Kat - Now you may think when you watch something like Star Trek, they're all zipping around space in their little space ships and it's all fine travelling to other dimensions - all that. But the reality is very different and space travel has a lot of effects on our bodies. To tell us more about this is Kevin Fong and he's a space physiologist based at University College London. So Kevin, What sort of things actually happen to our bodies when we're travelling in space?
Kevin - It's much more of an insult to the body than people ordinarily think. Going into space is an expedition like any expedition, going to Everest and then to the South Pole. The two things about space are really radiation and the absence of gravitational loading (microgravity). Because of that your bones waste, your muscles waste, your heart - which is essentially a muscle pump itself - undergoes atrophy. You have problems with your balance and coordination. About 7 out of 10 astronauts spend the first couple of days feeling like they want to throw up. It's not pleasant and you genuinely come back feeling like you've come through a pretty tough expedition at the end.
Kat - Are there any things that astronauts can do to kind of get over this? What sort of things do they do at the moment?
Kevin - They partially solve the problem of the wasting of muscle and bone and the deconditioning of your cardio and vascular system by simply doing exercise.
Kat - They have little treadmills in space?
Kevin - They have treadmills that they strap themselves to with little bungee cords. They do that for a couple of hours - two or three hours - a day on most space station missions. That provides some partial protection. It doesn't do anything for your inner ear or your sense of balance and coordination. It only partially protects you from the effects I just mentioned.
Kat - You mentioned radiation as well. How much of a problem is that?
Kevin - In most of our current missions - the stuff that happens on space shuttle and International Space Station it's not that big of a problem, mainly because that all occurs well within the protective limits of the magnetic field. So far we've had astronauts for the longest mission of 438 days without any sever side-effects from that. I think in the future with longer missions going to the moon, going to Mars, to wherever it may be more of a problem.
Kat - At the moment the limiting factor on space travel really is how our bodies can cope with it rather than the technology, do you think?
Kevin - Very much so. That's the thing about human exploration of space. Humans are, by far and away, the most versatile and adaptable research tools that we have today. That's why we do so much exploring with humans on the Earth. They're also the most fragile link in the chain. Yeah, human biology is really the thing that makes it difficult. We've been throwing stuff at Mars and hitting it well - one in every three times since about the mid 1970s. The thing that's stopped us doing it with people is human biology.
Kat - Do you think if we're going to go on super long trips in space, the stuff of sci-fi, would we have to have babies in space? Do you think that's possible?
Kevin - Haha, well the longest missions that are on the chart at the moment look out at something like the mid 2030s and they talk about going to Mars and having human research out there. There's also a couple of things that also sound pretty sci-fi like putting people onto asteroids which is easier than you would ordinarily imagine.
Kat - Doesn't sound easy to me!
Kevin - In the far flung future given the laws of physics as we know them going beyond our solar system and further, then you're talking about needing to have some sort of sci-fi space colony. That's kind of beyond any immediate technology horizon as far as I can see.
Chris - I was just wondering about body clocks and things because when an astronaut goes into space they're obviously orbiting the Earth faster than the Earth is turning. What does that do to their body clock? Because we normally rely on the Sun and the night to set our body clocks so we don't get jetlagged.
Kevin - That's quite right. Circadian rhythms are really quite affected. My very good friend Dan Tanni is on expedition 16 which is flying at the moment and in the days just before he launched we were talking to him. First of all, they have to shift them. Space station runs on GMT so they have to shift them to the day of the launch so they're actually waking up and going to sleep at the right time. You don't want to have a crew who'd just be flying at 17,000 miles an hour into lower Earth orbit feeling a bit sleepy if it's the wrong side of the day. Once they get up there they get 90 minute light/dark cycles. They see the Sun come up and go down over 90 minutes. It does mess with their sleep patterns. There are many things that tell your body when it should be awake and go to sleep. These things are called zeitgeibers which literally means time givers. These things include when you're eating, what temperature it is. But the most potent one is light and dark itself. On the space shuttle and Space Station that's happening very, very rapidly. This basically boils down to the result that astronauts take tranquilisers like they're going out of fashion. They need a lot of help going to sleep.
Chris - Sounds like journalists and people who present radio programs to me! Wrong hemisphere to me.