Curiosity Mastcam Right photo acquired on Sol 2443, June 21, 2019.
Credit: NASA/JPL-Caltech/MSSS



NASA’s Curiosity Mars rover is now performing Sol 2445 duties.

An evolving story is that the Mars machinery has once again detected whiffs of methane – perhaps tied to microbes presently resident on the Red Planet.

“Mars, it appears, is belching a large amount of a gas that could be a sign of microbes living on the planet today,” reported the New York Times on Saturday, June 22.

Responds Thomas Zurbuchen, NASA Associate Administrator of the Science Mission Directorate: “While increased methane levels measured by Curiosity are exciting, as possible indicators for life, it’s important to remember this is an early science result. To maintain scientific integrity, the science team will continue to analyze the data before confirming results.”

Sample Analysis at Mars (SAM) instrument.

Follow-up studies

The robot detected the atmospheric methane using its Sample Analysis at Mars (SAM) instrument. This detection reportedly has called for follow-up studies with results of new observations expected on Monday.

The SAM instrument suite takes up more than half the science payload on board the rover. Provided by NASA’s Goddard Space Flight Center, SAM features chemical equipment found in many scientific laboratories on Earth and searches for compounds of the element carbon — including methane — that are associated with life and explores ways in which they are generated and destroyed in the Martian ecosphere.

June 2018 graphic relates that SAM detected seasonal changes in atmospheric methane in Gale Crater.
Credit: NASA/JPL

Seasonal changes

Back in June 2018, NASA announced that SAM detected seasonal changes in atmospheric methane in Gale Crater. The methane signal has been observed for nearly three Martian years (nearly six Earth years), peaking each summer.

In a press statement from the Jet Propulsion Laboratory, the fact that Curiosity detected last week unusually high methane levels, the finding is characterized as a surprising result: “The largest amount of methane ever measured during the mission — about 21 parts per billion units by volume (ppbv). One ppbv means that if you take a volume of air on Mars, one billionth of the volume of air is methane.”

Sample inlet (one open) of the rover’s Sample Analysis at Mars (SAM) instrument suite.
Credit: NASA/JPL-Caltech/MSSS

“Curiosity doesn’t have instruments that can definitively say what the source of the methane is, or even if it’s coming from a local source within Gale Crater or elsewhere on the planet.”

Explains SAM Principal Investigator Paul Mahaffy of NASA’s Goddard Spaceflight Center in Greenbelt, Maryland: “With our current measurements, we have no way of telling if the methane source is biology or geology, or even ancient or modern.”

Picture perfect: A selfie taken by NASA’s Curiosity Mars rover on Sol 2291 (January 15) at the “Rock Hall” drill site, located on Vera Rubin Ridge.
This was Curiosity’s 19th drill site. The drill hole is visible to the rover’s lower-left.
Credit: NASA/JPL-Caltech/MSSS

According to the JPL press statement: “The Curiosity team has detected methane many times over the course of the mission. Previous papers have documented how background levels of the gas seem to rise and fall seasonally. They’ve also noted sudden spikes of methane, but the science team knows very little about how long these transient plumes last or why they’re different from the seasonal patterns.”

The SAM team organized a different experiment for this past weekend to gather more information on what might be a transient plume. “Whatever they find — even if it’s an absence of methane — will add context to the recent measurement.”

Artist’s impression of the European Space Agency’s ExoMars 2016 Trace Gas Orbiter at the Red Planet..
Credit:ESA/ATG medialab

ESA collaboration

Lastly, the JPL statement explains that Curiosity’s scientists need time to analyze these clues and conduct many more methane observations.

“They also need time to collaborate with other science teams, including those with the European Space Agency’s Trace Gas Orbiter, which has been in its science orbit for a little over a year without detecting any methane. Combining observations from the surface and from orbit could help scientists locate sources of the gas on the planet and understand how long it lasts in the Martian atmosphere. That might explain why the Trace Gas Orbiter’s and Curiosity’s methane observations have been so different.”

Meanwhile, the rover Curiosity is examining the outcrop on top of “Teal Ridge,” described as a “spectacular sedimentary outcrop,” by Abigail Fraeman, a planetary geologist at NASA/JPL in Pasadena, California.

Go to the New York Times story here:

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