[meteorite-list] Mars Sliding Behind Sun After Rover Anniversary

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 20 Jan 2011 17:43:48 -0800 (PST)
Message-ID: <201101210143.p0L1hmLn020100_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2011-022

Mars Sliding Behind Sun After Rover Anniversary
Jet Propulsion Laboratory
January 20, 2011


Mars Exploration Rover Mission Status Report

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 Earth's perspective.

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.

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

2011-022
Received on Thu 20 Jan 2011 08:43:48 PM PST