Mars dominated planetary research headlines in 2014 as an international fleet of orbiters and NASA’s two rovers returned unparalleled scientific research on the Red Planet. In 2014, scientists marked Opportunity’s 10-year anniversary on Mars, watched the near miss of comet Siding Spring, and announced Curiosity’s groundbreaking confirmation of the presence of organics on the surface Mars.

Opportunity – 10 years and counting

On 25 January 2004, the Opportunity rover entered the Martian atmosphere, descended on parachute, and then air-bag-dropped onto the surface of Mars, rolling into an impact crater on an otherwise flat plain.

It was the start of a 90 Martian day mission.

Ten years later and 117 months after the mission was supposed to end, NASA and the international space community celebrated the Opportunity’s continued operations and success on the surface of Mars.

In the 10 years that Opportunity has worked on the surface of Mars, her story and the story of her operators has been one of success in the face of seemingly insurmountable obstacles.

Opportunity has not only surpassed all wildly extreme estimates regarding her longevity, but she has also survived five harsh Martian winters, come through an almost certain death when dust storms enveloped the Red Planet in 2007 (which prevented much needed sunlight from reaching her dirty and dust-covered solar panels).

Opportunity has also managed to get stuck in and then be removed from a perilous sand dune that almost caused her permanent immobility in June 2005. She has circumnavigated, entered, and then backed out of Endeavour crater over a two-year period.

Moreover, the rover has been the fortunate recipient of relatively regular wind cleanings of her solar panels – allowing sunlight to continue to power her systems at 96 percent of maximum as of 13 May 2014 (up from 46 percent of maximum on 5 December 2013).

In fact, that is exactly how Opportunity began 2014, with a wind-cleaning event of her solar panels on 1 January 2014.

Operating on the ridge of Endeavour crater to tilt herself toward the Sun for optimal power acquisition in the Martian winter, Opportunity marked its 10th anniversary on the Red Planet, and NASA used that anniversary to announce a new mission objective for Opportunity and its cousin rover, Curiosity.

On 24 January 2014, NASA announced that all ongoing studies on Mars by the two rovers would be geared toward the search for evidence of ancient life in the form of autotrophic (organisms that use light energy or inorganic chemical reactions to produce complex organic compounds from simple substances present in their surroundings), chemotrophic (organisms that obtain energy by the oxidation of electron donors in their environments), or chemolithoautotrophic (organisms capable of using inorganic reduced compounds as a source of energy) microorganisms.

The rovers would also now actively search for ancient water flows or deposits and organic carbon on the surface of the Red Planet.

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For Opportunity, just as she began the year, the rover was the recipient of two major solar panel cleaning events in March. Opportunity started the year producing 371 Watt-hours of energy per day. By 1 April, Watt-hours production had increased to 661.

A further cleaning event coupled with the gradual transition away from winter (longer sunlight hours), brought total Watt-hour production to 764 Watt-hours per day by 27 May 2014.

As winter subsided and power generation increased, Opportunity continued roving around the western edge of Endeavour crater.

The more Opportunity moved, the closer the rover moved toward a record-setting milestone – a record achieved on 27 July 2014.

Following a day’s drive of 157 feet on 27 July, Opportunity’s total distance driven on the surface of Mars reached 40.25 kilometers (25.01 miles).

With that odometer reading confirmed and verified by an international team, Opportunity became the record holder for longest distance driven on a world other than Earth.

The U.S.S.R.’s Lunokhod 2 rover had previously held this record from its four-month lunar mission in 1973.

While initial estimates from the Lunokhod 2 mission, obtained by counting wheel rotation of the rover, reveled a distance traveled of 37 km (23 miles), some debate about the total distance driven by Lunokhod 2 arose following the arrival of NASA’s Lunar Reconnaissance Orbiter (LRO) in lunar orbit in June 2009.

Lunar surface images from NASA’s LRO led scientists at Moscow State University to reassess the distance and assign a total odometer reading of 42.1-42.2 km (26.2 miles) to Lunokhod 2.

This led to an international effort to determine the total distance for Lunokhod 2 and to determine an accurate way of determining comparable and consistent methods for odometer readings of Lunokhod 2 and Opportunity.

Once those methods were determined, Lunokhod 2’s final odometer reading was agreed to: 39 km (24 km).

Thus, on 27 July 2014, when Opportunity’s odometer struck 40 km, the rover exceeded Lunokhod 2’s record and became the vehicle to hold the longest off-world driving record.

