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 has 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 on 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.
Spent the evening at JPL as the last ever commands were sent to the Opportunity rover on #Mars, Tanya Harrison, director of Martian research at Arizona State University, tweeted after a stint at Pasadena's Jet Propulsion Laboratory.
There was silence. There were tears. There were hugs. There were memories and laughs shared. #ThankYouOppy #GoodnightOppy, she wrote.
The nostalgia extended across the generations of scientists who have handled the plucky little adventurer. Godspeed, Opportunity, tweeted Keri Bean, who had the privilege of sending the final message to the robot.
Hail to the Queen of Mars, added Mike Seibert, Opportunity's former flight director and rover driver in another tweet, while Frank Hartman, who piloted Oppy, said he felt greatly honored to have been a small part of it.
Engulfed by a giant planet-encircling dust storm: Is there a more fitting end for a mission as perfect and courageous from start to finish as Opportunity? he said.
The program has had an extraordinary record of success: 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.