* Astronomy

Title: The event that produced heat shield rock and its implications for the Martian atmosphere
Authors: J. E. Chappelow. V. L. Sharpton

Methods developed in previous work were used to estimate the mass, trajectory, and atmospheric conditions that produced Heat Shield Rock, the iron meteorite discovered on Mars by the Opportunity rover in January, 2005. We find that Heat Shield Rock encountered Mars at high speed and shallow entry angle, probably at a time when the planet possessed a thicker atmosphere. It entered the atmosphere with a mass of more than 60 kg, underwent significant ablation during atmospheric passage, and ricocheted across the surface upon impact. We conclude that Heat Shield Rock probably represents physical evidence that Mars once had a denser atmosphere.

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Image of Cape Verde taken by the Opportunity rover on Oct 3, 2006 (Sol 957)


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The Mars Rover Opportunity is beginning complex and dangerous science operations 242 million mi. from Earth at the massive Victoria crater, the most spectacular and potentially significant target of the entire $800-million twin-rover Mars surface exploration mission.

"We are frankly feeling a little overwhelmed by what we see so far" - Steve Squyres, rover principal investigator on his Cornell University web site.

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OPPORTUNITY UPDATE: A View Worth Waiting For! - sol 947-953, September 29, 2006:

Opportunity is healthy and sitting at the rim of "Victoria Crater"! After travelling 9,279.34 metres in 952 sols the team is rewarded by some of the most spectacular views seen on this mission. The week began with a checkout of basic mobility functions using the new flight software: arc, turn, go-to-waypoint and visual odometry. Also checked were a few of the mobility test criteria such as the time-of-day limits, suspension limits and a new capability for keep-out zones (areas deemed too dangerous to rove). Later in the week, Opportunity drove 60.1 metres over three sols to our current location at the top of "Duck Bay."

Sol-by-sol summaries:

Sol 947 (Sept. 22, 2006): Opportunity's panoramic camera took 13-filter, quarter-frame images of the targets "Macaroni" and "Rockhopper," and a mosaic of images of "Kitty Clyde's Sister." During the afternoon communication-relay pass by NASA's Mars Odyssey orbiter, the miniature thermal emission spectrometer was used to evaluate Macaroni and Rockhopper. The navigation camera checked for clouds and the panoramic camera assessed the clarity of the atmosphere with a tau measurement.

Sol 948: The morning of this sol, the rover monitored dust buildup and targeted the sky and ground with its miniature thermal emission spectrometer. Opportunity executed a series of mobility tests to check out the new version of its flight software. Post-drive imaging included 360-degree view by the navigation camera and an image mosaic by the panoramic camera.

Sol 949: In the morning of this sol, the panoramic camera imaged the sky and measured for atmospheric clarity. The navigation camera looked for clouds and the miniature thermal emission spectrometer did a sky and ground measurement. This sol contained un-targeted remote sensing because it was the third of a three-sol plan. The panoramic camera continued to be busy, taking another tau measurement and sky images. Before the Odyssey pass, the navigation camera took images of the sky (called "sky flats") for calibration purposes. During the Odyssey pass, Opportunity used its miniature thermal emission spectrometer.

Sol 950: Opportunity used part of the morning block of this sol to take a panoramic camera tau measurement and to look for clouds with its navigation camera. It also shot images of the sky with the panoramic camera and observed the sky and ground with its miniature thermal emission spectrometer. The rover completed another panoramic camera tau measurement before it drove 30.2 metres toward Victoria Crater's rim. Post-drive imaging included hazard avoidance camera imaging, a panoramic camera mosaic and a navigation camera 360-degree image.

Sol 951: This morning, Opportunity used its panoramic camera to survey the sky. The rover then took a panoramic camera tau measurement, drove 26.4 metres toward Duck Bay and completed post-drive imaging, including navigation and panoramic camera mosaics. The navigation camera looked for clouds and the panoramic camera imaged the sky.

Sol 952: Opportunity used its miniature thermal emission spectrometer to measure the sky and ground. The rover took pre-drive panoramic camera and navigation camera images. Opportunity drove 3.5 metres toward the rim's edge, then took a navigation camera mosaic. There was a post-drive navigation camera cloud observation before the rover shut down for the afternoon. Before the Odyssey pass, the panoramic camera made a tau measurement and the miniature thermal emission spectrometer measured the sky and ground during the orbiter's pass. The panoramic camera took a sunset tau measurement.

Sol 953 (Sept. 29, 2006): In the morning of this sol, the panoramic camera imaged the sky, the navigation camera looked for clouds and the miniature thermal emission spectrometer measured the sky and ground. This sol is the first of two sols of targeted remote sensing in Duck Bay before Opportunity will drive off to "Cape Verde." The rover is at its closest approach to Victoria Crater and it has an incredible view! The plan for the remainder of this sol is to: take a panoramic camera tau measurement, look for clouds with the navigation camera, take a navigation camera mosaic in the drive direction, and take part one of a large panoramic camera panorama. The miniature thermal emission spectrometer will take a vertical scan of "Cabo Frio" during the Odyssey pass. The plan also calls for another navigation camera scan for clouds and a panoramic camera 13-filter examination of Cabo Frio to support the miniature thermal emission spectrometer in the morning of sol 954.

As of sol 952 (Sept. 27, 2006), Opportunity's total odometry is 9,279.34 metres.