Marking the occasion, Mars Exploration Rover Project Manager John Callas, of NASA’s Jet Propulsion Laboratory stated, “Opportunity has driven farther than any other wheeled vehicle on another world.

“This is so remarkable considering Opportunity was intended to drive about one kilometer and was never designed for distance. But what is really important is not how many miles the rover has racked up, but how much exploration and discovery we have accomplished over that distance.”

In recognition of Opportunity’s achievement, and of the science that Lunokhod 2 obtained in 1973, NASA’s Opportunity team named a nearby 20-foot diameter crater (located on the outer slope on the rim of Endeavour crater) Lunokhod 2.

As the rover team took time to mark this driving achievement, they also continued to set their sights on what Opportunity still had to accomplish in the realm of science and driving.

As the Martian winter subsided, Opportunity’s team begun directing the rover toward her next exploration target: Marathon Valley.

The name of the Valley stems from the cumulative driving distance it will take Opportunity to reach this location: 26.2 miles – the distance of a marathon.

With her new target destination confirmed, Opportunity continued her leisurely rover toward Marathon Valley throughout August.

This journey was interrupted 12 times, however, by computer resets (each taking one to two days from which to recover).

With this increase in computer resets, Opportunity’s team began steps to have the rover reformat its flash memory.

A similar reformat had been preformed on Opportunity’s twin rover, Spirit, in 2009 following a series of amnesia events on that rover.

Opportunity successfully completed her flash memory reformat on 4 September 2014 (Sol 3,773). It was the first flash memory reformat for Opportunity in her 10.5 years on Mars.

With her memory fixed, Opportunity resumed her trek toward Marathon Valley before stopping in mid-October to prepare for ground-based observations of Comet Siding Spring’s close flyby of Mars.

On 19 October, Siding Spring made its closet approach to Mars at a distance of just 139,300 km (86,500 miles).

While NASA’s, ESA’s, and India’s fleet of orbiters at Mars (the Mars Reconnaissance Orbiter, Mars Odyssey, MAVEN, Mars Express, and MOM) observed the close passage of the comet and then took shelter behind the planet when Mars passed through Siding Spring’s tail and ejecta plume just hours after close encounter, Opportunity, as well as Curiosity, continued performing scientific observations of the flyby to determine any ground effects from the encounter.

At the time of closest approach, sunrise was eminent at Opportunity’s location, and the sky had begun to brighten. Nonetheless, Opportunity did capture several photos of Siding Spring using its panoramic camera.

Speaking about the flyby, Opportunity science team member Mark Lemmon of Texas A&M University said, “It’s excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the instruments we’re using to study Mars.

“The views from Mars rovers, in particular, give us a human perspective because [the rovers’ cameras] are about as sensitive to light as our eyes would be.”

Following this event, Opportunity and its teams continued the trek toward Marathon Valley.

However, the computer resets and amnesia events that plagued the rover in August – and that were supposed to be fixed by the 4 September computer reformat of the flash memory – returned in a persistent fashion.

During the first week of December, Opportunity’s team once again reformatted the rover’s memory. It was hoped, again, that this would solve the issue, but it did not.

With the failure of the reformat, Opportunity’s team decided to take the step of shifting all working modes of the rover away from any use of flash data-storage systems.

As NASA reported on 11 December, flash memory retains information even when power is shut off during the rover’s overnight power-conserving “sleep” time. In the no-flash mode, the rover can continue normal operations of science observations and driving, but it cannot store data during the overnight sleep.

Therefore, all data gathered each Martian day is stored in volatile memory, which on Opportunity is random-access memory, or RAM. The data stored in volatile memory is then relayed Earthward at the end of Opportunity’s day so that it is not lost when the rover goes to sleep at night.

Currently, Opportunity’s team is developing a set of commands to restore usability of the flash memory through an extensive overhaul that is more structured and intrusive than just reformatting.

While this might sound serious, NASA has said that the incidents of Opportunity’s flash memory not accepting data for storage have occurred in only one of the seven banks of flash microchip circuitry on the rover.

Thus, the team plans to send commands for the rover to avoid that entire bank while still making use of the six working banks of flash microchip circuitry.

In the small chance that this doesn’t work, Opportunity can continue functioning, and the mission can continue in a relatively uninterrupted fashion, using the current configuration – using RAM with daily downloads of data to Earth before sleep.

