#astronomy NASA’s Curiosity Takes Step Towards Fixing Mars Methane Thriller – Sky & Telescope

July 7, 2021 - Comment

The wheels of NASA’s Curiosity trip over the Martian panorama in Gale Crater. This picture was taken by a digital camera on the rover’s arm.NASA / JPL-Caltech / MSSS Researchers already suspected it, however now they’ve proof. The focus of methane above Gale Crater, the touchdown website of the Curiosity rover, modifications from day to

The wheels of the Mars Curiosity RoverThe wheels of NASA’s Curiosity trip over the Martian panorama in Gale Crater. This picture was taken by a digital camera on the rover’s arm.
NASA / JPL-Caltech / MSSS

Researchers already suspected it, however now they’ve proof. The focus of methane above Gale Crater, the touchdown website of the Curiosity rover, modifications from day to nighttime. It goes from low however measurable ranges through the evening to concentrations close to zero through the day. That day by day cycle might assist clarify why totally different devices had been seeing, and never seeing, methane.

Scientists have spent a long time chasing methane on Mars. On Earth, the gasoline is usually a signal of microbial exercise, however it may also be a product of chemical reactions between liquid water and sure minerals. Discovering methane within the Martian environment may reveal that comparable processes are occurring underground on the Pink Planet.

Curiosity first sniffed methane on Mars on June 15, 2013. Since then it has discovered that background ranges fluctuate between zero.2 and zero.7 elements per billion in quantity (ppbv). Subsequent measurements counsel that methane abundances may comply with a seasonal sample, with extra of the gasoline current through the summer time and fewer within the winter (though a current statistical evaluation says that interpretation will not be statistically sound).

Curiosity additionally detected occasional peaks in methane focus, often called plumes, which reached a most of 20.5 ppbv on June 19, 2020. In 2013, considered one of these plumes was detected concurrently by Curiosity and the European Area Company (ESA) Mars Categorical orbiter.

Scientists speculate that methane may very well be leaking from the Martian underground, the place it’s both generated by ongoing processes or saved in reservoirs shaped within the distant previous. Alternatively, the gasoline may kind on the floor when photo voltaic ultraviolet radiation breaks up meteoritic mud that falls onto the planet from outer house.

methane creation possibilities on MarsThere are a number of methods so as to add methane to Mars’s environment (and take it away once more). Though microbes are essentially the most thrilling chance, different probably sources embody reactions between water and the minerals olivine or pyroxene, or photo voltaic ultraviolet radiation breaking apart meteoritic mud on the planet’s floor.
NASA / JPL-Caltech / SAM-GSFC / Univ. of Michigan

However in April 2019, the ESA’s ExoMars Hint Gasoline Orbiter, a spacecraft particularly designed to measure vanishingly small concentrations of gases within the Martian environment, failed to seek out indicators of methane after a number of months of operation. A collaborative undertaking between ESA and Roscosmos, TGO appears to be like at daylight because it travels by way of the higher layers of the environment, 5 kilometers above the bottom, and will be capable of detect particle concentrations as little as zero.05 ppbv. That’s 10 instances lower than what was being routinely measured by Curiosity.

After months of heated debate, a gaggle of researchers led by John Moores (York College, Canada), realized that the discrepancy may boil all the way down to the time of day the measurements had been taken. “What in the event that they’re each proper, what does that inform us about Mars?” Moores puzzled. “Then you definitely’ve received to have methane altering over the course of the day.”

Curiosity’s chemistry lab is an influence hog. Each time it does a methane run, the Tunable Laser Spectrometer (TLS) contained in the Pattern Evaluation at Mars (SAM) pumps in Martian air for a number of hours. For that motive, these runs have all the time been executed at evening, when no different devices are working. The Martian environment is cool and calm at evening, Moores famous, making it extra probably that it’s going to maintain onto any molecules slipping out from an underground supply. However whereas Curiosity was in a position to detect the methane on the floor, the TGO was wanting on the environment at sundown, after a whole day of Solar-driven atmospheric mixing, when the methane may already be too diluted to select up.

Artist's depiction of Schiaparelli lander separating from the Trace Gas OrbiterAn artist’s impression of the ESA’s ExoMars Hint Gasoline Orbiter hovering over Mars after separating from its lander, Schiaparelli.
ESA/ATG medialab

To check the thought, the Curiosity staff tried a few methane runs through the day. TLS bracketed one nighttime measurement with two daytime ones. The nighttime measurement yielded zero.52 ppbv, according to earlier outcomes, whereas the 2 daytime measurements picked up no methane in any respect, confirming Moores’s prediction.

“We’re certain that the bottom in Gale crater is leaking methane, even on the low ranges noticed,” says Chris Webster (Jet Propulsion Laboratory), principal investigator of the TLS instrument. “Our new knowledge take an necessary step towards reconciling the Curiosity and ExoMars knowledge units.” Webster and his staff reported these leads to the June Astronomy & Astrophysics.

Even when they’re proper, although, the speed of methane seeping from underground reservoirs into the environment have to be very low. Moores and his colleagues estimated most of two.eight kilograms of methane escaping from Gale Crater each day may clarify Curiosity’s measurements with out rising world ranges above TGO’s zero.05 ppbv detection restrict.

Then once more, it’s not possible that Gale Crater is the one place on Mars that leaks methane. If all the same craters on Mars spewed methane on the similar fee, the gasoline would over time construct as much as ranges TGO may detect. Methane molecules ought to survive for a median of 300 years within the Martian environment earlier than photo voltaic radiation tears it aside, however TGO’s nondetection suggests one thing else is occurring. “Methane must be destroyed far more quickly,” Moore says.

gale crater shown with Curiosity landing site.A birds eye view of Gale Crater, the place methane detections (and non-detections) had been made by NASA’s Curiosity rover. This picture is a composite of information from three Mars orbiters. The crater itself is nearly 154 km (96 mi) in diameter. Curiosity’s touchdown spot is denoted by the ellipse.
NASA / JPL-Caltech / ESA / DLR / FU Berlin / MSSS

Experiments are underway in a number of labs on Earth to find out what may very well be destroying methane. One chance is that small electrical discharges between suspended mud grains may very well be accountable. One other chance is that the gasoline is reacting with the oxygen-rich Martian floor in methods not predicted by present photochemical fashions. Possibly methane is simply getting caught to the mud floating within the environment.

Moores thinks we’d like extra measurements from the bottom. Curiosity has made about 16 measurements in a decade. “It is a very coarse knowledge set and you’ll think about that it have to be tough to determine what occurs over the day for those who solely measure each six months.”

“Neither the Perseverance or Chinese language rovers are in a position to measure Mars methane at any stage,” Webster says. He suggests mini-TLS, both launched on an impartial mission or piggybacking on a deliberate future mission, may determine how a lot and the way typically methane is launched to assist settle its supply.


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