#ThanksOppy: Twitter Mourns the Demise of NASA's Opportunity Rover

During 14 years of intrepid exploration across Mars, it advanced human knowledge by confirming that water once flowed on the red planet -- but NASA's Opportunity rover has analyzed its last soil sample.

The robot had been missing since the US space agency lost contact during a dust storm in June last year and was declared officially dead on Wednesday, ending one of the most fruitful missions in the history of space exploration.

Unable to recharge its batteries, Opportunity left hundreds of messages from Earth unanswered over the months, and NASA said it made its last attempt at contact Tuesday evening.

"I declare the Opportunity mission as complete," Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate told a news conference at mission headquarters in Pasadena, California.

The community of researchers and engineers involved in the program were in mourning over the passing of the rover, known affectionately as Oppy.

"It is a hard day," said John Callas, manager of the Mars Exploration Rover project.

"Even though it is a machine and we're saying goodbye, it's very hard and it's very poignant."

"Opportunity may be a robot, but it was a robot *built by people,*" Tanya Harrison, director of Martian research at Arizona State University tweeted.

"It’s very emotional knowing that I really was there for her until the very end," tweeted Keri Bean, who had the "privilege" of sending the final message to the robot.

Former NASA astronaut Terry Virts too gave a farewell.

The only rover active on Mars, Curiosity, penned down an emotional goodbye.

NASA shared Oppy's journey in a tweet.

Social media users teared up upon learning the sad news. Some shared the final heartbreaking "message" from the rover: “My battery is low and it’s getting dark.”

The program has had an extraordinary record of success: 28.1 miles (45.2 kilometers) traversed, more than the Soviet Union's Lunokhod 2 moon rover during the 1970s and more than the rover that US astronauts took to the moon on the Apollo 17 mission in 1972.

"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," NASA Administrator Jim Bridenstine said in a statement.

Opportunity sent back 217,594 images from Mars, all of which were made available on the internet.

Opportunity landed on an immense plain and spent half its life there, traversing flat expanses and once getting stuck in a sand dune for several weeks. It was there, using geological instruments, that it confirmed that liquid water was once present on Mars.

During the second part of its life on Mars, Opportunity climbed to the edge of the crater Endeavour, taking spectacular panoramic images -- and discovering veins of gypsum, additional proof that water once flowed among the Martian rocks.

"This isn’t the end. Opportunity lives on in current and future Mars missions," the official handle of Mars Rovers wrote in a tweet.

(With AFP inputs)