Opportunity on Mars, 2004-2019: NASA sings requiem to a rover

Ths colorized image of the Opportunity rover’s shadow was taken on July 26, 2004, by the rover’s front hazard-avoidance camera as it moved farther into Endurance Crater in the Meridiani Planum region of Mars. (NASA / JPL-Caltech Photo)

After months of silence from Mars, NASA finally read the rites over its Opportunity rover, hailing the six-wheeled machine as an overachiever that found some of the first and best evidence of the Red Planet’s warmer, wetter past.

The solar-powered rover’s demise was no surprise: It fell out of contact with controllers at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., last June — due to a globe-girdling Martian dust storm that kept Opportunity from charging its batteries.

Mission managers tried all sorts of tricks to wake up the comatose rover and re-establish communications, but it was to no avail. The last attempt was made on Tuesday night.

Today’s final Opportunity news briefing took on the trappings of a memorial service, featuring far more ceremony than NASA employed when the Spirit rover — Opportunity’s twin in the Mars Exploration Rover mission — went dead in 2011.

“I was there with the team as these commands went out into the deep sky, and I learned this morning that we had not heard back, and our beloved Opportunity remained silent,” said Thomas Zurbuchen, NASA’s associate administrator for science. “It is therefore that I’m standing here, with a sense of deep appreciation and gratitude, that I declare the Opportunity mission as complete, and with it, the Mars Exploration Rover mission as complete.”

Both rovers bounced to the Martian surface, wrapped in protective airbags, in January 2004. On opposite sides of the planet, each rover came upon evidence that water once flowed on the Red Planet. Near its landing site in the Meridiani Planum region, Opportunity found “Martian blueberries” containing hematite, a mineral that forms in the presence of water.

Cornell astronomer Steve Squyres, who was the principal investigator of the Mars Exploration Rover mission, recalled that the initial evidence suggested Mars’ ancient water was highly acidic. “We were running around saying, ‘Water on Mars! Water on Mars!’ It was really sulfuric acid on Mars, right?” he said, half-jokingly.

Later evidence gathered at Endeavour Crater indicated that the water at that location in ancient times might have been drinkable.

Opportunity and Spirit were designed to last at least 90 days on Mars, but scientists marveled that both rovers lasted years longer than expected. Project manager John Callas said there were two main reasons why the rovers were such overachievers.

He explained that scientists expected the rovers to grind to a halt when enough of Mars’ red dust settled on their solar panels to choke off their power generation systems. They were surprised to find out that Martian winds periodically swept the panels clean.

“This, on a seasonal cycle, actually became pretty reliable,” Callas said.

The second factor had to do with the rovers’ batteries. Opportunity’s batteries went through more than 5,000 charging cycles, and were still capable of holding an 85 percent charge after more than 14 years of use. “We would all love it if our cellphone batteries lasted this long,” Callas said.

Opportunity’s odometer logged 28.06 miles of travel, which set the record for the longest trek on a world beyond Earth.

Over 15 years, 28+ Miles traveled, 228,771 images taken and SO much science done. Rest easy now Oppy. #GoodnightOppy #ThankYouOppy @NASA @MarsRovers pic.twitter.com/zre0CPA0cA

— Geoff Barrett