There has been a great deal of talk about these 2nd generation bio fuels especially biodisesl from algae, and I was thinking about how spaceflight could really use them.It seems to me that these algae technologies could be used to provide both nutriution and oxygen for human spaceflight. The algae fuel systems consume CO2, water, and sunlight to produce oxygen and simple sugars, like all plants do. However unlike the plants that we normally eat, they do not require all the various minerials and conditions that are required for more complex lifeforms. They also have growing times on the order of a few days, which is very fast compared to plants. What I have been thinking is that long duration human spacecraft could use a simple pipes on the outside of the spacecraft as a bio reactor. The pipes would be exposed to the sunlight, and will use filters and shutters to filter out radiation that is harmful for the algae. CO2 would be extracted from the crew area, concentrated, and pumped into the bio reactor. The algae would then consume the CO2 and release O2, which would be pumped back into the crew cabin. Of course new food processing techniques would have to be developed to transfer the sugar filled algae into something edible. If you think about it algae, as well as, other simple organisms are ideal for space food production, because unlike the more complex lifeforms that we receive most of our food from they require little in resources, and have very quick growth times. Since they are simple they can also be easily genetically engineered to produce the things we need from sunlight.
There's a big snag though, humans cannot eat more than ~100g/day of algae (or more generally single cell proteine) without getting gout. Somewhere during our evolution we lost the ability to break down uric acid, which is a product of DNA / RNA digestion and when we get too much of it, it forms the painful crystals responsible for gout. Spirulina is an excellent food supplement, but not suitable as the main component of your diet. Plus you don't want to be eating nothing but algae soup every day.Fish on the other hand do have the ability to break down uric acid, and Tilapia thrive on a Spirulina diet, so the combination would be very useful for human consumption.
You'd think it wouldn't be that hard to remove the uric acid component, though.
Do not know how you extract CO2 from air.Activated carbon and recycle the activated carbon?Other than chemical processes [such as making methane for example]not sure how you get this impurity out of the air- 1000 ppm is .1 % and might might want to tried to get down to level of 1000 ppm.One could mix the water with the air- use cold and pressurized water- maybe? A problem is no gravity.Edit: I think growing some thing like lettuce and tomatoes could be easier. And lots herbs: clives, Watercress, mint, etc.
Algae have been studied for bioregenerative life support, notably in ESA's Melissa project. Spirulina turns out to be one of the best candidates. It is chock-full of everything you need, including vitamins.There's a big snag though, humans cannot eat more than ~100g/day of algae (or more generally single cell proteine) without getting gout. Somewhere during our evolution we lost the ability to break down uric acid, which is a product of DNA / RNA digestion and when we get too much of it, it forms the painful crystals responsible for gout. Spirulina is an excellent food supplement, but not suitable as the main component of your diet. Plus you don't want to be eating nothing but algae soup every day.Fish on the other hand do have the ability to break down uric acid, and Tilapia thrive on a Spirulina diet, so the combination would be very useful for human consumption.
Aquaculture is a wonderful idea if you can afford the mass budget of all the water. For example, if your mission requires long term high energy GCR shielding, then you might require 5 tons per square meter of water anyway.But if you need to conserve mass, aeroponics seem to be a more promising direction. Besides minimizing water mass, aeroponics also minimizes disease spread.
Quote from: IsaacKuo on 10/07/2011 02:56 pmAquaculture is a wonderful idea if you can afford the mass budget of all the water. For example, if your mission requires long term high energy GCR shielding, then you might require 5 tons per square meter of water anyway.But if you need to conserve mass, aeroponics seem to be a more promising direction. Besides minimizing water mass, aeroponics also minimizes disease spread.All the water would be recycled.
Aeroponics requires far more resources due to slow growth times, and lower concentrations of raw materials.
