John : Good afternoon from Kennedy Space Center and welcome to a Webcast Series of the International Space Station — A Home in Microgravity. My name is John Rau and I'll be your host for the next hour.

Today's Webcast entitled, International Science Research will be a discussion about science research from Canada, Italy, and Russia. Mike Dixon, a professor from the University of Guelph in Ontario, Canada will be our main guest for this afternoon. Also, we have taped interviews from Sabina [Donne] from Italy talking about her research at Kennedy and [Yuli Berkovich], a Russian scientist from Moscow, talking about his work. However, before I introduce Mike and he talks about himself, let's take a look at today's schedule.

We'll start off first talking about controlled environment systems, which is similar to advanced life support, which we talked about in previous Webcasts. Mike will then talk about his research at Kennedy Space Center, the Mars Greenhouse, for instance, followed by our first video clip by Sabina [Donne].

Mike will also talk about his research in Canada, Tomatoshphere and other projects. And then finally we'll have our second video clip of Yuli talking about his new plant delivery system, and then close the discussion of the Webcast by talking about long-duration of space expeditions to Mars.

At this time I'd like to introduce our guest for today. Once again, his name is Mike Dixon. He is a professor from the University of Guelph in Ontario, Canada on a fellowship here at Kennedy Space Center. Mike could you tell our viewers a little bit about yourself and what you do here at Kennedy?

Mike: I'm the Director of the Controlled Environment Systems Research Facility at the University of Guelph. The kinds of research objectives we deal with there are what do plants do for us in space? How can we use plants to take advantage of the life support contributions that they can make? And the kinds of research facilities we have in Canada are similar in many respects and complementary to the research facilities here at Kennedy Space Center. So I have been collaborating here since December on a six-month sabbatical leave from the University to collaborate with my colleagues here, Ray Wheeler and Phil Fowler and [Kadim Rigoloff] in issues related to building a greenhouse on the planet Mars.

John: Thanks, Mike. There is a picture here, actually, if you could back up one. Thank you, Mike.

Mike: This is the newly opened Controlled Environment Systems Research Facility at the University of Guelph attached to the Bodie Building Complex and it doesn't look like much, I know, this sort of tin building here, this steel building, but inside is some of the most sophisticated research facilities available on earth to investigate how we're going to grow plants on the planet Mars.

Here is the first prototype variable pressure research chamber for growing plants under conditions that would be similar to those that we would use on the planet Mars and the kinds of systems that we would be requiring there to successfully grow plants and have them form parts of our life support.

John: Thanks, Mike. Let's start things off by talking about controlled environment systems. [How similar is that to] some of those like to advanced life support? Is there a big difference [there]?

Mike: Advanced life support, I guess, requires controlled environment systems to take advantage of how plants can help us survive off this planet just as they help us survive on this planet. So the controlled environment system is like a greenhouse where you control the temperature and the humidity and the nutrient solutions like the water, carbon dioxide, all of the food that plants require.

And just take that a step further and consider an extreme environment like some place off this planet and the greenhouse that's required there. So that kind of controlled environment and all the technologies that would be required to help you do that.

John: Okay. Let's take a quick look at some of the research you have done here at Kennedy Space Center. We have actually a cooling [curb] apparatus. Did I say that correctly?

Mike: That's right. We're starting at the bottom of the heap, really, in terms of the kinds of information we need to know. We need to know what happens.

In this case, we're looking at different pressure and that is an environment variable that we're considering. So as you reduce the atmospheric pressure, the physics of how you deal with carbon dioxide uptake on plants, heat exchange, temperature control, all of these things start to change.

And this little apparatus is actually a small heater on a wand that you can see there and that heater swings in underneath a leaf, sort of a leaf, it's a brass bottle of a leaf, and we measure the temperature of that leaf and heat it up just a little bit and then swing the heater away. And off in the corner of that picture, you can just see it, is a piece of a shuttle tile which we're using as a heat shield because when we measure the temperature difference, the temperature effect on that little model, we don't want the heater to be anywhere in the picture, if you know what I mean. It needs to be out of the way and not influencing the temperature changes that the model leaf are experiencing.

