What do you need to survive on Earth? Water, air (oxygen), a way to warm up when it is cold, a way to cool down when it is hot, food, and protection from radiation. This last one is not something we think about, but it is a necessary part of survival here on Earth. The sun puts out a lot of radiation that is quite deadly. However, the Earth's atmosphere protects us from the radiation. In this activity, you will learn what is necessary to survive in space.

So what is different in space? We still need water, oxygen, food, a way to get warm or cool down, and protection from radiation. But we also need to protect ourselves from other objects in space.

It may sound like science fiction, but scientists are trying to find ways to create a force field around space ships to protect them from being hit. This force field may also be used to protect the astronauts from radiation from the sun.

There are many things to take into consideration before humans can live in space for the long periods necessary to reach other planets. Dr. Valeri Polyakov, a Russian cosmonaut, was in space from January 8, 1994 to March 1995. He holds the record for the longest continuous stay in space. When he returned to Earth, his muscles and bones were weak because of the lack of gravity in space. This is a major concern for anyone travelling to another planet. We will look at gravity in an upcoming activity. 

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Another thing that must be taken into consideration is having a way to recycle the air so it is pure enough to breath. Scientists must also perfect recycling water waste into drinkable water. Finally, it may be necessary for astronauts to grow their own food on long space flights.

Living in space is not the same as living on Earth. In space, astronauts' bodies change. On Earth, our lower body and legs carry our weight. This helps keep our bones and muscles strong. In space, astronauts float. They do not use their legs much. Their lower backs begin to lose strength. Their leg muscles do too. The bones begin to get weak and thin. This is very bad for astronauts' bodies. So, how do astronauts help their muscles and bones? They must exercise in space every day. 

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While all of these things are being worked on, they must be perfected before any flights to other planets can take place. Safety first is the key. Once the astronauts have left the Earth's gravity, there is no rescue possible if something goes wrong. That is why everything must work perfectly before humans attempt to go to other planets. In the next two activities, you will learn more about water, air, gravity, and temperature in space.