As Opportunity prepares to enter 2015 and the start of its 11th operational year on Mars, the rover is expected to reach Marathon Valley in early 2015.

Once the 11 year-old rover arrives at Marathon Valley, it will begin investigating clay mineral deposits that have been detected by NASA’s Mars Reconnaissance Orbit.

Curiosity: Confirmation of organic matter on Mars

For Curiosity, 2014 proved to be another banner year at the Red Planet, with the rover observing two asteroids, the Transit of Mercury, the passage of comet Siding Spring, and participating in the discovery of the first confirmation of organic matter, Martian organics, on the surface of Mars.

As the year began, Curiosity’s team was busy collecting photographs and information regarding the roving science laboratory’s surrounding terrain in an effort to find a smoother driving route for Curiosity.

Specifically, the teams were trying to find a more favorable route that would avoid terrain with sharp rocks considered likely to poke holes in the rover’s aluminum wheels.

In the final three months of 2013, punctures and rips on Curiosity’s aluminum wheels from interactions with sharp rocks in Gale crater had accelerated – leaving the rover team to drive Curiosity with added precautions and thorough and frequent checks of the condition of the rover’s wheels.

Normally, the decision to preserve the integrity of the wheels on Curiosity would be a priority. However, in this case, the need to preserve Curiosity’s wheels on a more favorable driving path came up against the obstacle of sand dunes.

In fact, the only way to reach the more favorable driving route identified by Curiosity’s team was to take the rover over a sand dune.

Whenever Curiosity traverses a sand dune, there is always the possibility that the rover could become mired in the sand. Thus, accurately understanding the surrounding terrain and the composition of the sand dune was critical in making the decision of whether or not to send Curiosity over the dune.

The dune in question was about 3 feet high and spanned the gap of two scarps that marked the gateway to the southwestern route over relatively smooth ground.

As discussions about whether or not to send Curiosity over the dune took place, the rover, on 31 January, the 529th Martian day of Curiosity’s tenure on Mars, took its first-ever photographs of the Earth from Mars.

The photograph was captured 80 minutes after sunset on 31 January while Earth and its moon were approximately 99 million miles (160 million km) from Mars.

The photograph’s resolution was high enough to capture not only Earth as the brightest point of light in the Martian twilight sky, but also a clearly visible moon as well.

After this photograph was taken, and after weeks of examination of the surrounding terrain, the decision was made to drive Curiosity over the sand dune, which the rover successfully completed without incident on 6 February.

By mid February, with Curiosity on smooth terrain, the Rover team took the opportunity to test the reverse drive feasibility of the rover.

Reverse driving of Curiosity is designed to help lessen damage to the rover’s wheels when driven over terrain studded with sharp rocks.

According to Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory, “We wanted to have backwards driving in our validated toolkit because there will be parts of our route that will be more challenging.”

With reverse driving validated on Curiosity, the rover continued toward its science waypoint destination approximately two-thirds of a mile (1.1 km) ahead of the rover’s location by mid-February.

This waypoint destination, known as the Kimberly, was chosen for the geological region where four types of terrain with different rock textures intersect.

By the end of March, Curiosity was close enough to the Kimberly to observe some of the characteristics of the region in greater detail than could be discerned based on orbital images.

“The orbital images didn’t tell us what those rocks are, but now that Curiosity is getting closer, we’re seeing a preview,” said Curiosity Deputy Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory.

“The contrasting textures and durabilities of sandstones in this area are fascinating. While superficially similar, the rocks likely formed and evolved quite differently from each other.”

At the same time that Curiosity began distance observations of its waypoint science destination, mission controllers announced that the more desirable and smooth route the rover had been on since February was bearing fruit toward lessening the damage to Curiosity’s wheels.

“The wheel damage rate appears to have leveled off thanks to a combination of route selection and careful driving,” said JPL’s Richard Rainen, mechanical engineering team leader for Curiosity.

“We’re optimistic that we’re doing OK now, though we know there will be challenging terrain to cross in the future.”

In total, the rate of appearance of new holes on the rover’s wheels had dropped to less than one-tenth that of a few months prior when the rover was on more rockier terrain.

With this good news in hand, Curiosity arrived at its waypoint science destination of the Kimberly on 2 April 2014.