So our friends over in the shuttle lab made up this little heat shield for us out of shuttle tile material so we could swing it away and hide it from the leaf under the conditions inside the chamber. There's actually a movie of this, a little wave file that I can attach to our Web site at some point and so you can actually see it in action what it's doing there. But I'm just throwing a switch swinging it under the leaf and away and into the shuttle tile to hide it.

Just to explain exactly what's happening there, as the leaf cools down under different environment conditions of different pressures, the cooling rate changes and that allows us to calculate the influences that similar physical activities would have with real plants. Real plants have to deal with cooling as well and heating up and having gases diffuse in and out, so we need to understand all of the physics of how plants will react to these different atmospheric pressures and this is one of the techniques that we're using to investigate that.

John: Plus you don't have to worry about the plants ever dying; it's always there for you. We have another device here.

Mike: This is really, really simple and it's a temperature sensor, but it's held up in a little glass rod so that my hand isn't influencing it and on the end of that glass rod, that little wire that's touching, in this case, the tomato leaf, is a thermocouple. And that thermocouple, a very sensitive temperature measuring device, it's simply a little metal thermometer, and I can read the temperature of the leaf in that case and look at the influences that the environment are having on that variable, which is pretty important.

John: Actually you brought your thermocouple.

Mike: I brought it along and we can play with it here. I've also stolen a plant from the pile plants that we were playing with downstairs. This is a pepper plant. I know we're talking about tomatoes a lot today and tomatoes are a very popular crop, but peppers are also a candidate crop species for applications in space and this one actually has a little pepper on it. This is a banana pepper and the way you would use this is you would simply go in and touch the leaf surface and this is such a sensitive little thermometer that it will instantly tell you the temperature of the leaf surface and that's a very useful number to know because it tells us how the plant is dealing with gas exchange, water exchange and how it's dealing with its own temperature control.

John: Let's move along here. I actually have some pictures of your tomato plants here in your lab. Correct?

Mike: That's in the lab. We've got tomatoes and peppers and lettuce. Those are just candidate crops basically. There's a long list of candidate crops that are applicable to the space situation and these are just some of them. The list is growing all the time as probably three dozen or so crops including wheat and potatoes and all kinds of edible crops. Peppers that we have here and tomatoes that you see in that picture are among the crops that we are looking at specifically at the moment and this is just a small jungle of tomato plants in the lab at the moment.

John: Here's a side angle, a better angle of it.

Mike: Right.

John: What type of lighting are you using here?

Mike: Those are relatively conventional supplementary lights that you would find in most greenhouses, especially in Canada, and they are high-pressure sodium lights. That's why the picture looks a teeny bit orange to most of us. High-pressure sodium lights tend to look a bit orange. If you've ever flown into London, England, they use high pressure sodium lights on their streets and you'll see these sort of orange streets at night. That's the same kind of light that we are using in this case.

John: Is that actually a better light to use than a fluorescent one?

Mike: Well, high-pressure sodium is about the most efficient light for growing plants under controlled conditions like this. It has a good color spectrum. It provides most of the colors that plants need to grow and more so than, for example, fluorescent lights and other kinds of lights, but that doesn't mean that they don't all have some contributions or some applications for controlled environments in this case.

John: Moving along here actually to the next — we have another apparatus or piece of equipment here. Explain this one, please.

Mike: This is another gadget that, I mean, what you're seeing here is an array of techniques and systems that we're using to measure how the plants respond to the different environment challenges that we set up for them under the conditions that they might experience in a Martian greenhouse.

As an example, a Martian greenhouse is just one of the issues that we're looking at now, but there are a long list of different applications in space that we can consider. This device that you're looking at is called a psychrometer, which doesn't mean much to most people, but basically it's a very small chamber that what you're seeing there is about the diameter of a quarter, but the actual end of the chamber is even smaller than that and that's what you expose to the plant tissue.

Basically, what it measures is how well the plant is doing with water, whether it's under drought stress or wilting stress, those kinds of things. It measures the response that the plant has to the availability or atmospheric demand for water.

John: And who developed this?

Mike: Actually it's based on a technology that came out of plant physiology from the early 50's, but this particular application of it was something I developed as a graduate student in Scotland.

