In January 2004, the NASA rovers Spirit and Opportunity bounced onto Mars's surface with a 90-day mission to do as much science as they could before harsh conditions on the red planet's surface stopped them in their tracks. The rovers persevered beyond all expectations: Spirit survived for more than seven years, and Opportunity is still kicking after nearly 15 years, a robotic Methuselah that has provided researchers with vital clues about habitability on ancient Mars.
But now, Opportunity is facing a severe setback. The rover is currently hunkered down in Mars's Perseverance Valley, trying to wait out one of the most intense dust storms ever observed on the red planet.
“We should be able to ride the storm out,” John Callas, the project manager for NASA's Mars Exploration Rovers, said at a NASA press conference on Wednesday. “We're concerned, but we're hopeful that the storm will clear and the rover will communicate to us.”
Since the Mars Reconnaissance Orbiter spotted the storm on May 30, the tempest has kicked up enough dust to cover a quarter of Mars's surface. A U.S-size portion of this area is now choked with so much dust, martian days resemble twilights—or worse. (See pictures of 'Mars' here on Earth.)
“This is quite an unusual storm,” says Bruce Cantor, a scientist with Malin Space Science Systems who's considered an authority on Mars weather. “This [storm] occurred a full month earlier than the previous earliest reported storm along this storm track, and nearly two months earlier than we've seen in the last few Mars years.”
Cantor adds that the storm will grow more severe in the next few days and probably will spawn Mars's first global dust cloud since 2007. At their most intense, these clouds can block more than 99 percent of incoming sunlight.
This series of images shows simulated views of a dust-darked martian sky blotting out the sun from the Opportunity rover's point of view.
PHOTOGRAPH BY NASA, JPL-CALTECH, TAMU
The maelstrom is bad news for Opportunity: Unlike its nuclear-powered successor Curiosity, Opportunity is largely solar-powered. As of Sunday, Opportunity was pulling in a meager 22 watt-hours from its solar panels, less than four percent of the energy it normally generates.
NASA suspended Opportunity's science operations on June 8 as the storm worsened, and the rover last made contact with mission control on the morning of June 12. Researchers expect that the rover has autonomously entered a low-power hibernation, where only the mission clock continually operates.
Chances of Survival
This is the first storm that's knocked out communication between Earth and Opportunity, but rumors of the rover's death may be premature. While day-night temperature swings may wear on the rover's electronics, it's unlikely that the rover will succumb to Mars's famously low temperatures. Dust clouds actually help keep surface temperatures warmer, and Mars is entering its summer.
In the press conference, Callas added that forecasted temperatures don't dip below -33 degrees Fahrenheit, warmer than Opportunity's minimal operating temperature of -67 degrees. He also emphasized that there are contingencies in place even if power levels dip so low that the mission clock temporarily shuts off.
This also isn't the first dust storm that Opportunity has faced: It last stared one down in 2007. Mike Seibert, Opportunity's former senior driver, says that the prior storm contaminated one of the rover's scientific instruments but otherwise left the spacecraft intact. He hopes for no more than a similarly non-fatal bruising here.
“As long as the rover stays somewhat electrically alive through the storm, it's not going to be easy, but I'm optimistic that the team will recover the rover and pick up right where they left off,” he says.
Cantor and Seibert caution that reestablishing contact with Opportunity might take weeks to months, depending on how long the global dust cloud persists. In the meantime, the rover's support team and admirers will continue to wish “Oppy” well, even as they hold their breath.
“Somehow, everybody can imagine themselves in the rover, so when the going gets tough, there's been a big outpouring of support,” says Seibert. “After 14 and a half years on the surface, it's become part of everyone's lives.”