Isaac Newton • Newton’s discovery of gravity helped us overcome the obstacles of space travel. • During the latter part of the 17th century, the scientific foundations for modern space travel was laid out by the great English scientist Sir Isaac Newton (1642-1727). Newton organized his understanding of physical motion into three scientific laws. The laws explain how rockets work and why they are able to work in the vacuum of outer space. Newton's laws soon began to have a practical impact on the design of rockets.
Using models of the Solar System • In all aspects of science and math we use models • Models have limitations. (They cannot always accurately portray every aspect of the object they are representing) • How can models of the solar system be used to study space? • What would be some limitations of a black and white picture of a solar system?
Leaving Earth • Living in space is not as easy as it looks on TV and in the movies. Think about what you learned in the last lesson about how different temperatures and atmospheres were in different celestial bodies. The distance from the Sun affects how much solar radiation arrives at that planet or object. Too much solar radiation can kill humans if they do not have protection from the radiation. • Earth’s atmosphere protects us by • Shielding Earth from collisions with other particles like meteoroids • Protects us from radiation from the sun • Helps the Earth maintain a range of temperature suitable for life • Allows for gas exchange between plants and animals
Living and working in space • Space is huge and the distances between the objects are very great. • It is generally cold and dark. • Humans sense of time and speed are not accurate in space. • Living in a small crowded area can be depressing.
Astronauts suits • Astronauts suits have to provide for basic needs of the astronaut. • They must insulate them from extreme temperatures in space. • They must equalize the air pressure. • They must provide for body waste management. • The space suit provides air pressure to keep the fluids in your body in a liquid state -- in other words, to prevent your bodily fluids from boiling. • They provide pure oxygen for breathing and have canisters to collect exhaled CO2 • Provide some protection from radiation • Provide communications • Provide mobility within the suit (special joints and tapirs to help move)3 • Therefore, spacecraft are equipped with footholds and hand restraints to help astronauts work in microgravity. http://science.howstuffworks.com/space-suit1.htm
Effects of microgravity on the body • Orbiting in space creates a nearly weightless effect for humans called microgravity. You can experience microgravity when riding roller coasters or jumping on a trampoline or off a diving board. It is the “free fall” period of these activities when the microgravity occurs. • The space shuttle is held in orbit by gravity as it “falls” around the Earth. The force of microgravity is the shuttle is 1 x 10 -6 gravity, so objects appear to be floating. It is sometimes called Zero gravity, but is more accurately named microgravity because it is so slight.
Effects of microgravity on the body • Since weight is measured by the pull of gravity on a mass, and a mass is the amount of matter in a substance, astronauts lose weight, due to less gravity. They will also lose some muscle mass because they do not use their muscles as much because of the lesser gravity. If muscles are not used they will atrophy. • Astronauts also lose blood volume in space. • Higher blood pressure in the head raises an alarm: The body has too much blood! Within two to three days of weightlessness, astronauts can lose as much as 22 percent of their blood volume as a result of that errant message. This change affects the heart, too. "If you have less blood," explains Dr. Victor Schneider, research medical officer for NASA headquarters, "then your heart doesn't need to pump as hard. It's going to atrophy."
Effects on cardiovascular system • Human beings living on Earth are affected by gravity because about two-thirds of our daily activities are standing or sitting. Because of this great amounts of body fluids such as blood pool in the lower part of the body. The human body is equipped with various mechanisms to oppose gravity to maintain sufficient blood flow to the brain. In micro gravity environment, the quantity and the distribution of body fluid alters since it is free of the gravitational effect. This is the known as "fluid shift." Symptoms caused by fluid shift are stuffy nose, headache, and puffy face.
Effects on skeletal System • Bones are systems involved in maintaining posture. • In space, because of microgravity, the amount of physical stress on the bones is decreased so bone density decreases and bones deteriorate (weaken).
Space food • Microgravity will also cause water to form a ball rather than a water drop shape. This can cause problems showering, perspiring and drinking. Food is prepared differently and may different. Many astronauts request hot sauce and spices to improve the flavor of the food.
Spacecraft • Sleeping is challenging in microgravity. Sleeping bags are strapped to the walls of the craft and the astronauts must secure themselves in. The rhythmic beating of the heart can even cause the head to bob, so the head must be secured also.
Pressure, temperature, and atmosphere changes • Providing a clean air supply, water supply, temperature control, must also be considered.
Waste Removal ? • Waste management in space is rather interesting. Astronauts use flushing toilets with air rather than water. The airflow draws the waste away from the body, and then flushes it in to storage tanks. The liquid is dumped overboard and eventually evaporates. Solid waste is stored in a container, dries out, and is taken back to Earth for disposal.