I've got one of them here and I can just show you sort of how we would have employed it in reality to this Pepper Plant. It's called a stem psychrometer and the reason for that is obvious in a moment. You simply take it here and tighten up this little clamp and attach it to the stem of the plant. Now what I didn't do was I didn't scrape away any of the bark or the covering on the plant here. You would normally do that. I just don't want to hurt this poor little guy at the moment because he's really not in an experiment yet, but normally you would just scrape away a little bit of the bark there and attach this device directly to the exposed area of the water conducting tissue, the xylem, in underneath the stem.

And eventually, this instrument comes into equilibrium or it starts to measure how the plant is dealing with water. So as the water comes up from the roots, down in this area, and up through the stem and evaporates from the leaves, it creates a suction force inside the stem and we can measure that by measuring basically the humidity that's in relation to the water in the conducting tissue.

And that's just another measurement that we're interested in making to evaluate how plants respond to the environment challenges that they will be presented with when we take them off this planet. So how the plant responds in terms of water use is a very important number that we can take away. Leaf temperature, water stress levels, these are all things that help us understand more clearly how best to use plants in space.

John: We have another piece of equipment that I'd like to show you. Our last piece here at Kennedy. This is called what now?

Mike: That's the guts of the Mars dome. What you see there is a mess of wires and tubes and pots that plants grow in.

There it is all fully dressed with a lot of plants in it. The plants are all in these pots and those pots actually fit on balances that weigh how much the plant weighs that weigh its water use so you can tell when to water it.

And these are little pumps, little valves that are connected to pumps that will deliver nutrient solution directly to the plants.

That tall column that you see there, this whole thing here, is part of the environment control inside the dome and it's designed to cycle the water so it takes the water that evaporates from the leaves of plants in transpiration, the process of transpiration, and condenses it through that system on a coil and returns it back to the nutrient tank that feeds the plants their water and root zone. So it just runs water around in a great big circle.

John: Now what type of plants can go into this Mars dome? Actually pretty small.

Mike: Unfortunately, it's limited in size. The diameter of this particular system is about four feet or just over a meter for anybody who's in the metric system. And the height of it is probably about three feet, two and a half to three feet. So we can't get very large plants into it, but we can get, for example, this plant will fit quite nicely, this pepper plant and similar sized tomato plants and those are what we intend to use at the moment. But any range of the variety of candidate crops, not corn, unfortunately, because corn will grow a little too big. But eventually we will have systems that will allow us to test virtually all of the candidate crops that are available to us.

John: What exactly is the Mars dome designed for? What will you be using this for?

Mike: It's mainly designed to look at the kinds of greenhouse conditions that we would have to create on Mars in order to reliably and indefinitely grow plants for life support on Mars. And those conditions include lower pressure and different atmospheres. Most atmospheres comprise largely of nitrogen and oxygen and carbon dioxide and a whole bunch of trace gases.

On Mars, the atmosphere is almost entirely carbon dioxide with a little bit of nitrogen and aragon and then some really, really minor traces of other things. That is not a good enough environment, so we will have to create a different environment in here and it's likely that plants don't actually need everything they have in Earth's environment, so we'll investigate different atmosphere compositions in this dome and come up with the most efficient and economical way to control environment composition on Mars, as well as pressure.

This is designed to go inside of a much larger chamber which we can pull down to a vacuum and then isolate the water and have the water running around inside this system. So it'll help us to determine basically the engineering specifications for that first greenhouse that we build on the planet Mars.

John: Now will this protect it from radiation, for instance?

Mike: No. That's a real good question. It's entirely possible that since the Martian environment is so thin. It's basically 1/100 or less of Earth's atmosphere density, so the protection from cosmic radiation, space radiation is a lot less than it is here on Earth. And if you think you get a little sunburn with too much ultra violet exposure out here on the beaches of Cape Canaveral, the beaches of Mars will give you a much deeper sunburn.

So radiation issues are certainly very profound ones and it is entirely possible that the greenhouse we eventually deploy on Mars will have to be under ground. Simply to get away from the radiation and we'll have to develop alternative means of lighting the plants, either lighting systems, or unconventional artificial lighting systems, or means of capturing solar radiation on the surface and piping it down perhaps with fiber optics, those kinds of things. And all of these technologies are currently under investigation.

John: Would it be possible to put like a black dome, for instance, to protect it from the radiation? Would that help it all?

Mike: There are probably some materials. And, again, materials that are being investigated to save us from radiation and still allow some sunlight to come through, that's probably quite a big challenge for the material science folks, but you never know. Technology is growing at a pace that you can't possibly imagine, I guess, but you never know.

