[meteorite-list] Mars Exploration Rovers Update - November 13-20, 2008

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 1 Dec 2008 16:33:09 -0800 (PST)
Message-ID: <200812020033.QAA05234_at_zagami.jpl.nasa.gov>

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

SPIRIT UPDATE: Serious but Stable - sol 1730-1736,
November 14 - November 20, 2008:

Spirit's condition has improved during the past week, though skies
remain fairly dusty after the recent Martian dust storm. Since sol 1730
(Nov. 14, 2008), solar-array energy has averaged 169 watt-hours (100
watt-hours is the amount of energy needed to light a 100-watt bulb for 1
hour). The latest measurement of atmospheric darkness caused by dust,
known as Tau, is 0.858. The dust factor, representing the portion of
sunlight penetrating the coating of dust on the solar panels, is 0.2912.

Spirit performed a cursory check of the health of the miniature thermal
emission spectrometer. After three nights with the spectrometer's
heaters disabled, the instrument appeared to be undamaged as of sol
1730. Power is not yet sufficient to re-enable those heaters, though
Spirit will continue to monitor the spectrometer while waiting for power
to improve. For the most part, Spirit is limiting activities to those
necessary for maintaining engineering health and safety.

Spirit endured another challenge when new commands from Earth for sol
1734 (Nov. 18, 2008) did not arrive. At that point, Spirit began to
execute a backup set of activities known as a runout plan. On Earth,
engineers created a new sequence of commands for sol 1736 (Nov. 20,
2008) to manage communications and preserve power. Meanwhile, they are
investigating why Spirit did not receive their previous commands.

According to the latest Martian weather report for Nov. 15 (sol 1731),
skies are expected to continue to clear during the next couple of weeks.
No other storms have been identified within a couple of thousand
kilometers of Spirit's location.

Spirit is preparing for solar conjunction, where the Sun is between
Earth and Mars, preventing communications. This period begins Nov. 29th.
Before and during solar conjunction, Spirit's activities will remain
conservative as the rover waits for the skies to clear and for the power
situation to improve.

Sol-by-sol summary

In addition to measuring dust-related changes in atmospheric opacity
with the panoramic camera, Spirit completed the following activities:

Sol 1730 (Nov. 14, 2008): Spirit observed the sky briefly with the
miniature thermal emission spectrometer.

Sol 1731: Spirit rested and soaked up the Sun's rays to recharge the
batteries.

Sol 1732: Spirit rested and soaked up the Sun's rays to recharge the
batteries.

Sol 1733: Spirit rested and soaked up the Sun's rays to recharge the
batteries.

Sol 1734: Spirit completed basic activities in the runout plan.

Sol 1735: Spirit completed basic activities in the runout plan.

Sol 1736 (Nov. 20, 2008): Spirit completed basic activities in the
runout plan.

Odometry:

As of sol 1736 (Nov. 20, 2008), Spirits total odometry was 7,529.02
meters (4.68 miles).

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

OPPORTUNITY UPDATE: Opportunity Prepares for Two Weeks of Independent
Study - sol 1709-1715, November 13-19, 2008:

Opportunity is getting ready for solar conjunction, the time when the
Sun is in the line of sight between Earth and Mars. During this two-week
period, from Nov. 30, 2008 to Dec. 13, 2008, the mission team will not
send new commands to the rover. The science team plans to position
Opportunity on a rock outcrop, possibly near a cobble the rover can
study with the Moessbauer spectrometer, during this time interval.

Opportunity began the week with a 93-meter (310-foot) drive on Sol 1709
(Nov. 13, 2008). The drive allowed the rover to reach a large expanse of
bare outcrop. Another drive on Sol 1710 (Nov. 14, 2008), covering 17
meters (56 feet), placed the rover near potential targets of scientific
interest. A candidate target, a cobble about 8 meters (30 feet) away,
became the objective of the drive on Sol 1713 (Nov. 17, 2008). The
8-meter drive positioned the cobble, now nicknamed "Santorini", within
the work volume of the science instruments on Opportunity's robotic arm.

The challenge for the team was the placement of the science instruments
on Santorini using only 4 degrees of freedom of the robotic arm instead
of the usual 6. The rover is not able to change the azimuth of the
shoulder joint, that is, move it from side to side, because the shoulder
azimuth joint (Joint 1) is disabled due to degraded performance.

On Sol 1714 (Nov. 18, 2008), Opportunity successfully placed the
Moessbauer spectrometer on a faceted surface of the cobble. The contact
switches on the instrument confirmed that the spectrometer had touched
the surface. An analysis by the spectrometer is now under way. Rover
operators plan to have Opportunity integrate Moessbauer measurements of
Santorini for the two-week period of solar conjunction.

Opportunity is acquiring a panorama of images using multiple filters of
the panoramic camera and making daily observations of atmospheric dust
as well as measuring atmospheric argon using the alpha-particle X-ray
spectrometer APXS. The rover is creating occasional, time-lapse movies
of clouds with the navigation camera.

This coming weekend, engineers plan another attempt to remove dust from
the miniature thermal emission spectrometer mirror by shaking it.

As of Sol 1715 (Nov. 29, 2008), the solar array energy was 565
watt-hours (100 watt-hours is the amount of energy needed to light a
100-watt bulb for one hour). The atmospheric opacity (tau) was 0.747 and
the dust factor (a measure of sunlight-blocking dust on the solar
arrays) was 0.694.

Sol-by-sol summary

In addition to measuring dust-related changes in atmospheric clarity
with the panoramic camera and relaying data from Mars to NASA's Odyssey
orbiter for transmission to Earth, Opportunity completed the following
activities:

Sol 1709 (Nov. 13, 2008): Opportunity drove 93 meters (300 feet) toward
outcrop, made atmospheric observations with the panoramic camera,
acquired targeted images with the panoramic and navigation cameras, and
measured argon gas in the atmosphere with the alpha-particle X-ray
spectrometer.

Sol 1710: Opportunity drove 17 meters (56 feet) on outcrop, made
atmospheric observations with the panoramic camera, acquired targeted
images with the panoramic and navigation cameras, and measured argon gas
in the atmosphere with the alpha-particle X-ray spectrometer.

Sol 1711: Opportunity completed atmospheric observations with the
panoramic camera, acquired targeted images with the panoramic camera,
and measured atmospheric argon with the alpha-particle X-ray spectrometer.

Sol 1712: Opportunity completed atmospheric observations with the
panoramic camera, measured atmospheric argon with the alpha-particle
X-ray spectrometer, and acquired navigation-camera images for a
time-lapse movie in search of clouds.

Sol 1713: Opportunity drove 8 meters (30 feet) toward Santorini, made
atmospheric observations with the panoramic camera, and acquired
navigation-camera images for a time-lapse movie in search of clouds.

Sol 1714: Opportunity placed the Moessbauer spectrometer on Santorini,
integrated measurements of the cobble with the spectrometer, and
acquired targeted images and studied the atmosphere with the panoramic
camera.

Sol 1715 (Nov. 19, 2008): Opportunity continued the integration of data
from Santorini with the alpha-particle X-ray spectrometer, acquired
panoramic-camera images of multiple targets, and used the camera to make
atmospheric observations.

Odometry

As of sol 1715 (Nov. 19, 2008), Opportunity's total odometry was
13,616.47 meters (8.46 miles).
Received on Mon 01 Dec 2008 07:33:09 PM PST