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Animals in space!

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Matt Smith:

Space, the final frontier, humans have a proud tradition of sending animals into space. Starting with mayflies in the 1940s and progressing to dogs, monkeys and mice, they've been used to study how humans would respond and develop in a weightless environment. I'm Matt Smith and you are listening to a La Trobe University podcast and this [Frog croaking] is a frog [Frog croaking].

If I wanted to know how it would respond to being in space, I'd have to build a rocket. Unfortunately, the most we can manage is this. Here you go little guy [Frog croaking]. He'll come back eventually, but while we're waiting for him to come back let's talk to somebody who's done the work for us.

Richard Wassersug is a professor of anatomy and neurobiology at Dalhousie University in Halifax, Nova Scotia. He's been studying frogs and tadpoles for years.

Richard Wassersug:

One of the most remarkable phone calls that I ever had, a message left in my desk, this goes back like 20 years ago, and I came back to my office one day and there's a message that said, frogs in space and call so and so at NASA. And here I am a scientist in Nova Scotia, Canada supposed to call some official I've never heard of at NASA. Well, it turns out that led to like essentially 20 years of work on how animals behave in weightlessness. This is back in the late 1980s, NASA had been designing and building a very elaborate experiment to look at how the absence of gravity affects the development in frogs.

The reason for working with frogs is the development is external, you can actually watch it happen. You couldn't do that if you're dealing with a mammal where the embryo is raised inside the mother. And it turns out that they had built this fabulous flying incubator and all of that but the experiment turns out on a mission that was going to be longer than just the embryonic period. And when the space shuttle -- this was designed to fly in a space shuttle -- came back that we're going to have tadpoles and they looked around for somebody who's been studying tadpoles.

With that point I've been studying tadpoles for about 20 years. I was invited in to be part of this study. It was quite an exciting time in my life. I was very flattered. We flew the frogs in space, the frogs were bred up there, and the tadpoles came back and then my part of the experiment kicked in when we had to decide whether they were normal or not. And I had feared that they will not have normal lungs. Even though we think that it was aquatic and becoming air-breathing when they become frogs, most of tadpoles actually start air-breathing as tadpoles and they have to come up to the surface to take a bite of air.

If you think about that there is no up in space. It's an interesting concept, up is the opposite direction away from the gravitational body that is pulling you down and if there’s no gravitational body pulling you down if you're not falling. There's no option to oppose it. So it wasn't clear that the tadpoles have nowhere to go to get air. And indeed, it turns out that they were not normal in terms of having not developed their lungs at the right time.

That led to a whole variety of other experiments looking at not just those tadpoles but looking at the ones who were a little later that actually went through the hatching process in space and those were the ones who were most disturbed by not filling their lungs but they could correct for it if they got back to Earth early enough, they could still correct for it.

They didn't get back to Earth early enough and they were deformed and they were in trouble. This led to looking at other animals. Since then Japanese have raised salamanders, fish have been bred in space and so forth. No mammals have actually been bred in space but I've been privileged because I've actually published on several experiments, I’ve flown in the space shuttle, I published on animals that have been on the Mir space station. And before you send an animal up in an orbiting platform like up to the space station, what you want to do is see how it responds just for a few seconds on weightlessness. So I started doing some parabolic flights and these are airplane flights that accelerate upward, arch over and spends up to 30 seconds in free fall which then gives you a sense of weightlessness within the frame of the plane. And that led to a whole slew of experiments looking at behaviour of animals in weightlessness.

And they don't all do the same thing. They do very remarkably different things. Some roll, some get in all sorts of contortive postures and that has some implications to what animals you might want to design for space flights. Some animals can handle weightlessness and aren’t stressed by it, that's very different and if animals totally freak out and exhaust themselves trying to grasp with anything to keep from falling. I’ve become something like an expert on bizarre things that animals do in weightlessness. I have a fair bit of video footage of this as well.

One particular thing that's interesting is that humans get very nauseous exposed to weightlessness. When you think about someone going on a rollercoaster ride and getting nauseous and vomiting at the end of it but these parabolic flights are 10,000 or more feet rollercoaster rides so they are really provocative, they stimulate vomiting. And we used to look at vomiting in the animals as well. And it turns out that the animals had spin, and twist and most in space, other ones are going to get most nauseous. And most amphibians and reptiles are immune to it, which is also very interesting.

Matt Smith:

Let's go back to the frogs and tadpoles in space. I'm assuming then that tadpoles and frogs aren't suited to be in space. If a frog develops from a tadpole up in space and it's really not going to survive very long if its lungs hasn't developed.

