| With
miles-high dust clouds blanketing the Martian sky, there is little
for the twin rovers to do but hunker down and wait out the worst storm
in 3 ½ years.
Opportunity is a few hundred feet from the edge of a gigantic crater that scientists hope will reveal the planet's ancient surface. On the other side of Mars, Spirit is in the same boat. "The brightness of the sun was about a third of what we normally see on a bright day," said Geoffrey Landis, a scientist at NASA's Glenn Research Center in Cleveland who helped develop the solar panels used to power the rovers. |
 NASA
Tracks left by the NASA rover Opportunity can be seen around Mars' Victoria Crater, which the solar-powered craft will soon venture into. |
The dust storm, which started in late June, now appears to be on the wane.
Opportunity pretty much shut down during the past week as summer winds whipped dust from about 1,000 miles away into a dense haze that blocked the sun.
The rover is about 262 feet from Duck Bay, the entry point to Victoria Crater, which NASA expects will reveal clues to Mars' past.
It is the largest crater either rover has faced and stretches a half-mile in diameter.
The storm also has affected the three spacecraft orbiting the planet: NASA's Mars Odyssey, the Mars Reconnaissance Orbiter and the European Space Agency's Mars Express.
But with the worst of it over, Opportunity spent the past couple of days powering up in anticipation of inching toward Victoria Crater.
In the good news department, Landis said the same winds that caused the storm appear to have cleared old dust from the solar panels, allowing them to generate power more efficiently than at any time since the landing.
When Opportunity heads into Victoria Crater, it will follow a route plotted by a team led by mapping specialist Rongxing Li of Ohio State University.
The descent will be gradual, Li said, and the rover will travel at less than its maximum pace of about 325 feet a day.
There should be plenty to see on the way down.
"The crater is a time tunnel that allows access to older material," said John Callas, project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
"The materials in the walls are in sequence, with the older materials being lower -- like in the Grand Canyon, where you can see the strata layers."
NASA hopes to get a good look at the shiny "bathtub ring" they've spotted below the rim of the crater. Scientists think the ring is the ancient surface of the planet, Callas said.
Farther down, they expect to see "blueberries" -- BB-size spheres of iron oxide that Opportunity found at lower elevations. The blue and gray spheres are of the size, shape and makeup of minerals that form in wet environments on Earth.
The rovers, which NASA expected to run for about 90 days, continue to defy all expectations.
The Mars rover program receives about $20 million in funding every year. In all, the rover project has cost $926 million.
"The materials in the walls (of the crater) are in sequence, with
the older materials being lower -- like in the Grand Canyon."
Kevin Mayhood
kmayhood@dispatch.com