NASA Curiosity Mars Rover Checks Odd-looking Iron Meteorite.
On Mars, NASA's
Curiosity rover zapped a globular, golf-ball-size object with a laser, and the
signal it got back confirmed it was an iron-nickel meteorite fallen from the
Red Planet's sky.
From the NASA announcement:
Iron-nickel meteorites are a common class of space
rocks found on Earth, and previous examples have been seen on Mars, but this
one, called "Egg Rock," is the first on Mars examined with a
laser-firing spectrometer. To do so, the rover team used Curiosity's Chemistry
and Camera (ChemCam) instrument.
Scientists of the Mars Science Laboratory (MSL) project, which
operates the rover, first noticed the odd-looking rock in images taken by
Curiosity's Mast Camera (Mastcam) at at a site the rover reached by an Oct. 27
drive.
"The dark, smooth and lustrous aspect of this target, and
its sort of spherical shape attracted the attention of some MSL scientists when
we received the Mastcam images at the new location," said ChemCam team
member Pierre-Yves Meslin, at the Research Institute in Astrophysics and
Planetology (IRAP), of France's National Center for Scientific Research (CNRS)
and the University of Toulouse, France.
ChemCam found iron, nickel and phosphorus, plus lesser
ingredients, in concentrations still being determined through analysis of the
spectrum of light produced from dozens of laser pulses at nine spots on the
object. The enrichment in both nickel and phosphorus at some of the same points
suggests the presence of an iron-nickel-phosphide mineral that is rare except
in iron-nickel meteorites, Meslin said.
Iron meteorites typically originate as core material of
asteroids that melt, allowing the molten metal fraction of the asteroid's
composition to sink to the center and form a core.
"Iron meteorites provide records of many different
asteroids that broke up, with fragments of their cores ending up on Earth and
on Mars," said ChemCam team member Horton Newsom of the University of New
Mexico, Albuquerque. "Mars may have sampled a different population of
asteroids than Earth has."
In addition, the study of iron meteorites found on Mars --
including examples found previously by Mars rovers -- can provide information
about how long exposure to the Martian environment has affected them, in comparison
with how Earth's environment affects iron meteorites. Egg Rock may have fallen
to the surface of Mars many millions of years ago. Researchers will be
analyzing the ChemCam data from the first few laser shots at each target point
and data from subsequent shots at the same point, to compare surface versus
interior chemistry.
Egg Rock was found along the rover's path up a layer of lower
Mount Sharp called the Murray formation, where sedimentary rocks hold records
of ancient lakebed environments on Mars. The main science goal for Curiosity's
second extended mission, which began last month, is to investigate how ancient
environmental conditions changed over time. The mission has already determined
that this region once offered conditons favorable for microbial life, if any
life ever existed on Mars.
Curiosity was launched five years ago this month, on Nov. 26,
2011, from Cape Canaveral Air Force Station, Florida. It landed inside Gale
Crater, near the foot of Mount Sharp, in August 2012.
The rover remains in good condition for continuing its
investigations, after working more than twice as long as its originally planned
prime mission of about 23 months, though two of its 10 science instruments have
recently shown signs of potentially reduced capability. The neutron-generating
component of Curiosity's Dynamic Albedo of Neutrons (DAN) instrument, designed
for working through the prime mission, is returning data showing reduced
voltage. Even if DAN could no longer generate neutrons, the instrument could
continue to check for water molecules in the ground by using its passive mode.
The performance of the wind-sensing capability from Curiosity's Rover
Environmental Monitoring Station (REMS) is also changing, though that
instrument still returns other Mars-weather data daily, such as temperatures,
humidity and pressure. Analysis is in progress for fuller diagnosis of unusual
data from DAN, which was provided by Russia, and REMS, provided by Spain.
The U.S. Department of Energy's Los Alamos National Laboratory
in Los Alamos, New Mexico, developed ChemCam in partnership with scientists and
engineers funded by the French national space agency (CNES). Mastcam was built
by Malin Space Science Systems, San Diego. NASA's Jet Propulsion Laboratory, a
division of Caltech in Pasadena, California, manages the Mars Science
Laboratory Project for the NASA Science MIssion Directorate, Washington, and
built the project's Curiosity rover.
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