NASA’s senior Mars rover, Opportunity, has just passed the shortest-daylight weeks of the long Martian year with its solar panels in encouragingly clean condition for entering a potential dust-storm season in 2018.
Before dust season will come the 14th Earth-year anniversaries of Mars landings by the twin rovers Spirit and Opportunity in January 2004. Their missions were scheduled to last 90 Martian days, or sols, equivalent to about three months.
“I didn’t start working on this project until about Sol 300, and I was told not to get too settled in because Spirit and Opportunity probably wouldn’t make it through that first Martian winter,” recalls Jennifer Herman, power subsystem operations team lead for Opportunity at NASA’s Jet Propulsion Laboratory in Pasadena, California. “Now, Opportunity has made it through the worst part of its eighth Martian winter.” (…)
Both Opportunity and Spirit are in Mars’ southern hemisphere, where the Sun appears in the northern sky during fall and winter, so solar-array output is enhanced by tilting the rover northward. Spirit could not maintain enough energy to survive through its fourth Martian winter, in 2009, after losing use of two wheels, long past their planned lifetime. It became unable to maneuver out of a sand trap to the favorable northward tilt.
Opportunity’s current exploration of fluid-carved “Perseverance Valley” positioned it well for working productively through late fall and early winter this year. The rover has used stops at energy-favorable locations to inspect local rocks, examine the valley’s shape and image the surroundings from inside the valley.
The valley runs downhill eastward on the inner slope of the western rim of Endurance Crater, which is 14 miles (22 kilometers) in diameter. Since entering the top of the valley five months ago, Opportunity’s stops between drives have been at north-facing sites, on the south edge of the channel. The rover team calls the sites “lily pads” and plans routes from each one safely to the next, like a frog hopping from lily pad to lily pad. [More at link]