Quote from: gbaikie on 10/07/2011 03:07 amDo not know how you extract CO2 from air.Activated carbon and recycle the activated carbon?Other than chemical processes [such as making methane for example]not sure how you get this impurity out of the air- 1000 ppm is .1 % and might might want to tried to get down to level of 1000 ppm.One could mix the water with the air- use cold and pressurized water- maybe? A problem is no gravity.Edit: I think growing some thing like lettuce and tomatoes could be easier. And lots herbs: clives, Watercress, mint, etc.First of all, pure CO2 is not a requirement. Algae in its natural environment works fine with CO2 in the concentration it exists in our atmosphere just like plants.Second of all, CO2 can be concentrated using filters, and a variety of other methods.Lastly concentrating the CO2 is desirable because it allows the algae to grow faster due the greater access its raw material, carbon.Like I stated before the problem with lettuce, tomatoes, as well as other more complex forms of life is that they have grow slower, require more minerals, and are more sensitive to their environment, thus they require more resources.
Like I stated before the problem with lettuce, tomatoes, as well as other more complex forms of life is that they have grow slower, require more minerals, and are more sensitive to their environment, thus they require more resources.
... if one could mix crew air with water of algae- just not sure what best way to do this in zero gee. In gravity you simply pump the air into the water- something similar those bubbly things in a fish tank.
The only filter I know that takes CO2 out of the air is a carbon activated filter. A carbon activated filter is good for taking any impurity out of the air. But these filters wear out and need to be replaced with fresh carbon activated filters. That's not a big problem bring lots of fresh filters- but getting the carbon dioxide captured from the air with these filter to the algae in the water is the part I don't know how one could do.We could skip the use of any other kind removable CO2 from the air if one could mix crew air with water of algae- just not sure what best way to do this in zero gee. In gravity you simply pump the air into the water- something similar those bubbly things in a fish tank. Perhaps one turn water into a mist- like garden hose. Do in a box and water will clump to together and you pump out the liquid water [enriched with CO2 of crew air]. If this is cold the crew air would not return to crew with much humidity and water will mix well with CO2.Edit: And/or simply remove humidity from crew air, and put that water in the algae water.
Note that if you're using tilapia for food rather than directly using the algae for food, you cut your effective productivity by an order of magnitude. Each layer of a food chain is roughly an order of magnitude cut in efficiency. In contrast, aeroponic crops can be used directly for the entire diet--including complete proteins from a variety of legumes.
Quote from: strangequark on 10/07/2011 03:24 pmYou'd think it wouldn't be that hard to remove the uric acid component, though.The uric acid is produced by the human body as it breaks down the RNA/DNA from the algae, so you'd have to somehow break down the uric acid inside the human bloodstream, or to break down the food before eating it as they presumably do for intravenous feeding. I've read there is an experimental drug that can help the body break down uric acid, but I think it has nasty side effects.And of course, that still doesn't solve the algae soup all day, every day problem.
I agree with the aeroponic potato concept. Very good staple, if you have to pick just one.
No fat, though (but fat is the most energy-dense food source, so would be efficient to transport that to Mars from Earth anyways).
Aquaculture is a wonderful idea if you can afford the mass budget of all the water.
In fact, the high productivity of aeroponics for a given system mass is the reason why NASA has devoted so much research into aeroponics...
Note that if you're using tilapia for food rather than directly using the algae for food, you cut your effective productivity by an order of magnitude.
I really think that specialized drugs like that are going to be the key to future off-world colonization techniques...
Lettuce, herbs, and tomatos ... peanuts ... beans ... potatos, rice, or wheat and you've got the basis for an tasty healthy diet. Corn is also a good food with a lot of flexibility, but it's a bit less trivial to properly process than the other staple starches.
Of course, the more variety of Earth lifeforms you bring to Mars the Moon, the greater the probability of forward-contamination of Mars the Moon.
