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CALIFORNIA INSTITUTE OF TECHNOLOGY
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Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif. Jan. 20, 2011
Mars Exploration Rover Mission Status Report
Mars Sliding Behind Sun After Rover Anniversary
The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/news.cfm?release=2011-022&cid=release_2011-022
PASADENA, Calif. -- The team operating NASA's Mars rover Opportunity will
temporarily suspend commanding for 16 days after the rover's seventh anniversary next
week, but the rover will stay busy.
For the fourth time since Opportunity landed on Mars on Jan. 25, 2004, Universal Time
(Jan. 24, Pacific Time), the planets' orbits will put Mars almost directly behind the sun from
During the days surrounding such an alignment, called a solar conjunction, the sun can
disrupt radio transmissions between Earth and Mars. To avoid the chance of a command
being corrupted by the sun and harming a spacecraft, NASA temporarily refrains from
sending commands from Earth to Mars spacecraft in orbit and on the surface. This year, the
commanding moratorium will be Jan. 27 to Feb. 11 for Opportunity, with similar periods
for the Mars Reconnaissance Orbiter and Mars Odyssey orbiter.
Downlinks from Mars spacecraft will continue during the conjunction period, though at a
much reduced rate. Mars-to-Earth communication does not present risk to spacecraft
safety, even if transmissions are corrupted by the sun.
NASA's Mars Reconnaissance Orbiter will scale back its observations of Mars during the
conjunction period due to reduced capability to download data to Earth and a limit on how
much can be stored onboard.
Opportunity will continue sending data daily to the Odyssey orbiter for relay to Earth.
"Overall, we expect to receive a smaller volume of daily data from Opportunity and none at
all during the deepest four days of conjunction," said Alfonso Herrera, a rover mission
manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
The rover team has developed a set of commands to be sent to Opportunity in advance so
that the rover can continue science activities during the command moratorium.
"The goal is to characterize the materials in an area that shows up with a mineralogical
signal, as seen from orbit, that's different from anywhere else Opportunity has been," said
JPL's Bruce Banerdt, project scientist for Opportunity and its rover twin, Spirit. The area is
at the southeastern edge of a crater called "Santa Maria," which Opportunity approached
from the west last month.
Drives last week brought Opportunity to the position where it will spend the conjunction
period. From that position, the rover's robotic arm can reach an outcrop target called "Luis
de Torres." The rover's Moessbauer spectrometer will be placed onto the target for several
days during the conjunction to assess the types of minerals present. The instrument uses a
small amount of radioactive cobalt-57 to elicit information from the target. With a half-life
of less than a year, the cobalt has substantially depleted during Opportunity's seven years
on Mars, so readings lasting several days are necessary now to be equivalent to much
shorter readings when the mission was newer.
Opportunity will also make atmospheric measurements during the conjunction period. After
conjunction, it will spend several more days investigating Santa Maria crater before
resuming a long-term trek toward Endurance crater, which is about 22 kilometers (14 miles)
in diameter and, at its closest edge, about 6 kilometers (4 miles) from Santa Maria.
Opportunity's drives to the southeastern edge of Santa Maria brought the total distance
driven by the rover during its seventh year on Mars to 7.4 kilometers (4.6 miles), which is
more than in any previous year. The rover's total odometry for its seventh anniversary is
26.7 kilometers (16.6 miles).
Opportunity and Spirit, which landed three weeks apart, successfully completed their
three-month prime missions in April 2004, then began years of bonus extended missions.
Both have made important discoveries about wet environments on ancient Mars that may
have been favorable for supporting microbial life. Spirit's most recent communication was
on March 22, 2010. On the possibility that Spirit may yet awaken from a low-power
hibernation status, NASA engineers continue to listen for a signal from that rover.
JPL, a division of the California Institute of Technology in Pasadena, manages the Mars
Exploration Rover project for NASA’s Science Mission Directorate, Washington.
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