Having traveled a total of 3.8 miles (6.1 km) since landing inside Gale Crater in August 2012, Curiosity was now at its second prominent science destination (the first being Yellowknife Bay – where Curiosity had discovered the signature of an ancient lakebed environment providing chemical ingredients and energy necessary for life).

For the Kimberly, “This is the spot on the map we’ve been headed for, on a little rise that gives us a great view for context imaging of the outcrops at the Kimberley,” said Melissa Rice of the California Institute of Technology.

Moreover, this waypoint science destination would be the place where Curiosity’s science instruments would used for the second time to learn more about the habitable past conditions and environmental changes on Mars.

As Curiosity obtained detailed photographs of its surrounding potential science targets at the Kimberly throughout April, the rover turned its Mast Camera toward the sky on 20 April and took the first-ever photograph of asteroids from the surface of Mars.

The two asteroids captured in the photograph were Ceres and Vesta, the two primary orbital targets of the Dawn mission for NASA.

The Dawn mission orbited Vesta in 2011 and 2012 and is currently en route to Ceres to begin orbital operations of that asteroid, also classified as a dwarf planet, in 2015.

The photograph of Vesta and Ceres was captured by Curiosity in a 12-second long exposure in which both asteroids appear as faint streaks.

“This imaging was part of an experiment checking the opacity of the atmosphere at night in Curiosity’s location on Mars, where water-ice clouds and hazes develop during this season,” said camera team member Mark Lemmon of Texas A&M University.

“The two Martian moons were the main targets that night, but we chose a time when one of the moons was near Ceres and Vesta in the sky.”

Back on the ground, with terrain observations of potential science targets ongoing, scientists selected the first rock at the Kimberly to have Curiosity drill into.

A test and mini-drill operation was performed on 29 April to ensure that the location was indeed suitable for drilling.

With that confirmation in hand, Curiosity drilled into its first rock at the Kimberly on Monday, 5 May and followed this operation with the delivery of the drilled rock sample to its onboard science instruments on Tuesday, 6 May.

Drilling marked the third such event for Curiosity since landing on Mars in August 2012. The previous two rock drilling sites were into mudstone targets at Yellowknife Bay.

This third drilling event marked the first time that Curiosity drilled into a slab of Martian sandstone.

The drilling was accomplished using Curiosity’s hammering drill on the rock target nicknamed Windjana.

The drill sample obtained by Curiosity was then sieved and delivered to the rover’s onboard laboratories to determine the mineral and chemical composition.

For these experiments, the Chemistry and Mineralogy instrument (CheMin) and the Sample Analysis at Mars instrument (SAM) were used.

With those samples safely in the rover’s scientific instruments, Curiosity then extended its robotic arm toward the drilled hole and used its camera and spectrometer to examine the texture and composition of the cuttings.

The rover then used its rock-zapping laser to help further investigate the exposed area of rock.

With these observations complete and analysis of the collected rock material underway, mission scientists decided not to drill into any other rocks at the Kimberly waypoint science destination and decided instead to have Curiosity begin roving toward the mission’s primary long-term science destination on the slopes of Mount Sharp.

Curiosity spent the end of May on the move toward Mount Sharp before stopping in early June to witness the Transit of Mercury as seen from the surface of Mars.

The transit event occurred on 3 June 2014 and marked the first transit of the Sun by a planet observed from the surface of any planet other than Earth. (It was in fact the second planetary transit observed from another planet, though that first transit, of Venus as seen from Saturn, was observed by Cassini from Saturn orbit on 21 December 2012.)

The Transit of Mercury from Mars also marked the first imaging of Mercury from Mars (either from orbit or from the ground).

“This is a nod to the relevance of planetary transits to the history of astronomy on Earth,” said Mark Lemmon of Texas A&M University.

“Observations of Venus transits were used to measure the size of the solar system, and Mercury transits were used to measure the size of the sun.”

In all, Mars’s location offers more frequent viewings of Mercury and Venus transits, which can also be seen from Earth, and also has the added benefit of being a location to view the Transit of Earth across the Sun.

From Mars, the next transit event will be of Mercury again in April 2015, followed by the Transit of Venus in August 2030, and finally by the Transit of Earth in November 2084.

Throughout the rest of June and July, Curiosity continued moving toward the slopes of Mount Sharp – which included the traverse of an area of hazardously sharp rocks.

During this traverse of the one-eighth mile rock-studded terrain, Curiosity’s wheels took damage but at a rate far less than expected from pre-traverse estimates.