Quote from: gbaikie on 10/07/2011 07:36 pmThe only filter I know that takes CO2 out of the air is a carbon activated filter. A carbon activated filter is good for taking any impurity out of the air. But these filters wear out and need to be replaced with fresh carbon activated filters. That's not a big problem bring lots of fresh filters- but getting the carbon dioxide captured from the air with these filter to the algae in the water is the part I don't know how one could do.We could skip the use of any other kind removable CO2 from the air if one could mix crew air with water of algae- just not sure what best way to do this in zero gee. In gravity you simply pump the air into the water- something similar those bubbly things in a fish tank. Perhaps one turn water into a mist- like garden hose. Do in a box and water will clump to together and you pump out the liquid water [enriched with CO2 of crew air]. If this is cold the crew air would not return to crew with much humidity and water will mix well with CO2.Edit: And/or simply remove humidity from crew air, and put that water in the algae water.Not that I like this idea at all but, carbon dioxide readily condenses with refrigeration and pressure so extracting it from the cabin air would not be a problem. The CO2, warmed back into a gas could be injected into a column of tank water slowly being pushed through a coil by a pump. The coil is to give it sufficient contact time for the CO2 to dissolve into the water. At the end of the coil the water enters a centrifuge where the water separates from the gases. That part is easy. Extracting the algae from the water.... that's the hard part. Too much water, too little algae. That way biofuels from algae hasn't gotten anywhere. Too hard to concentrate the algae.
Lettuce, herbs, and tomatos have low caloric content. Various legumes offer good caloric content, in the form of a good balance of carbohydrates and complete proteins. They offer a wide variety of culinary possibilities, from raw/roasted/boiled peanuts and edamame to refried beans to hummus to various masalas to peanut butter.Add in aeroponic potatos, rice, or wheat and you've got the basis for an tasty healthy diet. (Corn is also a good food with a lot of flexibility, but it's a bit less trivial to properly process than the other staple starches.)As for the culinary possibilities of algae--there is actually a good range of tasty possibilities, at least if you're into Japanese food. Wakame and nori are pretty good straight, even if they're more typically eaten with other ingredients.
Many of these things you guys are mentioning take months to grow, thus the amount of space need to sustain even a small group of people is very significant.
You should understand the algae biofuels process before you make such assertions. Watch this.
Quote from: DarkenedOne on 10/08/2011 02:56 pmYou should understand the algae biofuels process before you make such assertions. Watch this.If I recall correctly, that company went out of business. It's not that algae can't be extracted from water but that the energy costs of doing so are too high, much like ethanol.
Tell that to Brazil who get a quarter of their auto fuel (by volume) from ethanol.
Just because a company went out of business doesn't mean the concept can't be made to work. Algae is largely the source for liquid fossil fuels, after all.
Now the conversation is getting pretty far afield... But the government subsidies can make sense if relying just on the conventional fuels (fossil fuel produced in other, potentially unstable, countries) has such considerable "externalities" that have a cost higher than just paying a subsidy for the alternative.I mean, how much does it cost the US gov't to protect the Strait of Hormuz? Saudi Arabia, etc? Just a for-instance. US energy companies which refine oil from those places don't pay for that directly (they pay via taxes... hypothetically), so it's called an "externality" (a cost that someone causes but doesn't have to pay except that everyone as a whole ends up paying for it... "tragedy of the commons," etc). If energy companies (and consumers at the pump) were burdened with the full cost of using mostly non-domestic fossil fuels, it might make the subsidies for alternatives look like chump change. Anyway, trying to bring it back on-topic a little more: Solar power isn't really a very inexpensive source of power on Earth's surface (compared to some alternatives), but at least in the inner solar system (not on a planetary body), solar power is basically by far the cheapest energy source. In the same way, algae production may not compete well with fossil fuels on Earth, but that has very little bearing whether it makes sense in space.
Quote from: DarkenedOne on 10/07/2011 04:27 pmQuote from: IsaacKuo on 10/07/2011 02:56 pmAquaculture is a wonderful idea if you can afford the mass budget of all the water. For example, if your mission requires long term high energy GCR shielding, then you might require 5 tons per square meter of water anyway.But if you need to conserve mass, aeroponics seem to be a more promising direction. Besides minimizing water mass, aeroponics also minimizes disease spread.All the water would be recycled.That's not the issue. The issue is that algae require a lot of water to live because they must be immersed in water. Aeroponic plants do not need to be immersed in water. Instead, they are immersed in air, which has a far lower density than water.Note that if you're using tilapia for food rather than directly using the algae for food, you cut your effective productivity by an order of magnitude. Each layer of a food chain is roughly an order of magnitude cut in efficiency. In contrast, aeroponic crops can be used directly for the entire diet--including complete proteins from a variety of legumes.
