EXPLORING THE ELEMENTS Oxygen Avery Elizabeth Hurt Enslow Publishing 101 W 23rd Street Suite 240 New York NY 10011 USA enslow com
Introduction On July 20 1969 for the first time humans stepped out of their spacecraft and walked on the surface of another heavenly body The Apollo mission to the Moon was one of the greatest scientific scientific achievements of the twentieth century Now in the twenty first century humans are exploring Mars but how will they breathe upon arrival As early as the 1960s and 1970s the United States and the Soviet Union began studying Mars In the 1960s both nations sent spacecraft on flybys of Mars to take photographs and gather information from orbit In 1965 NASA’s Mariner Four got the first close-up images of Mars and in 1971 the Soviets sent a lander to the surface of Mars It crashed on landing but a second attempt survived long enough to send back twenty seconds of useful video From 1975 to 1980 two NASA orbiters and landers Viking 4
IntroductIon 5 One and Viking Two mapped the Red Planet and searched for signs of life In 1997 NASA placed the first-ever surface lander and the rover Sojourner on Mars In 2003 the European Space Agency joined the exploration of Mars sending landers and orbiters In 2011 NASA sent Curiosity the larg est and most sophisticated exploration rover ever to visit another planet Curiosity explored for two years and found evidence that liquid water had once existed on Mars of the twentieth century On July 20 1969 humans first set foot on the moon The Apollo 11 mission to the moon was one of the greatest scientific achievements But as exciting as these missions have been no humans have visited visited Mars That may change soon In 2017 NASA outlined its plans to send a manned mission to the Red Planet by 2033 But plans for Mars are a great deal bigger than those for the moon Scientists hope to one day colonize Mars If people are going to live work and study on Mars they are going to need something Mars doesn’t have much of oxygen The Martian atmosphere is 96 percent carbon dioxide and less than 2 percent oxygen Getting humans to Mars is a big challenge
