Plant Growth in Space

[Clockwork]

Hi KSP science community,

Do any of you know any good articles on plant growth in space? I'm working on a mod for KSP called Kerbal Botany Expansion, which, as it sounds, adds plant science into KSP, but I really have no idea how plants grow in space or exactly how I want the plant study labs to work. I know that the science is going to be generated over time, but I am not exactly sure what should be said about the Plants at each different stage, If you have information on this topic, I would love to hear it and figure out a way to incorporate it into my mod! If you have ideas for my mod specifically, you may want to consider posting that in the development topic of my mod (Here). I would love to discuss applications of botany in space and how we can adapt it for KSP.

Edited November 10, 2016 by Clockwork

[kunok]

I'm NOT a biologist

Well, for a start we only have data about plant growing in 1g, and a little of 0g.

IIRC one of the biggest problems is that the plants are in a can atmosphere, the don't have a nearly infinite atmosphere to emit ethylene, so you need to filter it (that's an hormone to mature food, is the one used to control maturation in stored food, the tech is said to be developed researching plant growing in the MIR)

Other problem was doing a good subtract for the roots, but that's only a problem with 0g IIRC.

I'm sorry I don't remember the article where I have read all of this.

You can put the botany laboratory to do a series of experiments each of them takes some time.

Can be something like this (is close to what happened in real world), but with better english:

-Plants have matured before complete grow, dying before they had seeds, we need to research what is happening.

-An abnormal grow in the ethylene levels inside the atmosphere, produce plants to mature too early. This ethylene is produced by the plants itself. We need to look for a way to control the ethylene levels.

-After adding an ethylene filter, plants grow much better, some of them produced seeds. We would take some of the seeds for further study, and the rest we would use to plant the next gen of plants.

 

I would like to research a little myself, If I have time this weekend, I will post something

[KSK]

Sounds like an interesting mod. KSP science  - now with actual game-relevant science!

The Wikipedia article looks like a useful start (https://en.wikipedia.org/wiki/Plants_in_space) although it's not particularly detailed. NASA also has various articles on plant experiments carried out on the ISS but from what I can see these tend to be public awareness pieces without too much hard detail.

Like @kunok I'd like to do some research on this. In the meantime, some possible research topics:

Zero-g hydroponics. More of an engineering problem (if we assume that kerbals have already developed hydroponic technology for growing plants on Kerbin) but what's the best way of ensuring adequate contact between plant roots and the hydroponic medium in zero-g? How do we contain, clean and recycle that medium? 

Germination. Does it work in free-fall? Does the lack of gravitational cues affect early plant development (shoot goes up, roots go down)?

Germination 2. Once we know that plants will germinate in free-fall, we need to find ones that will germinate reliably and develop into suitably vigorous plants.

Morphology. What does a space-grown plant look like in terms of distribution of shoots and leaves. Do you get long spindly plants or nearly-spherical bushes. How does that affect their ability to photosynthesize and grow?

Crops?  Do staple kerbal food crops grow in free-fall. Are space greenhouses a realistic prospect?

Nutritional content? How does this compare between Kerbin grown and space grown crops. Do space grown crops accumulate excess nutrients (vitamin A would be an example for Earth plants) that could actually be toxic to kerbonauts.

Environmental factors. Kunok's ethylene example is a good one, although as a minor nitpick, I would expect that normal air scrubbers aboard a spacecraft would take out the ethylene quite handily. The point still stands though - are there any problems we have to account for simply because we're growing plants in a very constrained, closed environment?

[78stonewobble]

Well is there any hindrance in carrying seeds to eg. another planet or place with gravity? Because if not, there's nothing stopping us from breeding different plants specifically for a zero-g enviroment.

[kerbiloid]

In zero-G plants grow towards the light source, and seeds must be oriented with head to light, otherwise they won't grow. (Salyut experiments)

Edited November 10, 2016 by kerbiloid

[KSK]

14 minutes ago, kerbiloid said:

In zero-G plants grow towards the light source, and seeds must be oriented with head to light, otherwise they won't grow. (Salyut experiments)

Interesting. And that sounds like exactly the kind of thing that @Clockwork was looking for! Simple experiment, fundamental result, easy to write a two or three line summary that could go into a KSP science report.

[kerbiloid]

Also they had a problem with capillary pipes in the ground (to deliver the water). They worked as overpowered pumps in zero-G.

The walls of the original vat were designed to repel water. Version 2.0 vat had walls attracting water.

Skylab experiments also proved "head to light" requirement.

Edited November 10, 2016 by kerbiloid

[Clockwork]

Thanks, Guys! I'll start finding a way to implement this stuff right away, so correct me if I'm wrong, but here's a list of potential data that could be collected/tested in the botany lab:

-Seed Orientation: if the seeds aren't pointed toward the light source, they won't grow

-Nutritional Content: what are the differences in composition in a plant grown in space to a plant grown on earth

-Inability to grow: are there any species/family of plants that have always failed to grow in space, if so a similar species/family of kerbalized plants will be implemented into the mod

-Atmosphere content: even if the atmosphere is ideal to begin with, constant exchange of gasses within the plant may make the mix less than ideal for the plants if not properly maintained

-Germination: Are germination rates affected in space? Are the plants germinated in space as tough as plants germinated and matured on earth

also @kerbiloid could you explain what you mean by having problems with capillary pipes?

Edited November 11, 2016 by Clockwork

[kerbiloid]

7 hours ago, Clockwork said:

what you mean by having problems with capillary pipes

According to the book, in the first version of Oasis device the soil layer was pierced with capillars (don't know, if they mean artificial pipes or special porous ground structure) which were (by design) to deliver the water more effieciently. But in zero-G they were sucking water as pumps and got overpoweredwatered.

[KSK]

Yep - surface tension can do some funny things in zero-g. I'm not surprised that an irrigation system designed to rely on it would be much more powerful than expected.