“The rover drivers showed that they’re up to the task of getting around the really bad rocks,” said Jim Erickson, project manager for Curiosity. “There will still be rough patches ahead. We didn’t imagine prior to landing that we would see this kind of challenge to the vehicle, but we’re handling it.”

By 1 August 2014, Curiosity had approached the exposed bedrock near the foot of Mount Sharp.

Arrival at this bedrock (which Curiosity’s team named “Pahrump Hills”) meant that the mission’s long-term science destination was now just about 2 miles (3 km) southwest of the rover’s location at the beginning of August.

But the bedrock itself offered what scientists referred to as an appetizer at the base layer of the mountain.

“We’re coming to our first taste of a geological unit that’s part of the base of the mountain rather than the floor of the crater,” said Curiosity Project Scientist John Grotzinger of the California Institute of Technology.

By the second week of August, however, Curiosity’s drivers reversed the rover’s course to get it out of an area where ripples of sand filled the floor of a valley (Hidden Valley) Curiosity had driven in to.

The team deemed this sand too hazardous to traverse and backtracked Curiosity onto another route toward the “Pahrump Hills” destination.

When the decision to backtrack Curiosity was made, the rover unexpectedly encountered an area of geologic intrigue in the form of what appeared to be pale paving stones.

“This rock has an appearance quite different from the sandstones we’ve been driving through for several months,” said Curiosity Deputy Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory.

“The landscape is changing, and that’s worth checking out.”

Scientists quickly requested that these pale paving stones become the mission’s fourth drilling target as long as engineers agreed.

After careful analysis, the engineering team did not agree that the pale paving stones were safe enough to drill into because they were unstable.

During a test drill to determine whether future drilling activities were safe to proceed, the rock in question moved slightly at an early stage of the drilling.

Thus, it was determined that drilling operations at the pale paving stones were unfeasible and that Curiosity would continue to drive on an alternate route toward Pahrump Hills to avoid the Hidden Valley sand ripples.

By the end of September, Curiosity had reached Pahrump Hills, and on Wednesday, 24 September 2014, the rover used its hammering drill to chew 2.6 inches of the basal-layer outcrop out of the surface of Mount Sharp – marking the first drilling at the Curiosity’s primary science location.

According to Curiosity Deputy Project Scientist Ashwin Vasavada, “This drilling target is at the lowest part of the base layer of the mountain, and from here we plan to examine the higher, younger layers exposed in the nearby hills.

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“This first look at rocks we believe to underlie Mount Sharp is exciting because it will begin to form a picture of the environment at the time the mountain formed and what led to its growth.”

As Curiosity continued observations at Pahrump Hills, the rover, along with the fleet of Mars orbiters and cousin rover Opportunity, took time in mid-October to observe the passage of comet Siding Spring by Mars.

Like Opportunity, Curiosity was able to obtain ground measurements of atmospheric conditions before, during, and after the passing of Siding Spring.

Curiosity was also able to capture several photographs of Siding Spring from the surface of Mars.

At the time of closest approach, Siding Spring’s apparent magnitude peaked at -6 (roughly the same brightness of a half-moon) and was easily visible to the visual light cameras on Curiosity.

Following these observations, Curiosity resumed full operations at Pahrump Hills.

By the beginning of November, Curiosity’s Chemistry and Mineralogy (CheMin) instrument’s examination of the drill site at Pahrump Hills revealed that the reddish rock powder from that first drill site into a Martian mountain matched the mineral composition map of the base of the mountain obtained from Martian orbit.

“This connects us with the mineral identifications from orbit, which can now help guide our investigations as we climb the slope and test hypotheses derived from the orbital mapping,” said Curiosity Project Scientist John Grotzinger, of the California Institute of Technology.

Specifically, Curiosity’s scientific instrument CheMin revealed that the drill site sample contained much more hematite then any rock or soil sample previously analyzed during Curiosity’s two-year-old mission.

The presence of hematite in the rocks matched observations reported in 2010 by the mineral-mapping instrument on NASA’s Mars Reconnaissance Orbit of this specific region of Mount Sharp.

“We’ve reached the part of the crater where we have the mineralogical information that was important in selection of Gale Crater as the landing site,” said Ralph Milliken of Brown University.

“We’re now on a path where the orbital data can help us predict what minerals we’ll find and make good choices about where to drill.”

