* Astronomy

Spirit moved its robotic arm on Sol 1,277 (Aug. 6) for the first time in 20 days.

 
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Credit: NASA/JPL-Caltech/Cornell

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Mars Exploration Rover Status Report: Spirit Sees Dustier Sky
As of Thursday, July 26, NASA rovers Spirit and Opportunity are both enduring levels of reduced power supply. The rovers can survive at these levels, but NASA continues to sharply restrict their activities.
Spirit is under the dustiest sky ever seen at that location. Sunlight at Spirit's location is more obscured than current conditions for Opportunity, though not as severe as what Opportunity faced a week ago.
Mission controllers Thursday received the first status report from Opportunity in three days. This delay had been planned between transmissions to minimize the rovers energy use. Energy output from Opportunity's solar panels has climbed above 200 watt hours per day (enough to run a 100 watt bulb for two hours), compared with daily levels as low as 128 watt hours last week. Light must reach the solar panels for them to provide electricity.
Opportunity has resumed measurements of how obscured the sun is. These had been suspended for several days to save power. The new measurement included in Thursday's downlink indicates slight clearing. However, some dust has freshly settled onto the solar panels, lessening the increase in power output.

"We are still waiting out the storms, and we don't know how long they will last or how bad they will get" - John Callas, rover project manager at NASA's Jet Propulsion Laboratory, Pasadena, California.

Each rover has eight radioisotope heater units that supplement electric heaters for keeping batteries and electronics within their operating temperature ranges. The radioisotope heater units use the decay heat from plutonium-238. Each of them provides about one watt of heat. They aid the rovers' survival on very low-power days and through cold nights, though the electric heaters are also necessary.
Controllers are keeping Opportunity on an extremely low-power-use plan under which the rover transmits information to Earth only once every three days. A heater switch that has been stuck in the on position since landing day makes Opportunity more vulnerable to low power than Spirit. Spirit has suspended most activities, but is still communicating daily.

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SPIRIT UPDATE: Spirit Examines Rocks Possibly Formed In Volcanic Gases or Hot Springs - sol 1247-1252, July 16, 2007:

Spirit is healthy after driving to a cluster of rock fragments known as "Innocent Bystander" (so named because Spirit accidentally ran over it when another rock, "Virginia Bell," was the intended target. The aim had been to crush Virginia Bell to expose a fresh surface for examination).
It was a fortuitous encounter, though, because indications are that Innocent Bystander may have been formed by either a fumarole or hot spring. A fumarole is a vent in the Earth's surface that emits steam and volcanic gases. Volcanic gases leach the original rock and leave silica-rich rock behind. If Innocent Bystander was created in a hot spring environment, then it could be siliceous sinter, a kind of silica-rich rock that precipitates directly from water.
Spirit had a solar-array dust-cleaning event on the rover's 1,252nd day, or sol, of Martian exploration (July 12, 2007). Even though Tau, a measurement of atmospheric opacity caused by dust, has been trending upward for the past several days, Spirit's solar power levels have risen slightly due to wind-related cleaning of the solar panels.

Sol-by-sol summary:
In addition to daily remote science observations of the atmosphere and terrain using the panoramic camera and the miniature thermal emission spectrometer, and communication activities including morning direct-from-Earth uplinks via the rover's high-gain antenna and evening downlinks at UHF frequencies via the Mars Odyssey orbiter, Spirit completed the following activities:

Sol 1247 (July 6, 2007): Spirit monitored atmospheric dust with the panoramic camera, scanned the sky and ground with the miniature thermal emission spectrometer, stowed the robotic arm, and drove to Innocent Bystander. Along the way, Spirit acquired mid-drive, full-colour images of the work volume using all 13 filters of the panoramic camera as well as images with the hazard avoidance cameras. After transmitting data to the Odyssey orbiter, Spirit again measured atmospheric dust and took images of the sun with the navigation camera.

Sol 1248: In the morning, Spirit monitored atmospheric dust and surveyed the horizon with the panoramic camera, monitored dust on the rover mast, and acquired thumbnail images of the sky. Spirit then continued to measure atmospheric dust and scan the sky and ground with the miniature thermal emission spectrometer. The rover completed a calibration of the miniature thermal emission spectrometer as well as a survey of the sky and ground with the instrument. Spirit completed a survey at high Sun with the panoramic camera. After communicating with the Odyssey spacecraft, Spirit measured atmospheric dust.

Sol 1249: In the morning, Spirit monitored atmospheric dust with the panoramic camera, watched for dust devils, and acquired movie frames of potential dust devils with the navigation camera. Spirit continued to measure atmospheric dust opacity with the panoramic camera and scan the sky and ground with the miniature thermal emission spectrometer. After the uplink to the Odyssey orbiter, Spirit continued to measure atmospheric opacity with the panoramic camera.

Sol 1250: In the morning, Spirit measured atmospheric opacity with the panoramic camera and surveyed the sky and ground with the miniature thermal emission spectrometer. Spirit checked for drift (changes with time) in the miniature thermal emission spectrometer. Spirit drove closer to Innocent Bystander and acquired post-drive images with the hazard avoidance cameras and a 360-degree panorama with the navigation camera. The rover continued to measure atmospheric opacity with the panoramic camera and scan the sky and ground with the miniature thermal emission spectrometer. After communicating with Odyssey, Spirit acquired navigation camera images of the Sun and again monitored atmospheric dust with the panoramic camera.

Sol 1238: In the morning, Spirit monitored dust build-up on the rover's mast, surveyed the horizon with the panoramic camera, and acquired movie frames with the navigation camera in search of dust devils. Spirit acquired microscopic images of the solar arrays, capture magnet, and filter magnet to document dust levels since the most recent dust-cleaning events on sols 1233 and 1234 (June 22-23, 2007). The rover acquired microscopic images of Eileen Dean and collected data on the target using the alpha-particle X-ray spectrometer. Spirit acquired four sets of comparative measurements with the miniature thermal emission spectrometer early in the day, in the afternoon, overnight, and early the next sol. Spirit observed the Sun with the navigation camera in support of the Mars Science Laboratory rover scheduled for launch in 2009. The goal of these observations is to see if navigation camera images of the sun can be used to orient the rover.

Sol 1251: Upon awakening, Spirit acquired images of the Sun using the navigation camera, measured atmospheric opacity with the panoramic camera, completed a survey of clasts using the panoramic camera, and surveyed the sky and ground with the miniature thermal emission spectrometer. Spirit continued to monitor atmospheric dust and scan the surroundings, then unstowed the robotic arm and acquired a 2x1x7 mosaic of microscopic images of Innocent Bystander. Spirit placed the alpha-particle X-ray spectrometer on Innocent Bystander, measured atmospheric dust and completed a survey at high Sun with the panoramic camera, and continued to monitor atmospheric dust and survey the surroundings. Spirit acquired thumbnail images of the sky using the panoramic camera, measured late atmospheric dust opacity, and scanned the calibration target and surveyed the sky and ground with the miniature thermal emission spectrometer. Spirit took a nap and awoke at 11:10 p.m. local Mars time to begin an alpha-particle X-ray study that was to last just under 12 hours.

Sol 1252 (July 12, 2007): After solar array wakeup, Spirit was slated to continue measuring atmospheric opacity with the panoramic camera, acquire images of the Sun with the navigation camera, and survey the sky and ground with the miniature thermal emission spectrometer.

Odometry:
As of sol 1250 (July 10, 2007), Spirit's total odometry remained at 7,153 metres.

This image was taken by the Spirit rover on Sol 1252.


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Credit NASA