NASA’s Curiosity Rover Discovers More Signs of Habitability on Mars; Past and Present

NASA’s Curiosity rover has discovered ancient organic molecules
on Mars, including the molecule thiophene, embedded within sedimentary rocks at
Gale Crater that are billions of years old. 
The rover used an instrument called SAM (Sample Analysis at Mars).  Credit:  NASA/GSFC

Ken Kremer     15
June 2018

FL –  NASA’s Curiosity rover has
discovered additional signs of habitability on Mars at the robots Gale Crater
landing site, both past and present in the form of organic molecules and gaseous
methane, that represent “
breakthroughs in astrobiology,” researchers announced.

Curiosity has detected
a variety of organic molecules including thiophene in ancient sedimentary rocks
as well as seasonal variations in the levels of methane in the atmosphere,
according to new findings announced at a NASA briefing as well as in new papers
published in the journal Science on June 8.

By analyzing cored sedimentary rock samples fed into
Curiosity onboard Sample Analysis at Mars (SAM) instrument suite
researchers have provided “conclusive evidence for the
presence of organic compounds—thiophenic, aromatic, and aliphatic compounds—in
drill samples from Mars’ Gale crater,” in one of the newly published Science papers
by lead author Jen Eigenbrode, et al.
In a second paper
by lead author Chris Webster, et al, researchers report “
strong seasonal variation in atmospheric methane, the simplest organic
molecule, in the martian atmosphere.”
“Both these finding are breakthroughs
in astrobiology
,” writes Inge Loes
ten Kate
, of
University, Utrecht, Netherlands,
in a third paper in Science.
Organic molecules are among the building blocks and
prerequisites of life, although in and of themselves are not definitive proof
of life and can be created by non-biological
NASA’s Curiosity rover used an instrument called SAM (Sample
Analysis at Mars) to detect 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. 
Credit:   NASA/JPL-Caltech
“NASA’s Curiosity rover has found new evidence
preserved in rocks on Mars that suggests the planet could have supported
ancient life, as well as new evidence in the Martian atmosphere that relates to
the search for current life on the Red Planet. While not necessarily evidence
of life itself, these findings are a good sign for future missions exploring
the planet’s surface and subsurface,” NASA said in a statement.
“Although the surface of Mars is inhospitable
today, there is clear evidence that in the distant past, the Martian climate
allowed liquid water – an essential ingredient for life as we know it – to pool
at the surface. Data from Curiosity reveal that billions of years ago, a water
lake inside Gale Crater
held all the ingredients necessary for life, including chemical building blocks
and energy sources.” 
Although Curiosity
has detected other chlorinated organics and signs habitability in past
findings, these new discoveries significantly expand the scope, variety and
complexity of the organics.  
“We found organic molecules in rocks from an
ancient lakebed,” said Jen Eigenbrode, a research scientist at
NASA’s Goddard Space
Flight Center in Greenbelt, Maryland.
“Those organic
molecules could have come from life.”
Curiosity obtained the new data on martian organics
data by drilling into sedimentary “mudstone” rocks from four locations in Gale
Crater that formed billions of years ago “from silt that accumulated at the
bottom of the ancient lake” and analyzing them with the SAM instrument.
SAM heats the samples to over 900 degrees
Fahrenheit (500 degrees Celsius) and thereby release the organic molecules in
gaseous form from the powdered rock.
“The results also indicate organic carbon
concentrations on the order of 10 parts per million or more. This is close to
the amount observed in Martian meteorites and about 100 times greater than
prior detections of organic carbon on Mars’ surface. Some of the molecules
identified include thiophenes, benzene, toluene, and small carbon chains, such
as propane or butene.”
“In 2013, SAM detected some organic molecules
containing chlorine in rocks at the deepest point in the crater. This new
discovery builds on the inventory of molecules detected in the ancient lake
sediments on Mars and helps explains why they were preserved.”

