* Astronomy

The grinding teeth have worn away on the rock abrasion tool of NASA's Mars Exploration Rover Spirit (after exposing interiors of five time more rock targets than its design goal of three rocks) but the tool still has useful wire bristles for brushing targets. In this image, a figure-eight-like imprint in the Martian soil marks the spot where Spirit has begun examining subsurface deposits layer by layer. The circular indentations resulted from brushing by the rock abrasion tool, one of several instruments on the rover's robotic arm. As an effective brushing tool it is now fulfilling a soil profiling experiment on a target called "Progress."


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Image credit: NASA/JPL/Cornell/USGS
This view is a mosaic of exposures taken by Spirit's microscopic imager during the rover's 830th Martian day (May 4, 2006). The total area shown is about 6 centimetres square.

The experiment is a multi-step process of carefully brushing away fine layers of soil and then using the Mössbauer and alpha particle X-ray spectrometers, microscopic imager, and panoramic camera to examine the exposed surfaces during the long Martian winter.

Sol 834

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Image from the left navigation camera acquired on Sol 834 of Spirit's mission to Gusev Crater at approximately 12:23:26 Mars local solar time.
Credit: NASA/JPL

Sol 814 to 828


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Mosaic of 33 images of McMurdo pan at Low ridge Haven.

SPIRIT UPDATE: Spirit Begins First Interplanetary Layer-by-Layer Soil Analysis - sol 828-834, May 05, 2006:

Spirit is healthy and continuing to make progress on the rover's winter campaign of scientific experiments. This week Spirit continued work on the full-colour, 360-degree "McMurdo panorama." The finished panorama will combine 27 columns of images. Scientists anticipate that Spirit will have finished collecting the first 10 of those columns by Martian day, or sol, 834 (May 8, 2006). Spirit also continued studies of two soil targets nicknamed "Progress" and "Halley."

A winter soil analysis experiment will involve a multi-step process of removing the Mössbauer spectrometer from the target, flipping the wrist joint at the end of the robotic arm to put it in a better position for exchanging tools, re-touching the target with the Mössbauer to confirm precise placement, and exchanging tools from the Mössbauer spectrometer to the rock abrasion tool. Using the brush at the end of the rock abrasion tool, Spirit will remove a layer of soil up to 1 millimetre thick. During brushing, the rover will take a movie of the procedure with the right lens of the hazard-avoidance camera. After the brushing, the rover will acquire a microscopic image of the freshly exposed surface as well as a colour image using all 13 filters of the panoramic camera. The rover will then start the process again and remove another layer of soil.

Spirit is also poised to begin a five-month, remote, photometric study of seasonal changes in surface properties of soil exposed in the rover's tracks.

As the newly arrived Mars Reconnaissance Orbiter continues the aerobraking phase of its mission (using friction from the Martian atmosphere to refine its orbit), high-frequency X-band communications directly between Spirit and Earth will not always be available. On sol 830 (May 4, 2006), NASA's Odyssey spacecraft began transmitting communications to Spirit at UHF frequencies.

Sol-by-sol summary:

Sol 828 (May 2, 2006): Spirit conducted remote sensing and completed acquisition of column 8 of the McMurdo panorama.

Sol 829: Spirit conducted a third day of Mössbauer spectrometry of the Progress soil target, for a total of 69 hours of analysis of the target with the instrument.

Sol 830: Spirit began progressive brushing of loose soil for the first time and collected microscopic images.

Sol 831: Spirit conducted remote sensing, acquired column 9 of the McMurdo pan, and completed an 18-hour analysis of Progress with the alpha particle X-ray spectrometer.

Sol 832: Plans called for Spirit to acquire microscopic images of Halley.

Sol 833: Plans called for Spirit to conduct remote sensing, acquire column 10 of the McMurdo pan, and complete a second 18-hour study of Progress with the alpha particle X-ray spectrometer.

Sol 834 (May 8, 2006): Plans called for Spirit to continue remote sensing studies and begin monitoring changes in surface properties of soil exposed in the rover's tracks.

Odometry:
As of sol 831 (May 5, 2006), Spirit's total odometry remained at 6,876.18 meters.