Weekend
Spotlight:
Astronaut Training
Camp
Some of the Science behind the activities
 Equilibrium Training
Astronauts aboard an orbiting space station are weightless. This means that they have a continuous feeling of falling and all sensation of vertical and horizontal is gone. Weightlessness can be seriously disorienting to new astronauts, and they require a short adjustment period to get used to it when they first arrive in space. On earth, the experience of weightlessness can be reproduced only for brief moments such as when jumping off a diving board or while sky diving. There is not enough time to examine in detail the feeling of disorientation that the weightlessness produces.
Equilibrium training at Astronaut Training Camp is designed to use various methods other than weightlessness to deprive you of your sense of vertical and horizontal so that you can experience the feeling of disorientation for yourself. If the equilibrium training sessions are successful then you will learn to maintain your orientation in spite of the loss of some cues to the vertical and horizontal directions.
Planetary Training
How much do you weigh on other planets? The answer can be calculated if you know both your weight on Earth and the strength of the gravitational field on the other planet. The strength of a gravitational field is measured as the rate at which a dropped object picks up speed; i.e. –
it's an acceleration, sometimes called the acceleration of gravity. An object dropped close to the surface of the Earth picks up speed at the rate of 32 ft/sec for every second that it is falling. We say that the strength of the gravitational field at the surface of the Earth is 32 ft/sec2. The gravitational field at the surface of any astronomical body depends upon the mass of that body and the distance of its surface from its center; i.e. – its radius. The acceleration of gravity on the surface of the moon is only 5.3 ft/sec2, which is one sixth that on the surface of the Earth. Thus, on the surface of the moon you would weigh one sixth of what you weigh on the surface of the Earth.
Today's training consists of determining the weight of an object on other planets from its weight on Earth and the gravitational field strength on these other planets. You also will be able to pick up and handle a series of small, identically appearing suitcases that have weights matching the weight of the suitcase labeled
"Earth" if it were placed on another planet.
Space Environment Training
Most of us know that there is no air in space and that space travelers must bring air with them in order to survive. Astronauts and cosmonauts living inside a spacecraft such as the International Space Station
don't need to wear space suits because the space station cabin, like a balloon, is filled with air. If the space travelers go outside their spacecraft they must wear a space suit at all times, which provides air for them to breathe AND atmospheric pressure for their bodies. A space suit is really a body-shaped balloon filled with air. It provides breathable air and atmospheric pressure over the entire body. We all understand why air for breathing is necessary for survival, but what about atmospheric pressure? Why is atmospheric pressure needed?
Imagine an astronaut who ventures outside his spacecraft with a SCUBA type breathing apparatus, but no space suit. Could an astronaut survive in space like this with all the air he needs for breathing but with no atmospheric pressure on his body? The answer is NO, at least not for more than a minute or so. Atmospheric pressure prevents our internal organs from hemorrhaging, our blood from boiling, and our air-filled lungs from bursting.
The vacuum of space is a harsh environment where air to breathe and atmospheric pressure to prevent us from hemorrhaging are absent. At Astronaut Training Camp we will place various objects within a vacuum and observe what happens to them.
Space Station Training
Living in space requires an adjustment to the conditions of space, which can be significantly different from living conditions on Earth. One must get used to the disorienting effect of weightlessness that gives the astronauts a continuous feeling of falling. Weightlessness forces major changes in the everyday aspects of our lives including activities such as eating, sleeping, working, washing, and using the toilet. In addition, we must learn to live with others inside a confined space and must bring with us all the resources required for living in space. These include air, food, water, recreation, and more.
Since space missions are becoming longer in duration (ISS – 5 months; round trip to Mars – several years), our required resources will become scarce in supply. We must learn to conserve them and to use them sparingly. It would not be good to run out of air on the way back from Mars. Air and water are recycled and reused on the ISS. Many types of foods are dehydrated to minimize storage space and prolong usability. Trips to Mars may be sufficiently long as to require that the astronauts grow some of their food in space.
Our training today will teach us how some of the everyday aspects of our lives are changed when we live in space. We know that we breathe in oxygen and exhale carbon dioxide. In a confined space such as a space vehicle, the carbon dioxide concentration in the air would increase and oxygen would become depleted. More oxygen from the resource supply must be added to the air and the carbon dioxide must be removed. Concentrated carbon dioxide in the air is a poison and would kill us even if the air also has sufficient oxygen. It is very important that the astronauts continuously monitor the carbon dioxide concentration in the air that they breathe.
Using a space toilet is another activity that is very different from the way it is done on Earth. Special training is required to use the space toilet correctly. In space, where everything is weightless and floats around, it is most important that you learn how to properly sit on the toilet and how to stay there until you flush it. Space toilets have no water in the bowl. Instead, the toilet is air-flushed by momentarily connecting it to a vacuum tank. A small amount of cabin air is then quickly drawn through the toilet to flush it. The wastes are collected in the tank and brought back to Earth.
Space Suit Training
We cannot live in the vacuum of space because there is neither air to breathe nor atmospheric pressure to prevent us from hemorrhaging. A space suit is used by the astronauts when they are outside the space ship and exposed to the vacuum of space. A spacesuit is really a balloon shaped like a person and is filled (pressurized) with air. The astronaut inside this balloon is totally surrounded by an artificial atmosphere. Spacesuits are not needed when the astronauts are inside their space ship. The space ship cabin is pressurized with air and is, in fact, a metal balloon with the astronauts inside totally surrounded by the atmosphere within. The outside walls of the cabin must be strong enough to withstand the pressure to prevent the cabin from bursting.
How well do you think you could work if you had to be inside a body-shaped, pressurized balloon? A long, blown-up balloon, such as the arm or finger of a spacesuit, is difficult to bend. We will experience this by blowing up long rubber balloons and bending them. Imagine an astronaut in a pressurized spacesuit doing work and performing tasks, such as tightening a screw, in which bending of the fingers and arms are requirements.
Weightlessness Training
Astronauts in space are weightless. They experience a continuous feeling of falling and have no sense of an up or down direction. These factors can be disorienting, however with proper equilibrium training, the astronauts can learn to overcome the disorientation.
There are other factors resulting from weightlessness that make it difficult for the astronauts to perform work in space. Suppose you have the job of loosening a bolt using a wrench. You place the wrench over the bolt head and pull on the wrench handle to turn the bolt. On Earth, you rely on your weight to provide a frictional force between the bottom of your shoes and the floor so that you can brace yourself to do this job. Suppose that you were standing on very slippery ice or sitting in a chair with wheels. Then, as you pulled on the wrench handle, you would slide or roll across the floor and the wrench would not turn the bolt. Under weightlessness, a similar situation is encountered. You cannot rely on friction between the bottom surface of your shoes and the floor because there is no weight force pressing these two surfaces together. You simply slide as though you were on ice. During our weightlessness training we will use a chair with wheels to simulate this type of loss of frictional forces encountered by the astronauts when performing jobs that require them to brace themselves.
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