[meteorite-list] Mars Exploration Rover Update: March 27 - April 02, 2008

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 10 Apr 2008 15:59:16 -0700 (PDT)
Message-ID: <200804102259.PAA28134_at_zagami.jpl.nasa.gov>

http://marsrovers.jpl.nasa.gov/mission/status.html

SPIRIT UPDATE: Spirit Advances Toward Midwinter - sol 1504-1510,
March 27 - April 02, 2008:

Seasons are about twice as long on Mars as on Earth and are offset
relative to Earth because Mars takes about twice as long to complete one
orbit around the Sun. At Spirit's location, the fall equinox -- the
start of fall, when night and day are equal in length -- arrived Dec.
12, 2007. The winter solstice -- the time of year with the shortest day
-- will arrive June 25, 2008.

Solar array energy has varied from 244 watt-hours to 256 watt-hours,
averaging 250.4 watt-hours for this period (100 watt-hours is the amount
of energy needed to light a 100-watt bulb for one hour). Tau, the
measure of atmospheric dust, has averaged 0.16, varying by only a
hundredth. The dust factor has been nearly constant at 0.35, meaning 35
percent of the sunlight reaching the arrays penetrates the dust layer to
make electricity. A low Tau is good because it means the skies are
fairly clear; a low dust factor is bad because it means the solar arrays
are coated with a fair amount of dust.

Astronomers use the symbol L(s) -- pronounced L-sub-s -- to denote how
far Mars has progressed in its orbit around the Sun. If you imagine
looking down at the solar system, with the Sun in the middle and Mars
orbiting around it, L(s) gives the location of Mars. By definition, L(s)
= 0 degrees when the Sun crosses the Martian equator. This is the first
day of Martian spring, the vernal equinox, when night and day are equal
in length, in the northern hemisphere. It's also the first day of fall,
the autumnal equinox, in the southern hemisphere. At Spirit's location
in Mars' southern hemisphere, the season is currently mid- to late fall,
and L(s) is about 55 degrees, roughly equivalent to Nov. 17 in Earth's
northern hemisphere and May 18 in Earth's southern hemisphere. L(s) will
equal 90 degrees at the time of the winter solstice.

Spirit is healthy and all subsystems are performing as expected.

Sol-by-sol summary:

To conserve energy, mission planners have restricted the number of sols
on which Spirit receives direct-from-Earth instructions via the rover's
high-gain antenna and transmits data to Earth via the Odyssey orbiter.
Spirit continues, on a daily basis, to monitor atmospheric dust levels
with the panoramic camera, check for drift (changes with time) in the
miniature thermal emission spectrometer, and survey the sky and ground
with the instrument. In addition, during the past week, Spirit completed
the following activities:

Sol 1504 (March 27, 2008): Spirit calibrated the miniature thermal
emission spectrometer and acquired a microscopic image of the capture
magnet.

Sol 1505: Upon awakening, Spirit took spot images of the sky for
calibration purposes with the panoramic camera and acquired column 6,
part 1 of the full-color "Bonestell panorama" using all 13 filters of
the panoramic camera. The rover also recharged the battery.

Sol 1506: Spirit acquired column 6, part 2 of the Bonestell panorama and
monitored dust on the panoramic-camera mast assembly. Spirit looked at
the miniature thermal emission spectrometer for calibration purposes,
acquired microscopic images of the solar panel, and acquired images of
the external magnets, which capture magnetic dust particles, using the
panoramic camera.

Sol 1507: Spirit acquired column 6, part 3 of the full-color Bonestell
panorama and recharged the battery.

Sol 1508: Spirit acquired column 7, part 1 of the full-color Bonestell
panorama and relayed data to Odyssey during the orbiter's afternoon pass
overhead.

Sol 1509: Spirit surveyed the sky at high Sun with the panoramic camera
and completed a "runout" of previously loaded activities after not being
able to receive new instructions from Earth. The rover recharged the
battery and relayed data to Odyssey.

Sol 1510: (April 2, 2008): Spirit acquired a 1-by-1-by-3 stack of
microscopic images of a soil target known informally as
"Arthur_C_Hammon" and placed the alpha-particle X-ray spectrometer on
the soil target. Plans for the following morning called for Spirit to
acquire column 7, part 2 of the full-color Bonestell panorama.

Odometry:

As of sol 1509 (April 1, 2008), Spirit's total odometry was 7,528 meters
(almost 4.7 miles).
Received on Thu 10 Apr 2008 06:59:16 PM PDT