The Mars Opportunity rover may soon become the first explorer to study water-carved features on Mars, but first the solar-powered robot has to survive a forecast global dust storm that could blot out the sun for days or even months.

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James Shirley, a planetary scientist at NASA’s Jet Propulsion Laboratory, believes such a storm could engulf Mars as early as Oct. 29, based on historical weather patterns.

Regional dust storms occur frequently on Mars and are large enough to be visible from Earth with telescopes. Global storms have been observed nine times since 1924, with the most recent occurring in 2007.

“Several storms will start up at once and they will blow up larger and larger until they basically cover the entire planet,” Shirley said. “They’re probably the most spectacular weather event that we can see in the solar system. I don’t think there’s really anything like it anywhere else.”

The regional dust storms tend to occur when Mars is closest to the sun.

While winds don’t reach the speeds depicted in the movie “The Martian,” they can pose a risk to equipment on Mars, Shirley said.

Being able to predict the storms more accurately could make human travel to the planet safer. That won’t mean much for Opportunity, which wasn’t designed to survive dust storms, though the resilient rover did nine years ago.

The 2007 dust storm was one of the first major threats to the twin Mars rovers, Spirit and Opportunity, according to John Callas, project manager for the mission. The rovers, on opposite sides of the planet, only powered up a few minutes each day — just long enough to warm up — during the worst of the storm. NASA went days without communicating with the rovers.

“It’s all about saving energy for the rovers,” Callas said.

The rover’s operators have prepared for the possibility of a dust storm, but at this point, it’s not yet proven whether Shirley’s theory will play out. A storm in September grew into a regional dust storm, but died down before becoming global.

NASA receives regular weather reports from orbiters around Mars and has plans in place to protect its assets on the planet, which include Opportunity and the larger Curiosity rover. Some strategies include parking a rover on a slope to angle the solar panels toward the sun or, in extreme cases, putting it into the power-saving mode used in 2007.

“There is always a likelihood that even if we take all of these extra measures that it may not be enough,” Callas said.

NASA eventually lost communication with Spirit in 2010 after it became stuck in a sand pit. Opportunity is now in its 12th year exploring Mars and started a two-year mission extension this month. Both were expected to last 90 days before dust on their solar panels ended their missions. The winds on Mars that may now pose a threat became an unexpected savior by clearing off the panels on a regular basis.

The rover is setting off on a brand-new mission that will take it a little more than a half mile away. That may not sound very far, but the rover has traveled only about 27 miles in 12 years. There’s always an awful lot of science to do along the way.

“Even after 12 and a half years on the surface, we have perhaps the most exciting science objectives ahead of us,” Callas said. “Which is just amazing considering all that we have done — the best is yet to come.”

Currently, Opportunity is puttering around the rim of the 14-mile-wide Endeavour Crater looking for clues of Mars’ ancient past. Over the next year, the rover will travel through Bitterroot Valley on its way to a gully, stopping to hit scientific points of interest along the way. NASA plans to drive Opportunity down the full length of the gully to the crater floor.

“This would be the first time that any NASA mission, or any Mars mission, has had a chance to investigate a water-carved feature up close,” Callas said. “By examining what it looks like, they can tell what kind of fluid carved it. The evidence is strongly suggestive of water, but we want to examine it up close.”

NASA will create a 3-D model of the gully from Opportunity’s images.

Though Opportunity’s motors and other components have exceeded their life expectancy, the rover is still very functional. NASA discontinued using some of the rover’s memory last year, which means it has to transmit data back to Earth every day, but Callas said the change does not affect the rover’s programming.

The rover has now lasted 50 times longer than its original mission duration, Callas said.