Growing Plants In Lunar Gravity

smooth wombat writes "If everything goes according to plan, an experiment designed to test whether plants can grow in the limited lunar gravity will hitch a ride with a competitor for the Google Lunar X Prize. 'The current prototype for the greenhouse is a 15-inch-high (37.5-centimeter-high) reinforced glass cylinder that's about 7 inches (18 centimeters) wide on the bottom. Seeds for a rapid-cycle type of Brassica plant — basically, mustard seeds — would be planted in Earth soil within the container.' The press release from Paragon Space Development Corporation outlines its partnership with Odyssey Moon to be the first to grow a plant on another world. In addition to the experiment, Paragon will be helping Odyssey with the thermal control system and lander design. To win the prize, Odyssey must land its craft on the lunar surface by the end of 2014."

Plants grow in microgravity.

[ravenshrike]

Thus any differences between earth grav and 1/6 earth grav are likely to be negligible. Dumbest experiment ever.

Re:Plants grow in microgravity.

[megrims]

From TFA:

"Plants have been grown in essentially zero gravity and of course in Earth gravity, but never in fractions of gravity," said Dr. Volker Kern, Paragon's Director of NASA Human Spaceflight Programs who conducted plant growth experiments in space on the US Space Shuttle. "Scientifically it will be very interesting to understand the effects of the Moon and one sixth gravity on plant growth."

I'd be curious to see what kind of different plant structures emerge.

Re:Rapid growth

[Psychotria]

I would think that plants would grow faster with little to no gravity.

Maybe. But the question might be more related to how healthy or productive the plants are. Even on Earth we can accelerate plant growth by (as an example) growing light adapted plants in low-light conditions with ample nutrients, or by introducing growth hormones such as gibberellins or adjusting the photoperiod. Often the plants are not 'healthy' though. Stem elongation, weak cell walls, abnormal tugor, reduced or inhibited fecundity all may exhibit themselves. So, to me, the question isn't whether it's possible (it probably is), but whether or not the result is a healthy plant that is able to reproduce and/or meet some other goal like production yields (in the case of vegetative growth then I guess that could easily be met, in the case of grain [seed] production I think it might be harder...)

Re:What about...

[MichaelSmith]

Couldn't this same experiment be done on a centrifuge in Earth's gravity? Centrifuges usually are used to increase apparent gravity, but if it were shaped so that the plant and soil faced outward, at the right speed, wouldn't one be able to mimic that 1/6 g?

No. A centrifuge can only add to gravity.

Re:What about...

[dkf]

That of course assumes the extrapolation is meaningful, but it might give a rough indication of what to expect with very little expenditure.

That's been done I bet, but you still need to run the experiment to check whether that extrapolation really is meaningful. There isn't really any substitute, because the fundamental problem with all models (and theories and extrapolations) is that they leave out details, and if you push the model far out of where it was designed for you can get other effects dominating.

For example, you can extrapolate gravitation down to the nanometer scale, but that doesn't mean that it lets you fully understand the behavior of matter in that domain. Electrostatic effects tend to rule at that level instead, yet they're not part of any (sane) model of gravitation that I've heard of. Overall, this just tells you to beware of taking models too far.

Re:Lunar sunshine and lunar soil

[Ernesto Alvarez]

That filter already exists. Solar cells work fine on the moon. That means you can use it to recharge batteries, and use those batteries to power lamps suitable for growing plants. It's a clumsy way, but doable.

the most bothersome part of this is the ISS

[WindBourne]

It was suppose to have a centrifuge module added (CAM). It was designed SPECIFICALLY for growing life in varying Gs. From that we would know exactly how certain life will respond to the moon, mars, or even something in between so that we can design a ship for long term travel. It appears that NASA may have the shuttle thrust upon them for another year or two. If so, I would like to see us restore the CAM and put it up there. While the original module will not work (been exposed to the elements in japan), we have multiple modules that would work. Heck, we could put up a Sundancer or a BA-330 along with the centrifuge. Then move a number of the units from Columbus to the Bigelow and then put the centrifuge in Columbus. This is probably one of the single largest reasons to have the ISS. This kind of work can not be done on the moon. Of course, I would suspect power would be a problem. Russia no longer has their solar cells, and we are adding more power hogs with out increasing the cells.

Re:Lunar sunshine and lunar soil

[spaceman375]

The biggest problem with the soil is that it's sharp. There's no weathering on the moon; the "soil" is dust and grit with very sharp points and edges. The plants would be enduring constant irritation and injury.

Of course, you could sift the dust through a concentrated beam of sunlight and melt it into little spheroids. That would still be cheaper than grinding or importing something softer. The point is, you'd have to process your lunar resource of choice somehow; you can't use it "straight up."

Re:Moon Dirt

[AJWM]

Back in Apollo days they did this. Actually as I recall they didn't try growing them in pure Lunar soil (that would require too much of a scarce commodity) but in a mix of Lunar soil and sterile Earth soil. The initial objective was to make sure that Lunar soil (and any possible unknown organisms in it) wouldn't have any adverse effect on Earth plants -- but they discovered that the plants actually grew better. Turns out Lunar soil is rich in (inorganic) nutrients just as volcanic soils are.

The Moon is low in nitrogen and carbon, so those would have to be added to Lunar soil for good growth.