Exploring the Elements: Oxygen

Exploring the Elements: Oxygen — page 1
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