John: Before we break to our first video clip with Sabina [Donne], let's break to the chat room and ask a couple of questions here. I know you had a question. What kind of vegetable will you be eating when you're living in microgravity? Bigger or smaller than we would grow here on Earth? And will they take longer to grow than here at home?

Mike: Well, the size shouldn't be influenced much by microgravity. The duration to grow them will depend entirely on how much light and environment control you can bring to bear on the plant growing system. Theoretically, you should be able to grow them at least in the same period that it takes to grow them in a similar kind of growth chamber here on Earth, as far as the kinds of vegetables, virtually everything that you can imagine.

John: As long as it fits in one of these.

Mike: As long as it fits into whatever system we end up deploying as a plant growth system and the issue of microgravity, though, is a toughie. Microgravity, as all of you are aware, imposes lots of significant challenges on dealing with, for example, water. I mean you can't just come and pour water on the root zone of this plant because it will all just float away.

And so when you finally get to Yuli Berkovich's work, he's looking at ways to deliver water to the root zone of a plant without having it sort of pour out all over the space station. And that's quite a technical challenge. So in most of our work, we're considering applications where microgravity is not the problem.

We're considering the Mars surface where you've got about a third of Earth's gravity, so there is an up and a down. And even on the Moon, there's an up and a down. It's not much, but it's better than on the station where there essentially there is no up or down and the technical challenges of dealing with that are just a little bit too tough for me at the moment.

John: That's the only place you have, though, for testing, right?

Mike: In the near term, yes.

John: Here's a question for you. Will there be birds in the microgravity garden?

Mike: No. The short answer is no. In the near term, food is what drives the whole equation and really it's only edible crops that will be considered in the near term, mainly because you've got to eat them. Other organisms like birds and even insects, insects are certainly considered. You need insects and you need microbes, but other complex organisms like birds, I have a feeling that's probably a little further off than I can project.

John: Actually, I'd like to break now to our first video clip. Like I mentioned before, her name is Sabina [Donne]. She will be talking about her science research here at Kennedy Space Center, which is a plant experiment comparing different CO₂ levels in plant growth. Okay. Here's the video clip.

Sabina: My name is Sabina [Donne]. I am a Ph.D. in farm ecology. I'm from Italy. I'm here with a fellowship from [inaudible]. We studied the carbon and water exchange of the natural eco system. It's the crop [inaudible]. And this is my working station. This is where I collect all my data. [inaudible] the concentration of water and carbon and air and the [inaudible] all the time. [Inaudible]

Another important part of my system is the sonic anemometer. In the same place, there is also the intake of the air because it's from the measurements of wind and of the air content and [inaudible], so that's carbon. We can measure noise, but this eco system is taking carbon and storing carbon [inaudible] later in the soil or [inaudible] been using carbon.

Part of my studies is an [open-up] chamber, but in half of them, the air is changed. The carbon dioxide is [inaudible], which [inaudible phrase] (wind factor blowing hard in the background — makes speaker sound inaudible).

Thank you very much to my peers at the Kennedy Space Center. It was very nice. I learned a lot. In two weeks, I will be back to Italy, but I hope to come back soon.

John: Okay. That was a very interesting clip and I enjoyed talking to Sabina about her research at Kennedy Space Center. I would like to thank her once again for taking the time out of her busy schedule and helping us with today's broadcast. Also, I'd like to mention if you would like to talk to Sabina about her research, she will be having a follow up chat on the 10^th of April at 1:00PM Eastern, 10:00AM Pacific, so save your good questions for her. She'll be more than happy to help.

Mike, I have one quick question before we move along here. From Samantha over to the chat room from the 8^th grade, she wants to know, have you ever worked with Sabina or do you know anything about her research here at Kennedy?

Mike: Well, certainly I've been exposed to most of the research activities here at Kennedy.

And, in fact, we've been sort of threatening to get together for quite a while now in terms of some of the technical objectives. The work that's happening out at what we call the C0₂ site, the enhanced C0₂ site, has some relevance because growing plants at higher levels of carbon dioxide will have some implications or some impact on how they deal with water. So the technologies that we might use in the different measurements, the different kinds of questions that Sabina and her group are asking and the kinds of questions that I'm working with in collaboration with the Kennedy group are different. We're looking at water and we're looking at atmosphere management and they're looking at C0₂.

