Helen Sharman: science experiments in space

Chris - In that moment, when the acceleration stops, the G-force fell away, and you realised that you were floating. That must also be pretty elating.

Helen - First, when the final rocket engine is jettisoned, you're right, that's when we do feel weightless, but we're still strapped into our seats. So it takes another two and a half hours before we've checked that everything is safe enough for us to unstrap and take off our spacesuits. Obviously, I was feeling weightless. My body was responding to feeling weightless.

I was no longer sitting down in the back of my seat. Although I was strapped in, I could sometimes feel a bit of a gap between the back of my seat and me, which is very nice because it was very hot in those spacesuits - quite a lot of sweat. And so I could sometimes feel that the ventilation was actually going behind my back and cooling me off a bit. That felt nice. But yes, it was a while until you could really unstrap and float out, but even then the spacecraft is quite small. But it was enough to do a little, tiny tumble, and be able to pull yourself through and just stretch out a little bit. The weird thing is our actual bodies - and again, this is part of the training - but never actually having felt it before. Body fluids, it's what you experience first, really, they tend to migrate more towards the upper chest and head because they're no longer being pulled down towards our feet by gravity.

And it takes a while for our bodies to properly adapt and get rid of what we see as too much fluid in our brains. If you ever see a photograph of an astronaut and they've all looked fat and puffy faced, you know that they've not long been in space. It takes about two or three days for you to get rid of this extra fluid. Some of it does come out as additional urine in the toilet and sometimes it's just then redistributed throughout the body, but you feel as though you've got this pressure. Your nose is a bit more congested. It's one of the reasons why we don't want to take colds into space as well. That would be really unpleasant.

Chris - People also talk about visual changes and people's retinas change shape a bit, don't they? Did that happen to you? Did you have any visual changes?

Helen - My retina must have changed shape. The pressure in the eye must have pushed it back a bit, given me a bit more of a high pressure eyeball - a bit like glaucoma does for people sometimes. But I didn't notice any particular visual changes, perhaps being quite young - I was in my late twenties - maybe my eye was still quite accommodating then. But we do know that it tends to happen. Although it may happen to most astronauts, most astronauts come back to Earth and then the eye at least reverts to what seems to be a semblance of what it was before. For some people it doesn't. And so some astronauts then wear glasses for the rest of their lives. I now wear glasses, but that's just because I'm getting older! But, no, I don't think I really had any visual changes that were noticeable to me in space and back on earth. There was nothing permanent.

Chris - What were the experiments you were doing? You mentioned that you were doing a mixture of some UK experiments, but a lot of Russian experiments. What sorts of things did you have to do?

Helen - Yeah, the UK ones were mostly based around what school students had suggested. So they were my sort of spare time experiments. The Soviet experiments were, for me, a lovely variety. I've always liked variety. And so to be able to do stuff as a chemist, like growing protein crystals, is absolutely amazing. So I grew luciferase, which is a protein that we often use as scientists to attach to other proteins. And when it glows, perhaps in the presence of ultraviolet light, then we can see the presence of the molecule that's really of interest. But yes, just growing protein crystals, you can't grow them very big on Earth, and those that we can grow on Earth tend to have got lots of broken bits, dislocations we call them, between the molecules within that crystal. But you can grow protein crystals bigger and much more beautifully formed in space. So the molecules are just positioned right around each other. By doing that, we can then bring some of these crystals back to earth. And the knowledge that we can gain by doing that, the idea is that we design drugs for treatment of certain diseases on Earth. In fact, recently, we've got a treatment for Duchenne muscular dystrophy, which can significantly reduce the progress of that. And that's been because of a protein associated with that disease that was grown as a crystal in space. So as a chemist, to get crystals, protein crystals: fantastic!

It got really interesting to see how plants grow. The roots grow in weird directions in a strong magnetic field. You can force roots to grow in a particular direction in space. Sometimes plants have a hormone and so those roots will grow against the direction of the light. So of course the green leaves will point towards the light, you still get that, but to be able to look at how plants grow with a view to long-term space flight, as well as growing them on Earth. And again, these experiments have really come on in leaps and bounds in the last few decades.

I think probably the most surprising experiment to me was one that felt the most boring at the time. I had a whole frame, I had to put a load of different films of ceramic in. There were different ceramics and the idea was to investigate future spacecraft exteriors. And for me that was a fairly dull experiment. But I did have to use the airlock and, having never experienced a space walk, using the airlock was my nearest bit to going out into space. So I got all these parts in the frame and got them in the airlock, and then closed the airlock on the inside, exposed it to outer space at the radiation, the vacuum. And then, after a couple of days, brought them back into the space station. And all I really had to do was then bung them into a machine that would look at the surface and how they'd been degraded perhaps and then give the results back to the scientists. But when I brought these back into the space station, there was a smell and it was the first time I had smelled anything since I arrived on the space station because, of course, you don't get a window that opens and gives you a fresh smell. We're sitting here on the banks of the Cam and I can smell the river. I couldn't smell that in space. I couldn't smell grass, I couldn't smell air. You just have this very... well, your brain doesn't register it anymore, what smells there are up there.

So, I brought this thing back in and immediately my science brain said - because it smelled like metal - and I thought it must be the bare metal because the oxide layer must be stripped off by going into the vacuum. Made sense to me. But oh no, absolutely not. I've discovered subsequently that it's the radiation on the surface. In fact, whatever you put outside the space station smells similarly of this metal, a bit like ozone. If you have a spacesuit going outside, you bring your spacesuit back in, it smells the same. And so radiation just strips some of the bits of the molecules away. So we get these highly reactive free radicals on the surface of this material. And it's that that gives you this smell of ozone or bare metal. But it was the first time I'd smelled anything in space.

Chris - Amazing to smell space. Did you spend a lot of time gazing out of the window or did you struggle not to?

Helen - I'd been advised before I flew by an astronaut, one who'd only flown once. He said one of his biggest regrets was not having looked out of the window enough. So he said 'You'll be so keen to make sure you do a good job, wanting to repeat the experiments and communicate with mission control etc., but don't forget, take that experience!' And so I determined to take his advice and I'm so glad I did. It's just a magical view. And I think even the astronauts that had been up there for six months still enjoyed looking out at the end of a working day.

That's what we would do. We'd find the biggest window we could. It was actually a bit naughty because it was about a 40 centimetre diameter window, but it was sapphire. Now sapphire, rather than borosilicate glass or something, means you can get all the ultraviolet through it so that if you want to take some good ultraviolet pictures of the earth with ultraviolet cameras, then you can do that. Lovely. But, of course, it just means that you can get a bit sunburnt if you're not careful. It's also very, very precious. So it had a hatch on the outside, partly to keep it safe, but also to stop it from getting hit by bits of space debris and micro meteorites and so on. So anyway, we would open this hatch because it was big enough for all five of us to gather around. You can imagine our heads all pointing towards the middle of this circular window.

And we would just look out, talk about our families and friends as we passed over parts of the Earth where we knew people, and just really enjoy the view. Not just of Earth as well, actually. If this space station happened to be pointing the other way at the time, you can look at space and those stars and that is, for me, the most awesome sight. We have this rather American word, awesome, but really if anything's awesome, it is that view of stars from space. You don't have the atmosphere to filter out some of the light. So just stars absolutely everywhere. Gorgeous.