NASA’s Opportunity rover began its 15th year on Mars this week, although the intrepid robotic explorer may already be dead.

“I haven’t given up yet,” said Steven W. Squyres, the principal investigator for the mission. But he added, “This could be the end. Under the assumption that this is the end, it feels good. I mean that.”

The rover — which outlasted all expectations since its landing on Mars in 2004 and helped find convincing geological signs that water once flowed there — fell silent last June when it was enveloped by a global Martian dust storm. In darkness, the solar panels could not generate enough power to keep Opportunity awake.

To be taken out by one of the most ferocious storms on Mars in decades: “That’s an honorable death,” Dr. Squyres said.