However, the kinds of techniques that we would use would be very similar. In fact, I'm jealously looking at her sonic anemometer. We could certainly use that in the Mars dome to measure wind speed changes at different pressures because it's profoundly influenced by pressure and the influence that has on the plants and ultimately on the water. So there are lots of technical collaborations that we could engage in and just haven't got around to yet because we're all running around being very busy. OK?

John: We should actually move along here to your research from Canada. And there's a project called Tomatosphere. Is that correct?

Mike: That's correct. Tomatosphere obviously revolves around tomatoes and tomatoes are an extremely popular candidate crop. I hesitate to say that I don't like tomatoes myself, fresh tomatoes, that is. I'll eat ketchup or any form of cooked tomatoes, but fresh tomatoes just don't agree with me for some reason and never have. Having said that, tomatoes are nevertheless extremely important and a useful crop for advanced life support applications and they're one of the candidate crops that we have spent quite a bit of time on. And in collaboration with the Canadian Space Agency in Heinz, Canada and a long list of sponsors of this project, we a year or so ago sent a whole pile of Heinz tomato seeds up into space with a Canadian astronaut shuttle mission on the Endeavor.

The experiment was very simply what does exposure to the conditions in space, specifically cosmic radiation and to a lesser extent microgravity. What does that do to the seeds and does it change their germination rates, their viability, their health, their vigor? Does it have any impact on that? When these seeds came back from space we distributed them across Canada to almost 3,000 classrooms, 60 or 70,000 thousand students between grades 3 and 6 and they did the experiment along with us at the University of Guelph and grew tomato seeds, measured their germination rates, reported the results on the Web site, the tomatosphere.org Web site.

And we're now, in fact, I've just come from a teleconference with the Tomatosphere committee with the Canadian Space Agency, Bob Thirsk is the astronaut involved and the long list of collaborators and we're planning Tomatosphere 2 and that's happening today, as a matter of fact. So we're going to do this again and send some seeds to the International Space Station for a much longer period that is more like the kind of exposure they would get, for example, on that six-month trip to Mars. And see what that does to their germination and their vigor as a contributor to the life support mission.

John: We're showing you, we have a picture behind us, so that would be one of the classrooms that participated?

Mike: That's one of the primary schools. I can't honestly remember which one, but that's one of the primary schools that participated in the project and the students grew each of the seeds and they had four different treatments and they grew them up in these little peat pellets and reported their results on the Web site.

John: Here's another picture.

Mike: This is in my lab back at the University of Guelph and you can't really see, but behind us, me and the student here, this student is actually the grandson of one of the participants and the sponsors in the project and he came to visit the lab and so we took him around, too. But behind him is that blue machine that was actually used to treat the tomato seeds that had gone up into space and between us we're holding one of the posters that the Tomatosphere Project created.

John: Actually the last picture I have. Are these the plants grown?

Mike: Yeah. Some of the graduate students in the program stole some of the seeds and planted them in the garden outside the greenhouse at the University of Guelph and here they are.

John: Actually I'd like to answer a few more questions from the chat room before we move on to our second video clip with Yuli. Here's a question: To what degree is naturally occurring carbon dioxide, oxygen, and water going to be found?

Mike: I presume they mean on Mars.

John: Right. I presume, yes.

Mike: Well, as I said, the atmosphere on Mars is almost 95% carbon dioxide. Having said that, that atmosphere is extremely thin. It's only 1/100 or less of the atmospheric concentration of gases on Earth. So even that 95% carbon dioxide is really a very small amount of it. There's very little oxygen available. Water is still the $64,000 question.

We assume that water has been a part of the history of Mars, the ancient history of Mars, because of the way it looks sort of water etched on the surface. And we hope that there are reserves of water underground that we can tap into and take advantage of as a resource on that planet. So carbon dioxide will certainly be one that we can pull from the atmosphere and feed to our plants because they need carbon dioxide and they'll give us [inaudible]. And we're hoping that there's still some there deep under the surface that we can tap into.

John: From Patty: how do you select the plants that you'll take to space? Does it have to do with the nutrients, for instance, for us to eat?

