Space Food From Space Farms 168
Modern Farmer magazine has an article about NASA's efforts into growing food in space, a slow, difficult process that's nonetheless necessary if humanity is to have any significant presence away from Earth's surface. Quoting:
"This December, NASA plans to launch a set of Kevlar pillow-packs, filled with a material akin to kitty litter, functioning as planters for six romaine lettuce plants. The burgundy-hued lettuce (NASA favors the 'Outredgeous' strain) will be grown under bright-pink LED lights, ready to harvest after just 28 days. NASA has a long history of testing plant growth in space, but the goals have been largely academic. Experiments have included figuring out the effects of zero-gravity on plant growth, testing quick-grow sprouts on shuttle missions and assessing the viability of different kinds of artificial light. But [the Vegetable Production System] is NASA's first attempt to grow produce that could actually sustain space travelers. Naturally, the dream is to create a regenerative growth system, so food could be continually grown on the space station — or, potentially, on moon colonies or Mars. ... Plant size is a vital calculation in determining what to grow on the space station, where every square foot is carefully allotted. Harvest time is also of extreme importance; the program wants to maximize growth cycles within each crew’s (on average) six-month stay."
Re:Fertilizer... (Score:4, Informative)
Re:oxigen (Score:5, Informative)
They are looking to reduce maintenance and power use. Aero and hydroponics requires constant power. Dirt medium does not.
Re:oxigen (Score:4, Informative)
Aeroponics has containment issues. If you're misting water constantly, it's going to go everywhere. In fact it's probably not going to behave quite right either since the water doesn't fall - droplets can aggregate and just float around forever. So you're then looking at a complex vacuum system to keep the water moving through properly.
Much easier just to absorb it into something near the plant roots.
No need for fertilizer (Score:2, Informative)
The soil replacement substrate they are testing (arcillite) is highly absorbent and probably is pretreated with the fertilizers. I know that similar experiments (SVET, russian ) were done on the Russion Mir station (my father was leading the team that developed the soil substrate). They used naturally occurring mineral (zeolite) which is extremely good absorbent. You can pretreat it with a fertilizer mix and it will leach small amounts of nutrients and support plant growth for years. All you need to do is add water. The zeolite is also very light - the dry stones will actually float when placed in water, until they absorb enough of it to sink. The zeolites and I assume the arcillite substrate that NASA is testing can also serve as base for soil formation. On long missions you can mix them with waste and let it rot. Because of their absorbent properties the zeolites will actually reduce the smell that comes out of the mix. I would guess that in a confined box with no external supply of fresh air, this would be quite an advantage.
Here are some references for the substrate description [google.com] and the experiment results [nih.gov].
Re:Fertilizer... (Score:4, Informative)
Full text of the story, [readanybooks.net] thank you, that was one I hadn't seen.