Richard Wassersug:

Well, it's certainly not going to develop normally. If they come back at very early stage they can correct for this and avoid -- well, ultimate abnormalities but if they're up there lone enough, their lungs will solidify and they will have a real hard time. Their tails get distorted and they also have some organ system problems associated probably with respiratory complications. And this has implications for long-term space flights for our species. It's quite remarkable and it's a sad story, actually, that we've been in space now, we've had animals in space for over 50 years and we still haven't raised a single mammal through a complete lifecycle in space.

Matt Smith:

Has it been tried?

Richard Wassersug:

The Russians did a very bit of experiments where they tried to look at early embryonic genesis with rats but the facilities to raise, say, rats, a small mammal in space don't exist. Mir space station no longer exists, the international space station was supposed to have those facilities on it, it doesn't.

It's now seen as obsolete even though they didn't really finish it. They already declared it obsolete, so we're way behind. If you look at what's happened in other scientific fields; molecular biology, genetics, in the last 50 years neurobiology, look at those fields, they've exploded with information.

The space biology has been greatly hampered by the inability to actually get up into space in a safe way. It's very dangerous and very expensive to get things into space and space biology is faltering. We really still don't know how long it's safe. We can set up adults -- humans, for over a year and they can -- they'll come back and can recover from it but if we're going to look at long-term missions such as to Mars, we might want to ask whether humans could safely breathe in space and we don't know whether they can or not.

Matt Smith:

Because if you take on a trip that long I assume there has to be some sort of ark that went.

Richard Wassersug:

There will be an ark if you're going to talk about a trip to Mars and back but certainly, we don't know all of the ways that the absence of gravity can affect development. For frog's eggs, going back to them, here on Earth they are actually affected by gravity.

When the egg is fertilized, it has a denser and therefore heavier side and a lighter less dense side and they rotates it with the heavier side down and the way the cells divide from thereon to two to four to eight and so forth is oriented towards gravity. It turns out that in space that doesn't happen because there's no gravity but they're not bothered by that. What happens is that this later organ development that is serious one might imagine this could affect humans.

When you and I -- if we were in weightlessness, we will find that our lung volume would go down because our livers will float higher up lower our lungs and push our lungs up. We can correct for that and we know that for astronauts they actually have a change in respiratory volume and they come back. But what if you are developing in space and your liver always floated higher, you might have a permanent problem with your organ development.

So really this isn't mystical and complicated. It still looks like that we may have problems with organ development, the difference is you're a person doing the growing phase is in space, certainly we would with the bones.

We know that bones need to be loaded with weight in order to grow normally. So space is a dangerous environment based on little that we know about it at this time. We've been there 50 years and we still know very little.

Matt Smith:

You said that you've studied a number of different animals in weightless environments. What animal or what characteristics that animals have cope best in that sort of environment?

Richard Wassersug:

That's a wonderful question and it turns out, if I can back to the frogs that I've worked on, basically you have two types of behaviours that frogs can do. In weightlessness, most frog and toad-like animals interpret free fall as if they're upside down. It turns out in our invertebrate years, be it frogs or humans, there are little mineral deposits that sit on the membrane that sits on sensory cells. And that tells the animal which way is down. If the animal is in free falling is weightlessness, those mineral deposits float off that membrane. If the animal is upside down they're certainly off the membrane. So a lot of animals interpret weightlessness as if they're upside down and they try to correct that and roll over.

They’re weightlessness again, they're not going to get any feedback that they've done, so then stops spinning. This can be rabbits. They could be turtles trying to roll over if they can do. They can be lizards and so forth. But there's also another response to weightlessness and that is on arboreal animals which jump from branch to branch and tree to tree and they're designed to live in free fall, they make use of free fall.

And what happens if you have two frogs that are quite similar, one is a ground frog and one is a tree frog, and the tree frog spread their arms out and hold them in a lateral position, legs as well -- and when I give lectures of this I ask people what is this posture and usually if there's an audience of 30 or more people there, someone recognizes it as a skydiving posture. It's exactly the same posture we take when we try to be in free fall and control the fall.

And so we have animals that are adapted to doing that. But those animals don't get sick in weightlessness provided they don't spin. So this is an example of where these type of studies which sound like a lot of fun and they are. But it actually has some relevance to try to pick the right animals for space flight experiments. And by the way, the story I just told you about frogs applies -- it's the same way with lizards as well. So you have arboreal lizards that like to skydive and you have ground lizards that spin wildly trying to roll over and to find the bottom where there isn’t one. Very different behaviours from animals that looked very similar.

Matt Smith:

That's all the time we've got for the La Trobe University podcast today. If you have any questions, comments, or feedback, you can send us an email at podcast@latrobe.edu.au. Dr. Richard Wassersug, thank you for your time.

Richard Wassersug:

You're welcome, thank you very much.