For the first time in 40 years, NASA researchers have detected atomic oxygen in Mars‘ atmosphere, thanks to the Stratospheric Observatory for Infrared Astronomy (SOFIA), which soars on a plane 13.7 kilometres (45,000 feet) above Earth.

The oxgyen atoms were found in the Martian upper atmosphere – known as the mesosphere – and the discovery could help astronomers identify how gases escaped from the Red Planet long ago. While this is super exciting for our understanding of Mars – humanity’s potential new home – the researchers found only half the amount of oxygen they expected, but this could be the result of variations in the atmosphere. The last time atomic oxygen was observed in the Martian atmosphere was during the Viking and Mariner missions of the 1970s.

The levels of atomic oxygen detected in the Martian mesosphere were only around half of what was expected. SOFIA will continue to take measurements of Mars’ atomic oxygen levels going forward in an attempt to better understand the Red Planet’s atmosphere.

Sofia is a joint project between Nasa and the German Aerospace Centre.