A vast dust storm blanketing about a quarter of the surface of Mars has threatened NASA’s Opportunity rover, plunging the solar-powered vehicle into what the space agency has described as a “dark, perpetual night.”
With its primary energy source obscured, the rover, which sits in the Perseverance Valley of Mars near the center of the storm, appears to have automatically entered a power-saving mode in which it will remain until the sun re-emerges, agency officials said.
“We’re concerned, but we’re hopeful that the storm will clear and the rover will begin to communicate with us,” John Callas, the Opportunity project manager, told reporters on a Wednesday conference call with other NASA officials.
Opportunity is at historically low energy levels. The rover weathered another serious storm in 2007, but the current storm is much worse, having intensified more rapidly and more completely blocking out the sun, NASA said.
“It is unprecedented in the pace at which it has grown and spread across the globe,” said Jim Watzin, the director of NASA’s Mars exploration program.
The storm, first spotted on May 30, is now among the most intense ever observed on Mars. It covers an area nearly the size of North America and South America combined and could encircle the planet within a matter of days, as the storm in 2007 and another in 2001 did, officials said.
In its low-power mode, the rover has shut down many of its functions. A mission clock remains running to periodically wake an onboard computer to check power levels before going to sleep again.
But even in that mode, the rover must balance battery conservation against subfreezing temperatures. The heaters it uses to survive Mars’s extreme cold draw power from the battery, but NASA officials were optimistic about Opportunity’s prospects because the planet entered spring last month and dust storms can keep temperatures high.
“As long as the rover stays warm enough, and our predictions are that it will, we can go any number of days,” Mr. Callas said. “We are approaching summer, so we haven’t even hit the warmest part of the year for the rover at this site.”
Because of the amount of dust swirling over the valley where Opportunity lies, it isn’t clear how long the rover will have to wait to receive enough sunlight to recharge. Debris could also settle on its panels, obscuring the light, but winds have helped avert that fate in the past, officials said.
Opportunity was one of a pair of rovers that landed on Mars in 2004 and proceeded to make important discoveries about the water in the planet’s past.
Opportunity, for example, found evidence that at least one part of Mars had stayed wet long enough to sustain microbial life. The other rover, Spirit, found that the planet was once far wetter than it is today.
Both long outlived their 90-day missions, with NASA abandoning Spirit in 2011, two years after it got stuck in a sand trap.
While members of the NASA team working on Opportunity are optimistic about its chances, they’ve grown attached and can’t help worrying, Mr. Callas said.
“It’s like you have a loved one in a coma at the hospital,” he said. “The doctors are telling you that you just have to give it time and she’ll wake up. All the vital signs are good, so it’s just waiting it out. But if it’s your 97-year-old grandmother, you’re going to be very concerned.”