LOS ANGELES -- NASA's Opportunity rover is incommunicado after being hit by a severe, continent-scale dust storm on Mars, space agency officials said Wednesday -- and they're not sure exactly when they'll hear from it again.
Officials say the rover has probably fallen asleep after being unable to generate enough energy from its solar panels due to the dust-darkened skies.
"The project team is very concerned," said John Callas, the mission's project manager based at the nearby Jet Propulsion Laboratory. "We're watching the weather and we're listening to the Deep Space Network for signals."
Mission officials first got word that a storm could be headed toward the rover at the start of June. Within a few days, the rover's view was growing dimmer and its solar panels were generating less and less energy.
By June 6, the rover was put into a temporary power-saving mode, one that would save energy but provide just enough activity to keep the rover warm. A similar routine was used two days later.
By Sunday, Curiosity's view of Mars was completely dark.
The good news is that Mars is headed into its summer season, which means that temperatures should not dip low enough to threaten the rover's systems, mission officials said. Once the storm clears and enough sunlight hits its solar panels, it should be able to wake up and make contact again.
Still, Callas said the team was concerned about the aging rover as it faced this enormous storm, which could grow to fully envelop the planet in two to three more days. Having spent more than 14 years on the red planet, Opportunity has far outlived its planned 90-day mission.
"This team has a very strong bond with the rover," Callas said, comparing the machine to an elderly family member in the hospital.
"The doctors are telling you that, 'OK, you've just got to give it time and she'll wake up, all the vital signs are good,' so it's just waiting it out," he said. "But if it's your 97-year-old grandmother, you're going to be very concerned."