Mike: Yes. Certainly the nutritional value of the crop, but also its appeal. I mean the psychological influences of, I mean if you just ate, well, one single kind of food all the time, it would get pretty boring and astronauts will be the first to tell you that some variety in their menu and their diet is a highly desirable thing, not only from the nutritional aspect, but from the psychological aspect as well. It just feels better. And choosing the plants is not really as difficult as it might sound.

They are exactly the kinds of plants that you would consider being incorporated into a normal vegetarian diet because, of course, the first visitors to Mars will have to be vegetarians because we're not taking any animal food with us or at least not much, other than what we can pack away. And so those crops are just those that you would normally consider: rice, wheat, potatoes, sweet potatoes, peas, beans, corn, lettuce, tomatoes, peppers. It's what you would find in your average grocery store produce section.

John: This is a good question to follow this. How big would a Mars dome have to be to sustain a small exploration crew of four to six people?

Mike: That's an excellent question. That is one of the main numbers that we are chasing and at the moment, and obviously we're trying to make that number as small as possible because the less space you need to grow plants, then the more economical and the more technically feasible it is to actually get that system up into space and on to the planet Mars and functioning. At the moment, the estimate for the area required to support a single person indefinitely is approximately 36 or 37 square meters. Now that is based on a lot of crude estimates in some cases and very precise estimates in others.

But most of, in fact, all of the research around advance life support in application of plants is designed to bring that number down in one way or another so that we can get less and less space devoted to the food requirements of the individual. So a crew of four people, for example, would need as much as about 115 to 120 square meters of plant growing area to sustain the range of different crops in order to get the variety and the range of crops to give you the nutritional requirements to supply all of the food requirements.

John: Another question here from Patty. Will plants go up as huge or small plants? If small plants, how will they survive a launch?

Mike: For very short-term experiments, in fact, there's in seven days a shuttle is launching and there will be some plants, I believe wheat plants are going up on the Pesto experiment. Mixing up my acronyms here. But the Pesto experiment is going up, so they will be going up as seedlings and they seem to survive that reasonably well. But for really long term missions, obviously, seeds are the most economical way to transport things and we'll use packages of seeds and then, of course, for really, really long term then the plants will recycle and grow pretty much their own seeds.

John: One more question before we break for that video clip. How big will the plants be when you take them to Mars? That's exactly what you were talking about.

Mike: Yeah. It depends on how we end up using plants on that transit mission. It's unlikely that plants will be the sole source of life support on the transit mission because we simply don't have enough space on the craft that will go to Mars to grow that many plants and support a crew of six, for example. You'd have to tow along a heck of a big greenhouse to maintain the life support requirements.

So there will probably be bags of seeds that will go to Mars and we may even deploy them before astronauts even land on Mars. We may even have automated systems that would plant a few seeds in automated greenhouse structures that would be set up on Mars by robotic missions. But this, again, is all speculation. These are all these brainstorming ideas at the moment.

John: Let's break to our video clip with Yuli Berkovich. Once again, he will be talking about his research at Kennedy Space Center and in Russia. I would like to prepare you for this video clip by saying his primary goal in Russia is to develop a greenhouse, which could continuously supply the crews of the ISS with leafy green vegetables. And here at Kennedy Space Center his project is to develop an artificial soil made from a resin and to also build an automatic watering system that will supply the roots with enough nutrients to keep the plant healthy. Okay. I hope you enjoy the clip.

Yuli: My name is Yuli Berkovich. I'm a Russian scientist here at the Kennedy Space Center for one year [inaudible phrase] in space.

I would like to show you our last design [inaudible phrase].

You can see the [inaudible phrase].[inaudible sentences to follow] (too much background noise - makes speaker inaudible)

And now I will just show you what I'm doing here in the Kennedy Space Center now. My main job in Kennedy Space Center is to [develop new plant delivery] for [inaudible]. This system should contain new artificial [inaudible] [inaudible] for plant growth. And also, the system for [inaudible phrase] for maintaining appropriate, to create moist [inaudible phrase]. [inaudible phrase] moisture inside the chambers. Let us look at these plants right now.

Now we can see much greener plants inside the chamber. The plants are growing under the [inaudible phrase].

In conclusion, I would like to [inaudible phrase] research and for advanced growth and [inaudible phrase] thank Kennedy Space Center for the opportunity [inaudible phrase]. And also I would like to thank my colleague from this [inaudible phrase]. I believe this is a good way to study [inaudible phrase].

