[meteorite-list] Mars Exploration Rovers Update: May 15-20, 2009

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 27 May 2009 17:50:59 -0700 (PDT)
Message-ID: <200905280050.RAA07218_at_zagami.jpl.nasa.gov>

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

SPIRIT UPDATE: Spirit Works on Exit Strategy - sols 1907-1912,
May 15-20, 2009

Rover team members continue their recovery strategy to extricate Spirit
from the loose, soft terrain on the west side of "Home Plate." The rover
continues to conduct extensive remote sensing observations of the local
terrain.

With the extra energy Spirit has gained from recent solar array dust
cleaning events, morning UHF relay passes have been added. A low-voltage
continuity test of the motor on the left middle wheel was performed on
Sol 1908 (May 16, 2009). The results showed normal resistance for a
healthy motor. Even though very small voltages were used in that test, a
tiny amount of motion (less than a degree) was observed. This is not
unexpected, as the motion was opposite of the apparent jam from Sol 1899
(May 6, 2009) and is likely due to the unwinding (relaxation) of the
strain in the 1500:1 gearbox. The small motion means it is now less
likely there is a jam in the gearbox. A small 4-degree backward wheel
motion test is planned for Sol 1913 (May 21, 2009) to investigate the
wheel further.

On the ground, work continues on the preparation of the sandbox at JPL
to recreate the terrain and conditions of the rover on Mars. A "shoebox"
test of a soil simulant, called Bag House dust (a ground basaltic
cinder), will be performed under one wheel of the surface system testbed
(SSTB) rover to see if the simulant exhibits the characteristics of the
soil on Mars. However, testing with the SSTB rover at JPL is held up due
to a computer server disk crash. That server loss is being remedied, but
will take some time.

As of Sol 1912 (May 20, 2009), solar-array energy production was 716
watt-hours, with atmospheric opacity (tau) around 0.628 and the dust
factor improved to 0.680. Spirit has been responsive and communicative,
with no reoccurrence of the anomalies from 30 sols ago.

As of Sol 1912 (May 20, 2009), Spirit's total odometry remains 7,729.93
meters (4.8 miles).

------------------------------------------------------------------------

OPPORTUNITY UPDATE: Opportunity Images Belly Pan to Help Spirit -
sols 1886-1892, May 14-20, 2009:

This week, Opportunity completed in-situ (contact) science with her
robotic arm (IDD) on small pebbles located on an exposed rock outcrop.

On Sol 1886 (May 14, 2009), Opportunity collected a 5-stack of
Microscopic Imager pictures then placed the Alpha Particle X-Ray
Spectrometer on the target "Kasos." On the next sol, the rover placed
the Moessbauer spectrometer on the same target for a multi-sol integration.

On Sol 1890 (May 18), Opportunity did something special to help out
Spirit. The rover tested the technique of using the Microscopic Imager
on the end of the IDD to image underneath the rover's belly pan,
specifically examining her left middle and right middle wheels. Although
the short-focus Microscopic Imager was never designed for such imaging,
the images are of very good quality and show a fair amount of detail.
Now that we know this technique can work, it may be tried on Spirit to
determine if the rover is, in fact, high-centered on some rocks and to
see if any obstruction of the left middle wheel can be observed.

With her in-situ work complete, Opportunity then drove about 20 meters
(.01 miles) on Sol 1891 (May 19). A slight trend upward in the motor
current for the right front wheel was noted. On Sol 1992 (May 20),
Opportunity drove about 74 meters (243 feet), passing another milestone.

As of Sol 1891(May 19), Opportunity's solar-array energy production was
461 watt-hours, the atmospheric opacity (tau) remains around 0.613 and
the dust factor is 0.557. Opportunity's total odometry as of Sol 1892
(May 20, 2009) is 16,003.33 meters (9.94 miles).
Received on Wed 27 May 2009 08:50:59 PM PDT