The longest lasting Mars reconnaissance mission in history officially came to a close on February 13, as announced in a NASA press conference last Wednesday.

The Opportunity Rover (also known as MER-1 and nicknamed “Oppy”) was a rover launched to Mars on July 7, 2003, and landing on the Martian surface on January 25, 2004. Originally only meant to last for 90 days, the $400 million mission lasted for 15 years—55 times its intended lifespan. With this extended lifetime, Opportunity gave the scientific community more information on the Red Planet than previously imaginable.

Opportunity assisted in many missions and on numerous scientific fronts, such as the examination of soil and rock samples, search for hematite and clay deposits—which is intertwined with the discovery of water, and sulphuric acid on the Martian surface. After these incredible strides of discovery, Opportunity lost communications with NASA H.Q. on June 10, 2018 due to a planet-wide dust storm, causing over 1,000 attempts to reestablish communications. Despite all of this, Opportunity did not respond. As a final goodbye, NASA sent one last wake-up song and goodbye, Billie Holiday’s “I’ll Be Seeing You”.

Opportunity’s last data transmission to NASA, poetically translated on Twitter by Jacob Margolis, a science reporter for KPCC-FM radio, essentially read, “My batteries are low, and it’s getting dark,”—a phrase that has become entwined with the death of Opportunity.

Project manager John Callas stated in a reunion with the team responsible for the Opportunity missions, “This is a hard day. Even though it’s a machine and we’re saying goodbye, it’s still very hard and very poignant, but we had to do that. We came to that point.”

Over the days following, thousands of scientists, writers, actors, students, and internet denizens mourned the death of the rover, taking to Twitter to express their grief. The official Mars Rover Twitter account wrote, “To the robot who turned 90 days into 15 years of exploration: you were, and are, the Opportunity of a lifetime. Rest well, rover. Your mission is complete.”

Another user gave a farewell message written in binary, translating to “Godspeed, Oppy”. Dr Tanya Harrison, director of research at Arizona State University NewSpace, stated in a video, “There was silence. There were tears. There were hugs. There were memories and laughs shared.”

Twitter user The Mediocre Sulk described the situation best when he said, “The human ability to empathize and pack-bond is a beautiful, weird, messed up thing. It’s 2:40am and I’m on the verge of crying over the #Opportunity rover that I barely even knew anything about until now.”

Despite the sadness that people might feel for this gentle robot, it was a mission that gave us a grand stride in discovery. It was a long-lived journey, and an expedition well done.

Despite the death of Opportunity, Curiosity will continue in its predecessor’s tracks, bringing more information in its expedition.

The longest lasting Mars reconnaissance mission in history comes to a close.