NASA declared Wednesday that its Opportunity rover on Mars has finally expired, nearly 15 years after it landed on the Red Planet. It had been expected to last only about 90 days.

Opportunity’s remarkable durability and record of scientific discovery was, the space agency said, among “the most successful and enduring feats of interplanetary exploration.”

The small rover stopped communicating with Earth when a severe dust storm blanketed the entire planet last June. Engineers spent months trying to revive it, sending more than a thousand commands in hopes of restoring contact.

Designedd to travel only about a thousand yards from its landing point, Opportunity wound up traveling more than 28 miles before succumbing to the dust in the appropriately named Perseverance Valley.

“It is because of trailblazing missions such as Opportunity that there will come a day when our brave astronauts walk on the surface of Mars,” said NASA Administrator Jim Bridenstine. “And when that day arrives, some portion of that first footprint will be owned by the men and women of Opportunity, and a little rover that defied the odds and did so much in the name of exploration.”

Its twin rover, Spirit, landed on the other side of Mars a few weeks earlier than did Opportunity, and managed to travel nearly five miles by the time it failed in 2011.