NASA’s Curiosity rover raised robotic arm
with drill pointed skyward while exploring Vera Rubin Ridge – backdropped by
the base of Mount Sharp inside Gale Crater. This navcam camera mosaic was
stitched from raw images taken on Sol 1912, Dec. 22, 2017 and colorized.
Credit: NASA/JPL/Ken Kremer/ Di Lorenzo

Curiosity also used another instrument in the SAM suite to
detect methane over a period of three
Mars years or almost six Earth years.
“Today, we’re announcing the discovery of a repeatable,
identifiable, seasonal pattern in the methane measurements,” said Chris
Webster, a senior research fellow at NASA’s Jet Propulsion Laboratory (JPL) in
Pasadena, California.
“This is the first time we’ve seen
something repeatable in the methane story, so it offers us a handle in
understanding it.  This is all possible
because of Curiosity’s longevity. The long duration has allowed us to see the
patterns in this seasonal ‘breathing.'” 
“Not only have we got this wonderful repeatability, but the
seasonal cycle changes by a factor of three. That’s a huge change, completely
unexpected. And what it does, it gives us a key to unlocking the mysteries
associated with Mars methane because now we have something to test our models
and our understanding against.”
The Curiosity Mars rover snaps a dramatic
selfie at the ‘Torridon’ quadrangle while making long stretches of wheel tracks
exploring assorted rock layers, bedrock outcrops and mineral exposures around
Vera Rubin Ridge with an exquisitely sharp view of the distant rim of the Gale
Crater landing site visible in the background on the Red Planet.
navcam camera mosaic was stitched and colorized by Ken Kremer and Marco Di
Lorenzo using raw images taken on Sol 1896, Dec. 6, 2017.
NASA/JPL/Ken Kremer/ Di Lorenzo/

NASA’s next planned Red Planet rover is under construction
and launching in 2020. These findings give more confidence that scientists are
on the right track in searching for evidence life beyond Earth and potentially on
“With these new findings, Mars is telling us to
stay the course and keep searching for evidence of life,” said Thomas
Zurbuchen, associate administrator for the Science Mission Directorate at NASA
Headquarters, in Washington, in a statement.
“I’m confident that our ongoing and planned
missions will unlock even more breathtaking discoveries on the Red Planet.”

NASA’s InSight lander is on its way to the Red Planet after launching
on May 5 for a landing in November 2018. 

NASA’s Martian fleet also comprises 3 orbiters.

Curiosity is currently exploring the lower
sedimentary layers of Mount Sharp which tower over 3 miles (5.5 km) into the Martian
sky and found that is supported a habitable zone
billions of years ago. 

“Curiosity has shown that Gale crater was
habitable around 3.5 billion years ago
with conditions comparable to those on the
early Earth, where life evolved around that time,” wrote
Loes ten Kate
“The question of whether life might have
originated or existed on Mars is a lot more opportune now that we know that
organic molecules were present on its surface at that time.
As of today, Sol 2082, June 15, 2018, Curiosity has driven
11.85 miles (19.07 kilometers) since its August 2012 landing inside Gale Crater from the
landing site to Mount Sharp and taken over 501,100 amazing images. 

Watch for Ken’s continuing onsite coverage of NASA, SpaceX, ULA,
Boeing, Lockheed Martin, Orbital ATK and more space and mission reports direct
from the Kennedy Space Center, Cape Canaveral Air Force Station, Florida and
Wallops Flight Facility, Virginia.

Stay tuned here for Ken’s continuing Earth and Planetary science and human
spaceflight news:
– – twitter @ken_kremer – email: ken at

Ken Kremer

Watch for Ken’s continuing onsite coverage of NASA, SpaceX, ULA, Boeing, Lockheed Martin, Northrop Grumman and more space and mission reports direct from Kennedy Space Center and Cape Canaveral Air Force Station in Florida and Wallops Flight Facility in Virginia. Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news. Dr. Kremer is a research scientist and journalist based in the KSC area, active in outreach and interviewed regularly on TV and radio about space topics. Ken’s photos are for sale and he is available for lectures and outreach events.

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