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#21
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"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/p...an_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 -- 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 |
#22
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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. |
#23
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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? 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. Jan -- Sander +++ Out of cheese error +++ |
#24
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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/p...an_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 * |
#25
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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 | |
#26
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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. |
#27
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"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 * |
#28
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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 |
#29
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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 |
#30
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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 |
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