John: Okay. I'd like to thank Yuli for taking the time out of his schedule to help us out with today's Webcast. Once again, if you have any questions for Yuli about his research, we are having a follow up chat on the 8^th at 1:00PM Eastern Standard Time and 10:00AM Pacific. For updates on this chat, go to the calendar page.

As Yuli demonstrated, his Chinese cabbage grew very efficiently. What else can plants do besides provide salads for the ISS crew?

Mike: Well, we've been talking a lot about this advanced life support and the application of plants, the contributions that plants make to life support and food is the main driving variable, but plants in space will provide us with food. The photosynthesis consumes carbon dioxide that we breathe out. It also generates oxygen, which we need for our respiration and plants recycle fresh water.

So the source of potable water or water supply daily will come from the recycling that plants do. So they're sort of a machine that does all of these life support things for us. And in the near term, the application of plants on the International Space Station will be mainly for, and here at Kennedy they're talking about this technology and they're calling it the salad machine. The salad machine is just that.

It's a plant growing system to grow small plants like radishes and lettuce and spinach and things like that and cabbages for salads, not to provide all of those contributions to life support that we know plants can do and do so routinely. That's how this planet works. That's how we survive on this planet; it's the contribution that plants make to life support here.

And doing that in space is the challenge here, so on the Space Station we're likely to do it in a small scale way and the contribution that plants will make to life support on the Space Station will simply be in a little bit of an extra salad, a little taste sensation, certainly some psychological benefits of having some green living things there that you can munch on. But beyond that the contribution to total life support will be rather small.

John: Let's move right along here and talk a little about to finish things up, talk a little about long duration space missions. How much food and water will the astronauts need to bring with them on a trip to Mars, for instance? Will they need to bring or take, for instance?

Mike: The food requirement, I don't recall the numbers. I was just talking about the water requirement this morning with another of my colleagues and the water requirement is estimated to be around 27 liters a day per person.

And so that's the requirement to recycle fresh water. It turns out that plants, certain plants and certainly the plants that we'll be using can recycle lots more than that. A square meter of plants can recycle as much as I think it's in the neighborhood of 10 or 15 liters of water per day depending on the energy source and the light levels and the temperatures and a whole lot of other environment variables.

But suffice to say that plants, especially the size of plant community that we would require for the food production, would generate far more water than we need, would recycle far more water than humans alone need and certainly produce more oxygen. We'd have oxygen to sell to the Martians if we ever found some and the carbon dioxide consumption potential of the food growing area would certainly be in excess of what we need to use up the C0₂ that we breathe out. So the life support contribution is currently being driven by the food production requirement. And all of our research is designed to scale that down as much as possible.

John: Right. Once they are on Mars, they'll have to wait a while before they can come back, so we'll have to have food on Mars.

Mike: That's true, right. The classic you can't be there from here thing. There's a 26-month window for going to Mars, so you leave Earth and you fly out to Mars and it takes you about six months or so depending on what time of the year or the decade it happens to be. And then when you get there, you literally can't get back. There's another 20 months after you get there before the return window opens up again.

So once you get to Mars you're stuck for a good year and a half or so. And then, of course, there's the six months or so for the trip back. So we're talking about, in general, roughly a thousand day mission necessitated by the fact that you can't get home once you get there until another year and a half or so goes by when Mars and the Earth are physically close enough for you to actually blast off of Mars and get back.

John: Here's actually a picture, an artist's rendition of life on Mars.

Mike: And that's the plant growth facility there and at least the concept of what kind of technology will be required to grow plants and maintain atmosphere and water recycling on that planet.

Here's another artist's concept of a whole series of little Mars domes or based on that kind of concept and these are pretending to take advantage of natural lighting conditions on Mars. Of course, that depends on whether the radiation environment, whether the plants don't mind the radiation environment. So there's still quite a few questions and there's still quite a few numbers that robotic missions to Mars will bring back to us plant scientists to help us design the systems that will be best deployed on that planet.

John: At this time I will finish up with the chat room. Let's go off and do that. Let's knock this question out here from Sylvia.

