A huge dust storm that’s now 14-million square miles wide, covering a full quarter of the red planet, has blotted out the sun above Perseverance Valley, Opportunity’s home. The storm could actually become a global tempest in the days to come, according to NASA.

And while there’s a chance the hardest-working rover on Mars won’t make it through the storm, scientists are still hopeful.

“We’re concerned, but we’re hopeful that the storm will clear and that the rover will begin to communicate to us,” John Callas, Opportunity project manager, said on a press call Wednesday.

“We think we can ride this out for a while.”

If you were standing next to the 5-foot-tall rover and looked up into the sky, you wouldn’t be able to see the sun. Dust would be whipping around as Opportunity sits on the rusty ground, with all but its mission clock turned off, waiting for the storm to end.

Opportunity — which has been exploring the Martian surface for about 15 years — charges itself through solar panels that feed its batteries. Because of the storm, those panels aren’t receiving enough sunlight to fully charge up the rover, meaning that it’s now trying to save what little power it does have before getting in touch with Earth again.

“Due to an extreme amount of dust over Perseverance Valley, mission engineers believe it is unlikely the rover has enough sunlight to charge back up for at least the next several days,” NASA said in a mission update posted last Tuesday night.

“NASA engineers attempted to contact the Opportunity rover today but did not hear back from the nearly 15-year-old rover. The team is now operating under the assumption that the charge in Opportunity’s batteries has dipped below 24 volts and the rover has entered low power fault mode, a condition where all subsystems, except a mission clock, are turned off.”

The mission clock will trigger the computer to turn back on to check power levels sporadically, NASA said.

If the computer finds that power levels are good, it will command the rover to get in touch with engineers back on Earth, but if not, it’ll put the rover back to sleep again to wait out the storm.

According to Callas, NASA believes that the rover should be able to ride out the storm well, even if it lasts for several more days. The dust storm is actually keeping it relatively warm on Mars, so Opportunity will likely stay warm enough to turn back on when the dust clears.

That said, things may get worse before they get better.

If the rover’s power dips even lower than it is now, it’s possible that Opportunity’s clock could turn off, meaning that NASA will need to remain vigilant to listen for any pings from the rover that would come at somewhat random intervals if it’s able to come back online, Callas said.

People working with the rover have also become attached to it over the years, so even if things are looking okay, it’s still a scary prospect that this rover is alone and unable to phone home on Mars.

“It’s like you have a loved one in a coma in the hospital. You have the doctors telling you that, ‘Okay, 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,” Callas said.

“But if it’s your 97-year-old grandmother, you’re going to be very concerned, and so we are. By no means are we out of the wood here.”

NASA’s Curiosity rover — the agency’s other functioning rover on Mars — is also seeing some haze in the atmosphere due to the dust storm, but it isn’t experiencing any ill effects from the storm, NASA said.

Opportunity has lived an amazing life on Mars.

The rover touched down on the red planet with its twin Spirit in January 2004, and the robotic emissaries got to work right away in different parts of the world.

Opportunity and Spirit have totally overhauled our understanding of Martian geology, revealing never-before-seen rocky features on Mars. The rovers found evidence of past volcanic activity, water flows, and meteor impacts.

Both rovers were only designed to function on Mars for about 90 days, but both outlived that estimate by leaps and bounds.

Spirit operational life on Mars ended in 2010, but hopefully its twin will make it through the storm and keep on trucking for years to come.

UPDATE: June 13, 2018, 2:05 p.m. EDT This story was updated to include more details on the storm and Opportunity from NASA.