Spirit: Regional dust storm; Opportunity: Meteorite examination continues

Although orbital observations indicate the storm is abating, the skies over Gusev crater are expected to remaining dusty for several sols. As a result, the rover team has been conservative with Spirit's planning, keeping energy consumption low and maintaining high states of charge in the batteries until the skies clear.

Spirit began the week continuing a long Mössbauer (MB) integration of the surface target "Polyphemus Eye." On Sol 2006 (Aug. 24, 2009), Sprit initiated a set of penetrometer experiments to directly measure physical properties of the embedding soil. The rock abrasion tool (RAT) was pressed into the soil at three different pre-load levels of force. The resulting indentation (soil penetration) after each pre-load was then documented with a set of images. Also on the same sol an atmospheric argon measurement was collected with the alpha particle X-ray spectrometer (APXS), and the MB was placed for another multi-sol integration.

On Earth, testing is being done with two different-weight rovers, the full-weight surface system testbed (SSTB) rover and the near Mars-weight SSTB Lite rover, in two different soil simulants. Testing with both rovers will help determine the effects of different gravity on Earth-based test results, all in preparation for the first extraction moves on Mars.

Atmospheric conditions have deteriorated owing to the large regional dust storm. As of Sol 2007 (Aug. 25, 2009), Spirit's solar-array energy production was precipitously down to 322 watt-hours, with a large increase in the atmospheric opacity (tau) to 2.61. The dust factor declined to 0.658, meaning that about 65.8 percent of the sunlight hitting the solar array penetrates through the dust on the array. Spirit's total odometry remains at 7,729.93 meters (4.80 miles).

High resolution image

This full-circle view from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Spirit shows the terrain surrounding the location called "Troy," where Spirit became embedded in soft soil during the spring of 2009. The hundreds of images combined into this view were taken beginning on the 1,906th Martian day (or sol) of Spirit's mission on Mars (May 14, 2009) and ending on Sol 1943 (June 20, 2009).

North is at the center; south at both ends. The western edge of the low plateau called Home Plate dominates the right half of the panorama. At the far right is a bright-topped mound called "Von Braun," a possible future destination for Spirit's exploration. Near the center of the panorama, in the distance, lies Husband Hill, where Spirit recorded views from the summit in 2005. The ridge on the left, near the rover tracks leading to Troy from the north, is called "Tsiolkovsky." For scale, the parallel tracks are about 1 meter (39 inches) apart. The track on the right is more evident because Spirit was driving backwards, dragging its right-front wheel, which no longer rotates.

The bright soil in the center foreground is soft material in which Spirit became embedded after the wheels on that side cut through a darker top layer. The composition of different layers in the soil at the site became the subject of intense investigation by tools on Spirit's robotic arm.

The Pancam team named this scene the camera's Calypso Panorama. This version is an approximate true-color, red-green-blue composite panorama generated from images taken through the Pancam's 750-nanometer, 530-nanometer and 480-nanometer filters. This "natural color" view is the rover team's best estimate of what the scene would look like if we were there and able to see it with our own eyes.

Credit: NASA/JPL-Caltech/Cornell University

Opportunity is continuing its contact investigation of the 70-centimeter (28-inch) meteorite called "Block Island."

On Sol 1981 (Aug. 20, 2009), the rover performed a very small rotation that moved the robotic arm (instrument deployment device, or IDD) in azimuth to reach new targets on the meteorite. On the next sol, the IDD collected a stack of microscopic imager (MI) images of new targets and then placed the alpha particle X-ray spectrometer (APXS) onto a target.

The IDD changed tools the following sol from the APXS to the Mössbauer (MB) spectrometer and placed it on the target "Siahs Swamp2" for a multi-sol integration. On Sol 1986 (Aug. 25, 2009), the MB was retracted and an ambitious MI imaging campaign, including stereo imaging, was performed on the surface of the meteorite. At the end of that, the MB was replaced for continued integration.

The shroud of the miniature thermal emission spectrometer (Mini-TES) continues to be left open on scheduled sols to allow the environment to clean putative dust contamination from the elevation mirror. No improvement in Mini-TES performance has been observed so far, but the rover has seen no wind events.

As of Sol 1986 (Aug. 25, 2009), Opportunity's solar-array energy production was 453 watt-hours with an atmospheric opacity (tau) of 0.526 and a dust factor of 0.550. The rover's total odometry was 17,229.16 meters (10.71 miles).

Source: Jet Propulsion Laboratory
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