* Astronomy

OPPORTUNITY UPDATE: Digging Out of the Dune - sol 833-837, June 1, 2006:

Opportunity is less than a kilometre from "Victoria Crater." During the last planned drive on sol 833, the rover became embedded in a soft dune. As designed, the drive was stopped by a slip check. The extraction process began on sol 836, with 5 meters of commanded motion, and 9 centimetres of actual forward progress. The results are encouraging, and extraction will continue on Friday (June 2, 2006) and over the weekend if necessary. Opportunity is otherwise healthy and continues to conduct atmospheric and targeted remote sensing on the path south.

Sol-by-sol summaries:

Sol 833 (May 28, 2006): For this sol, the team planned a drive of about 30 meters, post-drive imaging, and atmospheric remote sensing. The drive started with a small turn in place to move to the centre of a dune trough. The material the rover is in is soft, and the rover experienced very high rates of slippage. A slip check precluded further driving.

Sol 834: On this second sol of a two-sol plan, Opportunity performed some atmospheric remote sensing (including cloud imaging) and recharged the batteries.

Sol 835: Opportunity took a break from driving and collected high-resolution images to better characterize the material in which the rover is embedded.

Sol 836: After evaluating the tracks and soil, the team began the extraction process. Five meters of driving was commanded, with limits imposed on rover tilt, mobility suspension angles, pitch, yaw, and total distance traversed. The drive resulted in 9 centimetres of forward progress. This is more than three times the rate of progress experienced during the "Purgatory Dune" extraction in April and May 2005. Hazard avoidance camera images also show that the front cleats are not as caked as during the Purgatory extraction.

Sol 837 (June 1): Plans called for the dune extraction to continue on this sol, with 10 meters of commanded motion. The sol 836 mobility safety checks were used. In addition, the allowable yaw range was narrowed, and the drive sequence also imposed a new limit for maximum visual odometry failures. Since visual odometry is likely to fail if more than expected progress is made, this will prevent the rover from travelling too far if it should happen to break free of the dune.

As of sol 836, Opportunity's total odometry is 7971.42 metres.

Right Panoramic Camera Non-linearised Full frame EDR acquired on Sol 833 of Opportunity's mission to Meridiani Planum at approximately 12:44:10 Mars local solar time, camera commanded to use Filter 2 (754 nm).



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Credit NASA/JPL/Cornell

OPPORTUNITY UPDATE: Checking Out 'Cheyenne' and Testing Relay for Phoenix - sol 818-824, May 23, 2006:

Opportunity is healthy and continuing to make its way toward "Victoria Crater." Opportunity made 108 metres of progress in two sols of driving and was approximately 1,000 metres from Victoria Crater at the end of Sol 823.

Opportunity and NASA's Mars Odyssey orbiter are conducting a set of demonstrations using the relay between the rover and orbiter to aid planning for communications during NASA's Phoenix Mars Lander mission, slated for launch in August 2007 and landing in May 2008.

Sol-by-sol summaries:

Sol 818 (May 13, 2006): Opportunity investigated a rock target called "Cheyenne." It used the microscopic imager to examine the target, then used the rock abrasion tool's wire bristles to brush the target. After the brushing, the alpha particle X-ray spectrometer collected data about what elements make up the rock. The rover also took images with the panoramic camera for a mosaic view from the location reached by Sol 817's drive.

Sol 819: Opportunity took a post-brush microscopic stereo image mosaic of Cheyenne and evaluated the target's mineral composition with the Mössbauer spectrometer. The rover also took a panoramic-camera image of "Pueblo," an area of layered outcrop.

Sol 820: Opportunity used its Mössbauer spectrometer on Cheyenne, observed the sky and ground with the miniature thermal emission spectrometer, and used the navigation camera to check for clouds.

Sol 821: The rover took images of Cheyenne using the 13 filters of the panoramic camera. Then it drove about 36.64 metres and took pictures from the new location with the navigation camera and the panoramic camera. It also used the panoramic camera for observing the sky.

Sol 822: Opportunity used its navigation camera to do rearward-looking imaging and cloud scans. The rover also used its miniature thermal emission spectrometer to observe the sky and ground, and it worked with Odyssey to conduct the second part of the Phoenix relay test. (The first part was on Sol 812.)

Sol 823: Opportunity drove 71.2 metres then took images from the new location with the navigation camera and the panoramic camera. The rover also used the panoramic camera to evaluate the clarity of the atmosphere, monitor dust on the camera mast and observe the sky.

Sol 824 (May 19, 2006): On this sol, Opportunity took rearward-looking images with its navigation camera, observed the ground and sky with its miniature thermal emission spectrometer, and assessed atmospheric clarity with its panoramic camera. During the sol's relay pass with Odyssey, the rover used the miniature thermal emission spectrometer again to observe the sky and ground.

Opportunity's total odometry as of Sol 821 (May 16, 2006) was 7,829.99 metres.

Sol 824



Right Navigation Camera Non-linearised Full frame EDR acquired on Sol 824 of Opportunity's mission to Meridiani Planum at approximately 12:03:51 Mars local solar time.
Credit NASA/JPL