LIFE IN SPACE
Exploring something new means taking risks. Even with careful planning, two problems can’t be avoided. Space is dangerous. And the human body isn’t built for space.
The human b
1 MIND After months in space, astronauts begin to feel tired. It's hard to sleep. Carbon dioxide and other substances in the environment can cause this to happen.
2 EYES Without gravity, fl uids move upward. This puts pressure on the nerve behind the eye. This can affect an astronaut's vision.
illustration of space junk SPACE IS DANGEROUS.
How does a rocket escape Earth's atmosphere? It travels very fast. Faster than 40,000 kilometers per hour (25,000 miles per hour)! Soon it clears Earth’s gravity, passing a minefi eld of junk.
More than 17,000 objects orbit Earth. Each is at least the size of a softball. Some objects, including satellites, are pretty big. Other objects are smaller than 10 centimeters (4 inches). Add large and small objects together. Then the count jumps to around 500,000 objects. At the speed they are moving, they could cause serious damage to the ship.
There are other dangers, too. Out in space, tiny particles zip around at close to the speed of light. This space radiation can harm the human body.
3 IMMUNE SYSTEM This system protects the body against disease. However, it slows down in space. This can weaken an astronaut’s ability to fi ght off sickness.
4 DIGESTION Tiny organisms in the gut are needed to digest food. Radiation can damage this system.
5 BLOOD On Earth, the heart works against gravity. It pumps blood. It keeps it from pooling in the legs. In space, there's no gravity to pull blood down. Instead, blood goes to the chest and head. Astronauts can develop puffy faces and skinnier legs.
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NATIONAL GEOGRAPHIC EXPLORER
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