Mike: She's wondering about Mars terra forming and that means turning Mars into a planet something like Earth with plants and water and all that sort of stuff. Now she's aspiring to be a Mars agricultural manager engineer and there's certainly lots of room for that kind of technical expertise in the programs both here at Kennedy and in Canada and across the states in Johnson and Ames Research Centers.

But terra forming Mars, turning it into a place that is routinely habitable or visitable like by humans is a long, long ways off. It's certainly not in our short lifetime, but the technical challenge of contributing to that mission is certainly available to you today. So you can certainly get involved in the research and activities around the world. There are a number of agencies involved in advanced life support requirements and they are in Japan and the European Space Agency, the Russians, of course, and the Canadians and NASA form the five main contributors at the moment to that particular mission in advanced life support.

John: Here's another question. Where would the energy come from to power the lights for the plants when they are in the underground habitat?

Mike: I suspect that's a trick question. There are a number of technologies. Of course, the political sensitivity of deploying nuclear power stations on other planets has to be dealt with. Many scientists would simply love to be able to have a sort of very reliable and useful power supply like that.

However, there are lots of other technologies, alternative energy sources that are being investigated and a lot of energy is being put into fiber optic plumbing] of light from the surface down into an underground habitat. The Japanese a few years back had something called a sun blossom, which was a big array of fiber optic ends that collected solar radiation and piped it down into buildings and potentially underground and that is an application that is being looked at. Developing new supplementary and artificial light sources is also light emitting diodes. There are companies currently working for NASA and collaborating with NASA on developing new systems like that. So I'm quite comfortable in the technology development that we'll get there.

John: Here's another question. What sort of considerations are taken into effect during microgravity experiments with respect to a gravity well? Do you understand that?

Mike: No. Microgravity, as I said, is an issue that my group in particular, especially back in Canada, we're tending to step around because the technical challenges of dealing with not having gravity are just too hard and we'd like to be able to say this is up and this is down and then we can deal with all of the issues. And we're starting to learn that the technical challenges and the possible hazards of microgravity for humans in space are beyond us as well. So I'm hoping that the resourceful engineering community on this planet will come up with some artificial gravity even in lower orbit and then I don't have to deal with that question. Now that's political bias, of course.

John: I Understand. Now let's answer this next one, right? Now Washington Middle School. What are the odds of plants surviving?

Mike: The odds are very, very good. I mean we've already grown plants from seed to seed in space, so the odds are exceptionally good. We have the technology and basically it's fine-tuning it to make it work indefinitely as an element, as a machine for life support in space.

John: What plants grow best in microgravity?

Mike: I think any plant. Microgravity, once again, that whole issue of microgravity. I wish people would just forget about it. The microgravity challenge is one, in turns of long-term life support, microgravity will only really be in effect while on transit to some other place or when we're in lower orbit. Lower orbit is relatively easy to and economical to resupply. So the concept of having lots and lots of plants on the International Space Station as the sole source of life support, which goes to another question here earlier recorded on the chat room from Christopher, the International Space Station will almost certainly never rely solely on plants for life support because it is relatively easy, I shouldn't say that; it's not that easy. But it's relatively easy to resupply the International Space Station with peanut butter sandwiches and water and oxygen and things like that than it is to build a plant growing system, especially if you need 30 or 40 square meters per person. So that is unlikely to be the case on the International Space Station, so a big challenge of microgravity with lots of plants is, hopefully, not ever going to be a problem that we plant scientists will have to deal with.

John: Another question from Mountain View Middle School. Once they create a Mars garden, will they leave it there or bring it back to Earth?

Mike: Oh, they'll l certainly leave it there. There's no question that once it's on Mars, it's there to stay and there will be no such thing as garbage there. You can't waste anything. It costs too much to get it. Have to recycle everything.

John: Okay. I believe that's all the questions we have in the chat room for today, and in closing I'd like to thank Mike for taking the time out of his busy schedule and we really, really appreciate you coming in and joining us.

Mike: Any time. Thank you.

John: And I also would like to thank Sabina and Yuli for helping us with our video clips that you saw today. And, once again, go to their follow up chats on the 8^th and on the 10^th of April.

Finally, I would like to thank NASA Quest and Fundamental Biology and Kennedy Space Center as well. And most importantly I'd like to thank you, our viewer, for participating in today's Webcast. Once again, my name is John Rau. Have a good day.

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