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| The drive by NASA's Mars rover Curiosity during the mission's 43rd Martian day, or sol, (Sept. 19, 2012) ended with this rock about 8 feet (2.5 meters) in front of the rover. Image credit: NASA/JPL-Caltech |
NASA's Mars rover Curiosity has driven up to a
football-size rock that will be the first for the rover's arm to examine.
Curiosity is about 8 feet (2.5 meters) from the rock. It
lies about halfway from the rover's landing site, Bradbury Landing, to a
location called Glenelg. In coming days, the team plans to touch the rock with
a spectrometer to determine its elemental composition and use an arm-mounted
camera to take close-up photographs.
Both the arm-mounted Alpha Particle X-Ray Spectrometer
and the mast-mounted, laser-zapping Chemistry and Camera Instrument will be
used for identifying elements in the rock. This will allow cross-checking of
the two instruments.
The rock has been named "Jake Matijevic." Jacob
Matijevic (mah-TEE-uh-vik) was the surface operations systems chief engineer
for Mars Science Laboratory and the project's Curiosity rover. He passed away
Aug. 20, at age 64. Matijevic also was a leading engineer for all of the
previous NASA Mars rovers: Sojourner, Spirit and Opportunity.
Curiosity now has driven six days in a row. Daily
distances range from 72 feet to 121 feet (22 meters to 37 meters).
"This robot was built to rove, and the team is
really getting a good rhythm of driving day after day when that's the priority,"
said Mars Science Laboratory Project Manager Richard Cook of NASA's Jet
Propulsion Laboratory in Pasadena, Calif.
The team plans to choose a rock in the Glenelg area for
the rover's first use of its capability to analyze powder drilled from
interiors of rocks. Three types of terrain intersect in the Glenelg area -- one
lighter-toned and another more cratered than the terrain Curiosity currently is
crossing. The light-toned area is of special interest because it retains
daytime heat long into the night, suggesting an unusual composition.
"As we're getting closer to the light-toned area, we
see thin, dark bands of unknown origin," said Mars Science Laboratory
Project Scientist John Grotzinger of the California Institute of Technology,
Pasadena. "The smaller-scale diversity is becoming more evident as we get
closer, providing more potential targets for investigation."
Researchers are using Curiosity's Mast Camera (Mastcam)
to find potential targets on the ground. Recent new images from the rover's
camera reveal dark streaks on rocks in the Glenelg area that have increased
researchers' interest in the area. In addition to taking ground images, the
camera also has been busy looking upward.
On two recent days, Curiosity pointed the Mastcam at the
sun and recorded images of Mars' two moons, Phobos and Deimos, passing in front
of the sun from the rover's point of view. Results of these transit
observations are part of a long-term study of changes in the moons' orbits.
NASA's twin Mars Exploration Rovers, Spirit and Opportunity, which arrived at
Mars in 2004, also have observed solar transits by Mars' moons. Opportunity is
doing so again this week.
"Phobos is in an orbit very slowly getting closer to
Mars, and Deimos is in an orbit very slowly getting farther from Mars,"
said Curiosity's science team co-investigator Mark Lemmon of Texas A&M
University, College Station. "These observations help us reduce
uncertainty in calculations of the changes."
In Curiosity's observations of Phobos this week, the time
when the edge of the moon began overlapping the disc of the sun was predictable
to within a few seconds. Uncertainty in timing is because Mars' interior
structure isn't fully understood.
Phobos causes small changes to the shape of Mars in the
same way Earth's moon raises tides. The changes to Mars' shape depend on the
Martian interior which, in turn, cause Phobos' orbit to decay. Timing the
orbital change more precisely provides information about Mars' interior
structure.
During Curiosity's two-year prime mission, researchers
will use the rover's 10 science instruments to assess whether the selected
field site inside Gale Crater ever has offered environmental conditions
favorable for microbial life.
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