Great choice! Oxygen and nitrogen are the two main gases in the air we breathe. An oxygen-nitrogen mix is also safer than pure oxygen, because it reduces the chance of fire. Good work!

What else should you have on your space station? Water, of course!

Everybody needs drinking water to survive more than a day or two. But water is very heavy—and it costs $10,000 to launch every pound of payload into space. So how much water do you really need to drink each day?

1 cup (.5 lbs/.27 kg)	2 quarts (4 lbs/1.8 kg)	1 gallon (8 lbs/3.6 kg)
10 gallons, freeze-dried (1 ounce/27 grams)

© The Children's Museum of Indianapolis, 1999