RIP Opportunity: A eulogy for the beloved Mars rover

The little rover that could.

martian-dust-devil

Dust Devil

NASA's Mars Exploration Rover Opportunity recorded this image of a Martian dust devil twisting through the valley below. The view looks back at the rover's tracks leading up the north-facing slope of "Knudsen Ridge," which forms part of the southern edge of "Marathon Valley."NASA/JPL-Caltech

Today we mourn the loss of a friend so stalwart we nearly forgot we wouldn't have them forever. After 15 years investigating the surface of Mars, NASA's Opportunity rover has joined its late twin Spirit in the big scrapyard in the sky.

You shouldn't blame yourself for taking Opportunity for granted; the robot landed in 2004 with the task of searching the red planet for signs of ancient water for just over three months. Opportunity surpassed its primary mission by more than 60 times, and outlived its twin rover by eight years. Built for a sprint, Opportunity ran a marathon—and then some. (And yes, we know, it's probably been "dead" since June—but 15 is such a nice round number an Opportunity deserves it, okay?)

NASA makes all its robots to last—the recently departed Cassini orbiter had a primary mission of three years and persisted for 13—but Opportunity outdid them all. Oppy drove farther than any rover in history and trekked for longer than any other surface mission. It outlived low-rise jeans and jelly bracelets. It outlived LOST. It outlived Brad and Jen and Brangelina. It may not have had the social media savvy of its cousin Curiosity, but Opportunity has done its duty with quiet dignity for far longer than we could have hoped.

Opportunity sent home stunning images of the hostile world that eventually did it in—one that we hope to soon visit in person, and perhaps even live on. In studying more than 100 unique impact craters, it found multiple signs of water-long-past on the Martian surface. The robot's longevity also gave it a chance to monitor how dust and clouds vary over time on this alien world, providing insight into how solar panels and other infrastructure might fare in future missions.

It was that same atmospheric variability that killed Opportunity. The trouble started on June 1, 2018, when the Mars Reconnaissance Orbiter beamed home photos of a burgeoning dust storm. Such tempests can last for weeks at a time, and this one cast Opportunity into darkness. Its solar panels near-useless, NASA scientists worried that Opportunity might not emerge into the light before Martian winter made temperatures plummet. Without the battery reserves necessary to keep its systems warm, they knew, its circuitry would suffer catastrophic damage—the same fate met by its twin, Spirit, in 2010.

Still, NASA held out hope. Oppy went to sleep to conserve its energy and engineers willed it to survive the worst of the storm. But a few weeks later, it missed a scheduled call home. The storm raged on until August. The Opportunity team revived an old tradition of sending wake-up calls to the robot each morning featuring cheerful songs, but their calls went unanswered.

On Tuesday, scientists at NASA's Jet Propulsion Lab serenaded their sweet prince one last time. Billie Holiday's "I'll Be Seeing You" set the mood for a tearful night of goodbyes as the team waited for a call they knew was unlikely to come. NASA is expected to confirm the loss of the robot at a press conference Wednesday at 2 p.m. Eastern.

Curiosity is still hard at work, and other rovers will soon join it. But Opportunity will always hold a special place in our hearts. It was an impossibly intrepid explorer that not only expanded our knowledge of Mars, its history, and its habitability but informed the designs and missions of countless space rovers yet to come. Sleep well, Opportunity. We’ll be seeing you.