Her life began with a harrowing delivery. Cradled in the protective shell of a landing craft, she arced through the atmosphere at more than 10,000 miles per hour, incandescent, a shooting star over the Arabia Terra desert. At the last moment, the craft severed its parachute and dropped, shrouded in a layer of airbags, hitting the ground like an ungainly rubber ball, bouncing and spinning across the terrain until it finally rolled to a stop. The bags deflated, gently settling the craft into the ocher soil. The shell opened, and out she stretched, limbs unfolding like an origami creation, raising her head, eyes unblinking. She unfurled her solar panels to draw in the thin Martian sun.
She was called “MER-B,” a NASA rover searching for evidence that water, the basis of all known life, once flowed on Mars. She became Opportunity after a student essay contest: The winner was a girl who recalled nights in a Siberian orphanage when the wide sky, pricked with silver, made her feel less lonely.
When Opportunity landed on Jan. 25, 2004, she was given 90 days to live. Surface temperatures on Mars average 80 below, with rocky, arid conditions, constant radiation and violent weather. In her early hours, though, cheers went up in NASA’s Jet Propulsion Laboratory at Opportunity’s unaccountable luck: A photo showed a strip of exposed sedimentary bedrock, which had never been seen on Mars. Her primary mission was geological, to learn the planet’s deep history by reading the rocks, and on her first Martian day, “Sol 1,” she had already begun. In what seemed a blink, she was logging sols in the hundreds, navigating rocky descents with the help of onboard computers, her ambition enlarging like that of a teenager: If I can take this crater, then why not another twice as far or four times larger? The project manager, John Callas, told me that everyone began to wonder, How far can this thing go?
Sol after sol, Opportunity was voracious — drilling, analyzing, snapping pictures for her growing fan club: buff outcrops; a dune named Scylla with two tones, like the fur of an orange tabby cat; feathery clouds drifting west across an afternoon sky. One day she happened upon a metallic meteorite the size of a basketball, just sitting there in the sand, the first discovered on another planet. Around Sol 1,000, in 2006, a passing satellite captured an especially poignant image: In it, Victoria crater spans a half mile, with flows of sand trailing down from scalloped edges like watercolor strokes, the floor carved in a peculiar tortoiseshell pattern. Poised at the precipice stands Opportunity, so tiny before it all. You’re left with an almost parental feeling: wanting to steady her; knowing she doesn’t need the help.
On Sol 2,709, 30 lifetimes behind her, Opportunity arrived at a 14-mile-wide crater called Endeavor, and the full meaning of her explorations became clear: For tens of millions of years, the surface of this world held drinkable water, and something might have lived there. By that point, Opportunity had set the beyond-Earth record for overland exploration, but the signs of aging were unmistakable: Her memory was failing, a front wheel couldn’t steer, a joint in her arm was arthritic, and her older sister, the Spirit rover, had expired in a patch of sand on the other side of the planet.
On May 30, 2018, came warnings of a dust storm that whipped up with unprecedented ferocity, eventually engulfing the planet. Opportunity hunkered down in Perseverance Valley. The sun diminished to a point in the darkening sky, then vanished, starving her of power.
For months and months the scientists at the Jet Propulsion Laboratory tried to make contact, issuing hundreds of commands that might catch her waking under a clear sky or rouse her from cold or confusion. On the evening of Feb. 12, 2019, they gathered in the control room, watching the flatlined telemetry as a few final attempts were made. They played Billie Holiday’s “I’ll Be Seeing You” and knew her mission was over, after more than 5,000 sols. Some fought back tears. What does it mean to mourn for a robot? Opportunity lived each day as if it might be her last, but lived her life as if it would never end.