And while this announcement held great significance for the future of Curiosity’s mission, it was the mid-December announcement by scientists using data collected by Curiosity in 2013 and 2014 that provided the unexpected yet capstone revelation of the year in terms of planetary science.

On 16 December 2014, NASA announced that Curiosity had definitively detected organic matter on Mars.

The stunning announcement came following continued and careful examination of data returned from Curiosity’s SAM (Sample Analysis at Mars) instrument of rock drill samples obtained by the rover in 2013 of a Sheepbed mudstone rock in Gale Crater named Cumberland.

While the exact nature of the organics presence on Mars has yet to be determined (they could either have formed on the planet or been delivered by meteorites), the discovery is historic in that it marks the first definitive detection of organics in Martian surface materials.

Organic molecules contain carbon and usually hydrogen and are the chemical building blocks of life. While they can exist without the presence of life, life (as known on Earth) cannot exist without them.

Curiosity’s findings from analyzing samples of rock powder from Cumberland do not reveal whether Mars has ever harbored living microbes, but the findings do shed light on favorable conditions for life on ancient Mars.

Despite the fact that these readings were received on Earth months ago, researchers needed to work through the data and make sure that what they were seeing in the data was in fact Martian organics and not organic material transported to Mars by Curiosity itself or created in the SAM instrument.

SAM detected the compounds using its Evolved Gas Analysis (EGA) mode by heating the sample from Cumberland up to about 875 degrees Celsius (around 1,600 degrees Fahrenheit) and then monitoring the volatiles released from the sample using a quadrupole mass spectrometer, which identifies molecules by their mass using electric fields.

SAM also detected and identified the compounds using its Gas Chromatograph Mass Spectrometer (GCMS) mode.

In this mode, volatiles are separated by the amount of time they take to travel through a narrow tube (gas chromatography – certain molecules interact with the sides of the tube more readily and thus travel more slowly) and then identified by their signature mass fragments in the mass spectrometer.

However, the SAM instrument also produces chlorinated hydrocarbons at 22 parts-per-billion of chlorobenzene.

The science teams needed to validate that SAM could not produce the concentrations between 150 and 300 parts-per-billion seen in the samples drilled from Cumberland.

The team spent over a year carefully analyzing the results, running tests on Earth, including conducting laboratory experiments with instruments and methods similar to SAM, to be sure that SAM could not be producing the amount of organic material detected.

The results revealed that there was not way that SAM could produce the 150 and 300 parts-per-billion concentrations seen in the analysis results, giving the team confidence that organic molecules really are present on Mars.

“This first confirmation of organic carbon in a rock on Mars holds much promise,” said Curiosity participating scientist Roger Summons of the Massachusetts Institute of Technology in Cambridge.

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“Organics are important because they can tell us about the chemical pathways by which they were formed and preserved. In turn, this is informative about Earth-Mars differences and whether or not particular environments represented by Gale Crater sedimentary rocks were more or less favorable for accumulation of organic materials.

“The challenge now is to find other rocks on Mount Sharp that might have different and more extensive inventories of organic compounds.”

This major announcement came with the concurring reveal that Curiosity had detected a major spike in methane gas at the end of 2013 and beginning of 2014.

Specifically, the methane announcement centered on the tenfold spike of methane, an organic chemical, in the atmosphere around Curiosity.

According to Sushil Atrey, a rover team member and scientist at the University of Michigan, Ann Arbor, “This temporary increase in methane – sharply up and then back down – tells us there must be some relatively localized source. There are many possible sources, biological or non-biological, such as interaction of water and rock.”

The methane measurements were made using SAM. A total of 12 samples of the local Martian atmosphere were collected over a 20-month period to “sniff” for methane.

In late 2013 and early 2014, four measurements in two months revealed an averaged seven parts-per-billion concentration of methane gas, a sharp increase from the ambient average of only one-tenth that level in the other 18 months of observation.

These discoveries are a major and significant step forward in our understanding of Mars’s current condition and former environment.

Data collected from telescopic, rover, and orbiter missions has shed light on Mars’s past ability to host life – a possibility that increases as we gather more information on the Red Planet.

“We think life began on Earth around 3.8 billion years ago, and our result shows that places on Mars had the same conditions at that time – liquid water, a warm environment, and organic matter,” said Caroline Freissinet of NASA’s Goddard Space Flight Center.

“So if life emerged on Earth in these conditions, why not on Mars as well?”

(Images via NASA JPL).