Curiosity Mars Rover Begins Study of Ridge Destination

The car-size NASA rover on a Martian mountain, Curiosity, has
begun its long-anticipated study of an iron-bearing ridge
forming a distinctive layer on the mountain’s slope.

Since before Curiosity’s landing five years ago next month,
this feature has been recognized as one of four unique terrains
on lower Mount Sharp and therefore a key mission destination.
Curiosity’s science team informally named it “Vera Rubin Ridge”
this year, commemorating astronomer Vera Cooper Rubin
(1928-2016).

“Our Vera Rubin Ridge campaign has begun,” said Curiosity
Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion
Laboratory, Pasadena, California. “Curiosity is driving
parallel to the ridge, below it, observing it from different
angles as we work our way toward a safe route to the top of the
ridge.”

A major appeal of the ridge is an iron-oxide mineral, hematite,
which can form under wet conditions and reveal information
about ancient environments. Hematite-bearing rocks elsewhere on
Mars were the scientific basis for choosing the 2004 landing
site of an older and still-active rover, Opportunity. Studies
of Mount Sharp with the Compact Reconnaissance Imaging
Spectrometer for Mars
, on NASA’s Mars Reconnaissance Orbiter,
identified hematite in the ridge and also mapped water-related
clay and sulfate minerals in layers just above it.

Vera Rubin Ridge stands about eight stories tall, with a trough
behind it where clay minerals await. Curiosity is now near the
downhill face, which forms an impressive wall for much of the
ridge’s length of about 4 miles (6.5 kilometers).

“In this first phase of the campaign, we’re studying the
sedimentary structures in the wall,” said JPL’s Abigail
Fraeman, a Curiosity science-team member who helped plan these
observations.

This summer’s investigations also seek information about the
boundary zone between the material that makes up the ridge and
the geological unit that Curiosity has been studying since late
2014: the Murray formation of lower Mount Sharp, which holds
evidence of ancient lakes. The Murray formation has variable
levels of hematite, but whether the hematite in it and in the
ridge accumulated under similar environmental conditions is
unknown. The planned ascent route will provide access to closer
inspection of the hematite-bearing rocks.

“We want to determine the relationship between the conditions
that produced the hematite and the conditions under which the
rock layers of the ridge were deposited,” Fraeman said. “Were
they deposited by wind, or in a lake, or some other setting?
Did the hematite form while the sediments accumulated, or
later, from fluids moving through the rock?”

Deciphering the history of the ridge’s hematite may shed light
on whether the freshwater environments that deposited the
layers of the older Murray formation were turning more acidic
by the time the layers of the ridge formed. The mission also
will be watching for clues about whether a gradient in
oxidation levels was present, as that could have provided a
potential energy source for microbial life.

Terrain near the base of the ridge is rife with boulders and
sand, creating challenging conditions for navigation, as well
as opportunities to add to the mission’s studies of sand dunes
and ripples. The largest sand dunes were at lower elevations,
including a linear dune informally named “Nathan Bridges Dune”
in memory of Nathan Bridges (1966-2017), a Curiosity team
member who helped lead the mission’s dune studies.

During the first year after its landing on Aug. 5, 2012, PDT
(Aug. 6, EDT and Universal Time), the Curiosity mission
accomplished a major goal by determining that billions of years
ago, a Martian lake offered conditions that would have been
favorable for microbial life. Curiosity has since traversed
through a diversity of environments where both water and wind
have left their imprint. The upcoming exploration of Vera Rubin
Ridge and the higher clay and sulfate layers provides
opportunities to learn even more about the history and
habitability of ancient Mars. For more about Curiosity, visit:

https://mars.jpl.nasa.gov/msl

Status of Curiosity’s Drill

The rover team will not have Curiosity’s rock sampling drill
available in the first phase of studying “Vera Rubin Ridge.”
The drill feed mechanism, which moves the bit forward or back,
faulted
on Dec. 1, 2016
, and no rocks have been drilled since then.
While continuing to test possible ways to move the bit with the
drill feed mechanism, rover engineers are also now studying
alternative ways to drill. For the 15 rocks that Curiosity has
sampled with its drill so far, two stabilizer posts, one to
each side of the bit, were placed against the rock before the
bit was extended with the feed mechanism.

“We are investigating methods to drill without using the
stabilizers,” said Curiosity Deputy Project Manager Steve Lee,
of JPL. “Instead of using the feed mechanism to drive the bit
into the rock, we may be able to use motion of the arm to drive
the bit into the rock.” Adaptation in delivering the resulting
rock powder to laboratory instruments is also under study, such
as use of the arm’s soil scoop.

News Media Contact

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster@jpl.nasa.gov

Laurie Cantillo / Dwayne Brown
NASA Headquarters, Washington
202-358-1077 / 202-358-1726
laura.l.cantillo@nasa.gov / dwayne.c.brown@nasa.gov

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