The food-problem

Hello Ekkehard

I dont think what you are suggesting is feasible as the spheres formed were minute, think about how a drop of mercury would go when dropped in gravity from height on to a flat surface. The fluid did not mix properly with the soil so I think they used a hydrated gel as a growing medium.

The more I think about this the more I think that spinning a spacecraft to produce artificial gravity makes sense. Even 0.1G would make a lot of things easier.

I think the first step would be much more enhanced recycling systems onboard space stations/crafts. Currently the supply needed on a space station is about 15-30 kilograms per day and crew member. So it would make sense to first invest massively in advanced recycling systems (where the Russians lead the field).

For larger "colonies" I guess the only usable way is nano-engineering. That means making your food (and other supplies) out of single atoms. IBM achieved this step already in the laboratory. They did make small molecules out of single atoms like in the kit system. Of course, we are still far away before we can use such technology. But as it's technologically possible (and that is proved) it's the "easiest" way on the long-term as you only need energy and some mass (atoms) which can be fully recycled.

About growing plants in Zero-G. The Russians made experiments from their first space stations on. They had big difficulties to get them grow and still have problems with cultivating them. Often the plants grow and flower but won't seed. I guess that will be a major research field for the Russians on the ISS besides their also long history of materials processing.

This article in SpaceRef talks about a "rapid-growth aeroponic system" for growing plants in 0g. Plants are suspended in air and are sprayed with water containing nutrients. The article quotes a water saving of 98%.


http://www.spaceref.com/news/viewpr.html?pid=22478

I downloaded a few pdf's about the hydropnics and aeroponics and it's fairly simple to do (on earth). Hydroponics would be a little bit difficult, but if you have a hydropnics system with low pressure so the water with the nutrient solution in it is constantly pumped around. Aeroponics is indeed simpler and indeed, the water savings are huge since you spray the nutrient-water solution directly onto the root systems. Besides, i've read that NASA allready has a system working with this. They apparently had it all, plants to clean the sewage and a condens-system to get drinking water from the air.

Plus, for comparison, they would need a surface area of 8 square meters of algae for 1 man for an equilibrium in the oxygen/carbondioxide cyclus. stack these up with a few cm of space between them, you can have a lot of these on 1 square meter.

Instead of shooting up those silly science experiments which they don't even intend to use in the near future, shoot up an agriculture and try to get at least the oxygen/carbondioxide cyclus done with plants and/or algae.

Plus, if you would these leds: http://www.ledtronics.com/ds/plantled/ you would save a hell of a lot of energy by using these instead of the normal lightbulbs.

Plus, if you can grow crops which don't need a lot of space, you can also stack the aeroponics system.

I wouldn't imagine that light bulbs would be a problem.

All you would need would be a shiny reflector that collected sunlight itself, and shone it into a pod through a few glass filters that would filter out any unwanted light.

Actually any window is a big problem for a space craft. That is why there are so few of them. More likely they will have solar panels to power lights. They need power anyway, and a bigger solar panel is cheaper than a window in space.

Is glass or plexiglass that fragile?

On a sidenote. The oxygen and carbon dioxide cycle is complete, but if you wanted to keep the air airlike with 7x% nitrogen, is the nitrogen being used by humans or plants? So, in what sense could you replenish the nitrogen if its being used?

My understanding is that the problems with windows have to do with heat transfer. Here is a quote from the source: http://science.nasa.gov/headlines/y2001/ast21mar_1.htm
Thermal management in space craft is a big deal, and one that is never mentioned by people saying they can design cheap space craft.

Thermal management of spacecraft is critical, but it's well understood, can be modelled, and there are practical solutions.

One very interesting possibility to solve or adress the food-problem might be a finding an article under www,wissenschaft.de has published today.

The article says that five years ago a robot found black melanine.rich mushrooms growing on the walls inside the destroyed nuclear reactor in Czernobyl.

Scientists investigated and analysed the finding and experimented. They found that the mushrooms use and apply the melanine to trnasform the radiation into energy to use it fro their growth. This is likened to the photosynthesis done by plants.

For their study the scientists exposed some mushrooms to radiation of 500 times the natural background radiation.

As one consequence the scientists have the idea that such mushrooms might be an abundant source of food for astronauts during long-term space missions - because of the high amount of radiation in space.

The article refers to Arturo Casadevall (Yeshiva-Universität, New York) et al.: PLoS ONE, DOI: 10.1371/journal.pone.0000457 ( www.plosone.org/doi/pone.0000457 ).



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

May be that the term "mushrooms" was quite wrong here - the finding has been published under www.space.com in between where the term "fungus" is used instead. The article reporting about it is "Fungi Thrive on Dangerous Radiation" ( www.space.com/scienceastronomy/070529_f ... ation.html ):






Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Such as?

Any good articles on this?

Regarding the fungi - what about testing this by an enhancement of MSL?

The experiment could be if the fungi grow using the level of space radiation on the martian surface. They could be kept within the MSL bat without protection against the radiation. It might be possible also to add some martian soil to find out how they react to it.

May be that MSL can't be outfitted to do so no more but what about a particular mission for such experiments then? It could be a preparation for a manned Mars mission.

May be that the martian soil would have to be modified previously - might be tested using a sample returned but that sample might be too small.

What about it?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Quick and dirty back of the envelope calculation indicates that assuming photosynthesys if 1% efficient you need about 20m*2 to provide enough food for an adult human if you use algae under ideal conditions. Algae can be "digested" and recombined to create syntetic food, probably won't win any food quality prizes but it'll keep you alive. I favour abandong photosynthesys altogether. I have a life support cycle chart around here somewhere and on it the byproduct of CO2 scrubber recycling is CH4. I am sure there is a bug somewhere that turns CH4 into carbohydrates to be used in food synthesys.

The best measured photosynthetic efficiency for "Chlorella" Algae was 39%! (Probably with monochromatic light) At this rate a single human needs only a 2 ft by 2 ft ( 0.37 square meter) "Farm", collecting sunlight 24 hours a day.

The Chlorella was in a water solution and of course will absorb all the Human metabolic CO2 and uses other metabolic waste products. Zero g actually reduces the problem of keeping the algae well mixed and suspended in the solution within its clear plastic pipes.

Use this as a planning baseline. If you approach within an order of magnitude of this efficiency, you still need only 4 square meters of "Solar Window" - a square two meters on a side.

Chlorella is a good nutrient and can be substituted for wheat, "Corn" or rice as a flour. None of these staples is particularly attractive as a food by itself. (Plan on breeding chickens (fed on algae) wherever you are.)

I bought Chlorella starter material from "Carolina Biological" and have been able to grow the Algae in one drop of that suspension thousandfold in a few ounces (80cc) of solution. I have not, however, achieved either rapid growth or a high algae density.

On the other hand, I am not in any way skilled as a botanist!