MICHEL MARTIN, HOST:
This week, we got some sad news from NASA. The Mars rover known as Opportunity was officially announced dead. The original mission was to learn more about Mars. It launched alongside its twin, Spirit, in 2003 before we knew much about the Red Planet. Opportunity was expected to last on Mars for 90 days. But the little rover that could, as it's called, ended up staying there for 14 years, covering a marathon's worth of Martian territory.
DAVE LAVERY: This project has been a central part of my professional life for the last 20 years.
MARTIN: That's Dave Lavery, who's been on Opportunity's team since the very beginning.
LAVERY: These two robots - they became family members to us over the years. And Opportunity very quickly became known as Oppy. And both the rovers are female. They're not it. They're she.
MARTIN: Oppy provided a window into Mars, making discoveries along the way. One of the biggest - at one point, Mars had liquid flowing water, suggesting it could have sustained life. She also posed new challenges to the NASA team, including keeping track of Martian time.
LAVERY: We actually had special watches created that kept Mars time, and several of us who were working on both Spirit and Opportunity ended up wearing four different watches - one for Pacific Coast Time, one maybe for East Coast time, if our office was back home, one for Spirit time and one for Opportunity time.
MARTIN: The rover itself had some quirks. At some point during its 14-plus years on Mars, one of its wheel motors started wearing out, and the team, including associate administrator Thomas Zurbuchen, started to worry the wheel may get stuck.
THOMAS ZURBUCHEN: So what the rover actually had to do is go backwards. So most of this journey, that marathon, it did in reverse.
MARTIN: In the end, the rover experienced a Martian storm so dark and cold the team at NASA thinks the internal batteries were altered beyond repair. Dave Lavery says Oppy's last communication with the team was grim.
LAVERY: I'm getting cold. It's getting dark. My battery levels are getting low. And sort of here's how fast things are dropping.
MARTIN: But Zurbuchen says the rover's legacy will live on, especially in helping plan future trips to Mars.
ZURBUCHEN: Mars 2020 is the first leg of a round trip, the first round trip to Mars ever - a historic moment.
MARTIN: On the final day of attempted communication with Opportunity, the team did what they had done every morning for 14 years. They sent the rover a wakeup song, like ground control does for human flight crews during a mission. But this time, they knew the rover wouldn't wake up. The song they chose - Billie Holiday's "I'll Be Seeing You." Thanks, Oppy - mission accomplished.
(SOUNDBITE OF SONG, "I'LL BE SEEING YOU")
BILLIE HOLIDAY: (Singing) I'll be seeing you in all the old familiar place that this heart of mine embraces... Transcript provided by NPR, Copyright NPR.