NASA’s 747 makes first measurement of Martian oxygen since 1970s

Ars Technica : In the 1970s NASA’s Viking lander found that Mars’s atmosphere was 95% carbon dioxide, with only minuscule levels of the nitrogen and oxygen that are a significant part of Earth’s atmosphere. Over the past 40 years, no subsequent measurements of those trace gases in the Martian atmosphere have been made. Now NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) has taken a look at Mars’s upper atmosphere, where it measured levels of oxygen that were about half of what Viking measured. SOFIA is a Boeing 747 that is specially modified to fly at an altitude of 45 000 ft (13.7 km) and is equipped with a highly sensitive spectrometer that enables measurements in the far-IR. The SOFIA team says the lower-than expected oxygen levels are likely the result of an uneven distribution of the gas in the atmosphere caused by localized releases of oxygen from chemical reactions in the Martian soil.