Now if there was some way to convert the algae into a tasty vegetable, which we can eat more than 100g of? I suppose mushrooms can do this without additional energy?
1. Have some tilapia, from a supermarket, produced under the lowest input, lowest maintenance conditions that the profit motive can achieve.2. You are not allowed to use any other additives, ingredients or spices, not even salt.3. Read up on tilapia.4. Post again on the topic of tilapia and share your findings.
If chicken can convert algae at 30-40% efficiency compared to 60-70% for Tilapia, it just means chicken will cost double the price of Tilapia. But both will be more efficient (and hence cheaper) then real vegetables.So, chicken or Tilapia, bread from algae, and tomatoes. Serve with spices of your choice - they weigh nothing and have a long shelf life, so can come from Earth.
Quote from: alexterrell on 03/23/2013 08:23 pmIf chicken can convert algae at 30-40% efficiency compared to 60-70% for Tilapia, it just means chicken will cost double the price of Tilapia. But both will be more efficient (and hence cheaper) then real vegetables.So, chicken or Tilapia, bread from algae, and tomatoes. Serve with spices of your choice - they weigh nothing and have a long shelf life, so can come from Earth. I don't know about Tilapia, but I would ask how you plan to transport the first chickens from Earth to Mars? It's my understanding that fertilized eggs won't work. They will either hatch or spoil.
It is quite well known that Tilapia tastes of almost nothing. BTW that is why I don't buy them in the shop.
Quote from: alexterrell on 03/23/2013 08:23 pmSo, chicken or Tilapia, bread from algae, and tomatoes. Serve with spices of your choice - they weigh nothing and have a long shelf life, so can come from Earth. I don't know about Tilapia, but I would ask how you plan to transport the first chickens from Earth to Mars? It's my understanding that fertilized eggs won't work. They will either hatch or spoil.
So, chicken or Tilapia, bread from algae, and tomatoes. Serve with spices of your choice - they weigh nothing and have a long shelf life, so can come from Earth.
Quote from: mmeijeri on 10/07/2011 03:20 amAlgae have been studied for bioregenerative life support, notably in ESA's Melissa project. Spirulina turns out to be one of the best candidates. It is chock-full of everything you need, including vitamins.There's a big snag though, humans cannot eat more than ~100g/day of algae (or more generally single cell proteine) without getting gout. Somewhere during our evolution we lost the ability to break down uric acid, which is a product of DNA / RNA digestion and when we get too much of it, it forms the painful crystals responsible for gout. Spirulina is an excellent food supplement, but not suitable as the main component of your diet. Plus you don't want to be eating nothing but algae soup every day.Fish on the other hand do have the ability to break down uric acid, and Tilapia thrive on a Spirulina diet, so the combination would be very useful for human consumption.Well that is what I was talking about when I mentioned food processing. I was imagining that algae would not be terribly tasty. The raw material is there we just need to do food processing to turn it into something useful.
Spirulina bioreactorsThe ‘Melissa loop’ is about to take off. All around the world – and soon above it – key pieces of the puzzle are being tested to see how they fit into the whole. First up is a photo-bioreactor that uses light to power organisms for turning unwanted carbon dioxide into something we can use. Bioreactors cultivate organisms in closed containers but getting a species to thrive is no easy task. As the occupants grow they need space and different lighting. And continuously drawing the good stuff out of the reactor ready for human consumption cannot be allowed to disturb the mini-ecosystem. The Melissa team has made great progress in this domain and is ready to test their system in space. In the next 12 months they will send Spirulina algae to the International Space Station to see how well it grows in microgravity. Spirulina has been harvested for food in South America and Africa for centuries. It turns carbon dioxide into oxygen, multiplies rapidly and can also be eaten as a delicious protein-rich astronaut meal. The first experiment will simply assess how Spirulin aadapts to weightlessness so researchers can fine-tune the unit. The next step is a hands-on test: an experiment that mimics astronauts’ breathing will be connected to the bioreactor so the Spirulina can grow on a steady stream of carbon dioxide, delivering oxygen in return. If these early tests in space go well, the team will be a long way towards the ultimate goal of recycling carbon dioxide, water and organic waste into food, water and oxygen