I was in a high end grocery/restaurant supply
store. Their frozen section was barely as big as that at my local
7-11, and was mostly devoted to ice cream and frozen yogurt. A
telling point.)

>The point is modern freezing technology works very well. The fact that it
>can be stored badly, and defrosted using poor techniques says nothing at
>all.

Ah. The operation was a success, but the patient died.

The point is, modern freezing technology isn't magical. There are
severe compromises in texture and quality. (Especially in mass
production.)

>>>Frozen foods are often better in nutrition and not infrequently
>>>in esthetic qualities compared to "real world" fresh, because shipping,
>>>handling, and storage allow for more deterioration for the "fresh".
>>
>> If it's deteriorated, it's not fresh Carey.
>
>Derek, this is very amusing.
>
>You believe food does not begin deteriorating from the moment it is
>harvested (picked/slaughtered) or prepared?

Did I say that? No.

But the normal degradation of product in shipping and handling isn't
considered 'deterioration'. Deterioration means damage or
putrefecation to the cook.

>Refrigeration (and other storage techniques, like CO2 atmospheres) retards
>deterioration, keeping it to acceptable levels for reasonable periods of
>time. Every bit of "fresh" food you buy has deteriorated in measurable ways
>from its point of origin. Even if food science isn't your bag (and I'd say,
>it isn't), basic biology and chemistry should clue you in on this.

I do know food science. But I don't confuse food scientists with
cooks. Food science is to cooking like a pulp mill is to fine
woodowrking.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Derek Lyons

April 12th 05, 06:03 AM

"Carey Sublette" > wrote:

>
>"Derek Lyons" > wrote in message
...
>> "Carey Sublette" > wrote:
>>>There is a very substantial, and growing, frozen gourmet food industry. A
>>>little googling, or a trip to a high-end supermarket, easily turns up an
>>>vast range of products.
>>
>> It turns up what seems to be a vast range. In reality, you find it's
>> a fairly narrow range with a bunch of different producers for each
>> article.
>
>Check out:
>http://www.hvk.org/hvk/articles/0403/235.html
>
>This is a New York Times account of the frozen foods available from just one
>company for one particular (small) segment of the frozen food market -
>ethnic Indian cuisine in the U.S..

Oddly enough, the article focuses most of it's attention on the snack
foods.

>The frozen foods available for this one market segment runs at least into the
>hundreds of products (go to nice store in an Indian community in the U.S. to check
>it out).

It's like the Asian, Hispanic, etc.. markets I've been in, the
situation is just like that down at my local Safeway; the range of
products is actually fairly narrow. The sheer bulk looks impressive
until you realize there are 12 different manufacturers of Lasagna, 14
different for Salisbury Steaks, etc.

>Similar articles can easily be run about other ethnic markets - Latino/Hispanic,
>Chinese and other East Asian (actually several separate markets), etc.; as well
>as other vegetarian foods, etc.

And these ethnic market segments aren't narrow? In every single
ethnic market I've ever visited (dozens, including a couple of higher
end Oriental markets), the amount of fresh product outweighs the
frozen by at least 2-1.

>Having someone argue that the available high quality frozen food products is
>a "fairly narrow range" is a bit like encountering someone who asserts that
>the automobile has yet to really seriously challenge the horse and carriage.

No, it's like encountering someone who can see the forest for the
trees.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL