Martian atmosphere

NASA just detected oxygen in the Martian atmosphere

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NASA has detected oxygen in the upper Martian atmosphere with the help of an instrument on board the Stratospheric Observatory for Infrared Astronomy (SOFIA). Oxygen had been discovered on the red planet before; however, this is the first time its presence has been verified in wake of the Viking and Mariner missions more than 40 years ago.

The oxygen atoms were detected in the upper atmosphere of Mars called the mesosphere. The discovery will help shed light on how gases escaped from the Martian atmosphere millions of years ago. Although oxygen has been detected on Mars in the past, the amount of oxygen detected was half of what the researchers anticipated, which may be due to differences in the atmosphere.

“Atomic oxygen in the Martian atmosphere is notoriously difficult to measure,” said Pamela Marcum, a project scientist with SOFIA, in a press statement. “To observe the far-infrared wavelengths needed to detect atomic oxygen, researchers must be above the majority of Earth’s atmosphere and use highly sensitive instruments, in this case a spectrometer. SOFIA provides both capabilities,” she added.

Because Earth’s atmosphere is dense and moist, it is difficult to get a clear image of what lies beyond it. To overcome this hurdle, the researchers utilized SOFIA, a Boeing 747SP jetliner, which has a 100-inch diameter telescope latched to it.

The project is a joint collaboration between NASA and the German Aerospace Center. ASA’s Ames Research Center in Moffett Field, California, oversees the SOFIA program. The aircraft is based at NASA’s Armstrong Flight Research Center’s hangar 703 in Palmdale, California, according to NASA’s website.

Sofia flew approximately 37,000–45,000 feet above most of the infrared-blocking moisture in Earth’s atmosphere. New detectors on one of the observatory’s instruments, the German Receiver for Astronomy at Terahertz Frequencies (GREAT), helped the astronomers discern between oxygen in Earth’s atmosphere versus oxygen in Mars’s atmosphere.

The high vantage point and the specialized instrumentation that is tuned to look past Earth’s atmosphere helped the researchers make their calculations. Although the team has yet to provide precise figures on how much atomic oxygen is in the Martian mesosphere, they did claim it is lower than expected. As a result, the researchers will keep implementing SOFIA to probe other regions of the red planet to make sure the figure wasn’t simply the result of variations in the atmosphere.

How the Martian atmosphere became so thin.

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New findings from NASA’s Curiosity rover provide clues to how Mars lost its original atmosphere, which scientists believe was much thicker than the one left today.

“The beauty of these measurements lies in the fact that these are the first really high-precision measurements of the composition of Mars’ atmosphere,” said Sushil Atreya, professor of atmospheric, oceanic and space sciences at the University of Michigan.

Atreya is co-author of two related papers published in the July 19 issue ofScience, and co-investigator on Curiosity’s Sample Analysis at Mars (SAM) suite of instruments, considered the rover’s cornerstone lab.

SAM measured the abundances of different gases and isotopes in samples of Martian air, according to NASA. Isotopes are variations of the same chemical element that contain different numbers of neutrons, such as the most common carbon isotope, carbon-12, and a heavier stable isotope, carbon-13, which contains an additional neutron.

SAM analyzed the ratios of heavier to lighter isotopes of carbon and oxygen in the carbon dioxide that makes up most of Mars’ atmosphere today. Measurements showed that heavy isotopes of carbon and oxygen were more abundant in today’s thin atmosphere compared with the proportions in the raw material that formed the planet (which scientists can deduce from proportions in the sun and other parts of the solar system.) This provides not only supportive evidence for the loss of much of Mars’ original atmosphere, but also gives clues to how the loss occurred. It suggests that the planet’s atmosphere escaped from the top, rather than due to the lower atmosphere interacting with the ground, NASA’s web story states.

“The isotope data are unambiguous and robust, having been independently confirmed by the quadrupole mass spectrometer and the tunable laser spectrometer, two of the SAM suite instruments,” Atreya said. “These data are clear evidence of a substantially more massive atmosphere, hence a warmer, wetter Mars in the past than the cold, arid planet we find today.”

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