Astronaut training for beginners
What would a trip into space feel like? To find out, Izzie Clarke spoke with Alec Stevenson, from QinetiQ, and she got put through a taster of astronaut training...
Alec - We're at the human centrifuge facility in Farnborough. At the moment it's the only human rated centrifuge we have. It’s a great big spinning arm, it's about 34ft in radius, or 60 ftt in diameter and it's been here since 1955. Primarily in the early days was to research the effects of these G forces on humans. More recently to train our fast jet pilots how to cope with the forces they experience when they maneuver in their aircraft, and we also do a bit of space research. In fact, we’ve done some training space tourism to the International Space Station, and now recently doing some research looking at the respiratory effects of high G forces.
Izzie - So basically, to put it very bluntly, it's a little pod on a massive metal arm. It gets spun around very very quickly
Alec - That in essence is what it is yeah.
Izzie - Now I can just see our first victim has climbed into the centrifuge. Tell me, what actually happens once this giant arm starts to spin?
Alec - The arm takes a bit to start going, it’ll idle around the room a bit and then the motor will kick in. And how we’ve set it at the moment, it will accelerate at 1G per second. If we go to 3G it will take two seconds to get up there, so very quick, and then sustains that level for how long you want. For today, I think we'll just keep it to 15 seconds. Now what the person in the pod feels is that there is a sudden increase in their weight. So moving their hands and arms around is much more difficult. Also because their weight their blood has increased it will tend to head downwards. What they might experience depends on how low the blood pressure drops as a loss of vision and that's caused because the eye has actually got internal pressure to hold it in that spherical shape, and it's harder for blood to get back into that eye. You lose your vision first and once you've lose lost your vision that's when you end up not going enough blood to the brain and therefore and then you end up losing consciousness but hopefully we won't get that today. We'll just see a bit of visual loss which is very dramatic and easy to see.
Izzie - Does this mean we can have can have a go?
Alec - You can indeed have a go.
Izzie - Oh my goodness, I better go and suit up!
Okay. So I didn't actually have to wear a spacesuit which was rather disappointing. I climbed into the small pod ready for a spin.
ENGINEER - Isabel? Hi, can you hear us?
Izzie - Yup.
ENGINEER - Hello, control? If you’d like to set us up for 2.4G run. We'll take that as our first taster for 15 seconds. Then if you happen at 2.4 we can take you up a few steps beyond that.
Izzie - Perfect
CONTROL - Two point four for 15 seconds. Stand by…
Izzie - Here we go!
Initially, I’m sat upright but as the pod accelerates around the circular room, I’m tilted sideways. The top of my head pointing towards the centre. This causes the blood to rush down towards my feet, much like a pilot would experience in flight/
Engineer - And you can talk to us?
Izzie - YEAH! It’s okay. I was expecting it to be quite intense but it feels like a giant rollercoaster.
...In fact by my fifth run. We took it to a maximum for a newbie like me. Up to 4.2G. And yup, my vision disappeared. Tensing legs and stomach muscles you force the blood back up towards your head and suddenly your vision clears. Hopefully. Whilst I recovered from the motion sickness, Alec explained why it's important to run these practices.
Alec - There’s a medical thing. We need to check that the actual forces that were subjected are pilots and astronauts to don’t cause them any physical harm. There's a familiarisation piece as well, because it's an unusual sensation that they wouldn't normally expect to have in life. Particularly for astronauts, those sorts of accelerations are just really for space although it's not necessarily for that kind of acceleration, that Chest-to-back acceleration, training per say we can do. It's the sensation that there need to be familiarized with so that they can get on with what they should be doing - concentrate on the task they may have to do in the spacecraft. As you were about 4G, we should be able to get you up to 9G with the kit that we've got and some training.
Izzie - I don’t think I’m quite ready for that. The sensation in your body is so strange. Everything feels a lot heavier as astronauts take off their lung feels so heavy. Does that have any health implications. How can we even study that?
Alec - It does have health implications, it does affect how your lung works and obviously a lung is very important. It's how we get option into our blood. So one of the things we can, we can measure how that acceleration affects the amount of auction you get in the blood and we've probably all seen a lot of clinical programs where we've seen a little clip that you get on your finger, it's called a pulse oximeter, which measures that percentage of oxygen that's the hemoglobin saturated with.
We can do that and we can see that that is markedly reduced when we are under that sort of acceleration. The good news is, when we turn the acceleration off that tends to return to normal. As the lung as quite spongy, it distorts under its increased weight. What you end up doing is stretching the top parts of the lung, the top the parts are at the chest, and the bottom parts of the lung which are in your back, they get compressed. There is an element of that when we're just lying on our back. But because it's only 1G, there's only a slight difference between the top on the back and as we increase the levels of G that just amplify that difference.
So we're concerned, I suppose under GX, that we get a part the lung at the base that's gone under so much pressure that it cannot actually closes off and doesn't communicate with the atmosphere, because it can’t get air into and out of the lung, the blood that flows through it just doesn't pick up any oxygen. It contributes to what we call a pulmonary shunt, a proportion of the blood that were pumping out of a heart that doesn't actually pick up oxygen. It runs through the lung and obviously that mixes with bits that do pick up oxygen and just lowers the average saturation we've got.
Now the issue with the top part of the lung is that it gradually gets stretched and stretched, and like any mechanical component, will eventually cause damage if you stretch it too much. A lot of the stuff that we’ve done suggests that the levels we're doing are safe. But there is a degree of stretching there. We need to be careful that if we've got some individuals who already have issues with that lung that if we stretch any further are we actually then going to cause an issue, a tear or something like that. So it’s something we need to consider.