Eye balls in, eyeballs out.
The familiar forces we know on earth change if we move out into space. Astronauts must be trained to meet these new forces. Here is part of a training programme in which astronauts learn to cope with the forces they will encounter during blast off and re-entry into the earth’s atmosphere. (line 4)
The centrifuge was the most spectacular of the machines we used in training. We called it the wheel. It was a pill shaped cabin 2 metres by 3 metres, suspended at the end of a 15 metre arm. We were whirled around in it at enormous speeds to simulate the forces of acceleration we would experience during space flight. (line 8)
Acceleration takes place when a moving object increases speed, or changes direction. You will have felt this force on a fast roundabout or roller coaster at, say Oakwood. You feel your body being pushed away from the direction of the turn. If the speed of the car is great enough you may even feel as if a weight were pushing you against the side of the car. Magnified many times that is the sensation an astronaut feels when the spacecraft is lifting him up. (line 14)
On a usual run we would climb into the cabin with our helmets on, and on a very tough test we would wear a full pressure suit. The technicians would strap us into the moulded couch. The cabin was turned so we faced towards the centre of the wheel. This let the acceleration forces shove us into the couch just as we would be pushed back by the acceleration at blast off. During these tests it felt as though our eyeballs were being pushed right back into their sockets. We called this kind of riding “Eyeballs in”. (line 20)
We also did runs to imitate the slowing down forces of deceleration. On these occasions the cabin was turned so that we faced outwards. Then we would feel pushed from the back, the forces tending to throw us out of the couch against the restraining harness, instead of pinning us in. Then it felt as though our eyes were popping out of their sockets. These were the “Eyeballs out” runs. (line 25)
On a usual run the centrifuge starts up slowly and the forces build up slowly. Even so the pressure almost immediately forced us back against the couch. At top speed it felt as though we were 8 times heavier than usual, which means it felt as though there were 8 people pushing us back down into the couch. The force on our chest cavity was then so great that we had to work quite hard to breathe. Some of us found it easier to breathe if we grunted the air out. I found it better to hold my breath, let it all go, and then hold it once more. (line 30)
We also had to strain all the muscles in our legs and arms to keep the blood flowing away from the abdomen. Under the action of the high forces, it tended to collect there. We used our muscles to push it back to the heart. If we relaxed the blood began to drain away from our brains. Then our sight began to blur in a sort of “grey out”. This is the first step towards unconsciousness. But if there was any sign of this sort of trouble Bill Douglas, our flight surgeon, would switch off the machine and we would be brought back to a fast safe stop.
Answer the following questions in complete sentences:
1)At which parts of a space flight would astronauts feel the greatest forces? (line 3)
2)In which direction did the training machine move? (line 7)
3)What is meant by the word acceleration? (line 9)
4)What is deceleration? (line 21)
5)What is the name of this training machine? (line 26)
6)How many times heavier on a usual run, did the astronauts feel? (line 28)
7)How did astronauts keep blood from flowing away from their abdomens? (line 31)