IRA FLATOW: This is Science Friday. I’m Ira Flatow. 

[MUSIC – BILLIE HOLIDAY, “I’LL BE SEEING YOU”] 

BILLIE HOLIDAY: (SINGING) I’ll be seeing you. 

THOMAS ZURBUCHEN: I was there yesterday. And 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. 

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. 

BILLIE HOLIDAY: (SINGING) I’ll be looking at the Moon, but I’ll be seeing you. 

IRA FLATOW: That was Thomas Zurbuchen, associate administrator for NASA’s science mission directorate officially declaring Opportunity’s remarkable 15-year long mission to be over. The Mars rover had gone silent since getting caught in a dust storm last summer. On Tuesday night, the space agency made one last attempt to contact the rover, sending it Billie Holiday’s rendition of I’ll Be Seeing You, but Opportunity did not answer. Maggie Koerth-Baker, senior science reporter with FiveThirtyEight is here to talk about sort of a sad occasion. Hi again, Maggie. 

MAGGIE KOERTH-BAKER: Hi. That almost made me cry a little bit in the studio. 

IRA FLATOW: I got a little misty myself. It was almost like a death in the family, was it not? 

MAGGIE KOERTH-BAKER: Yeah, I mean, these rovers are so personable. They kind of feel like they have faces a little bit. People get attached to them. They have Twitter presences. 

Everybody really loves these things. And this one was scrappy and tough. It was only supposed to last for 90 days when it landed in 2004, and instead, it ran for 5,352 days, and it took a planet-wide dust storm to take it down. 

IRA FLATOW: So that’s what happened? It could not recover from the dust storm? 

MAGGIE KOERTH-BAKER: Yeah. It had gotten stuck in a previous dust storm a few years ago that it did recover from, but this one went on a lot longer. And the rover was powered by solar power, so its solar panels got covered up with dust. And after a certain point, it didn’t have enough energy to kind of keep itself alive long enough for the dust to clear. 

IRA FLATOW: Because they had sent it, what, more than 800 commands? 

MAGGIE KOERTH-BAKER: Yeah, yeah. Over the course of the past few months, and it just– it didn’t ever contact us back. 

IRA FLATOW: Let’s talk about some of the highlights of Opportunity’s time on Mars. We checked in with Opportunity Mars rover deputy project scientist Abigail Fraeman this week and asked her to share her favorite memory of the mission. 

ABIGAIL FRAEMAN: It’s really hard for me to pick a favorite memory from this mission because I have so many over the past 15 years. One of them that really sticks out in my mind though was in 2010 when we first pulled up to the rim of Endeavor Crater. Endeavor Crater is this big 22 kilometer diameter impact crater, and we’d been seeing it in the distance for months before we got there. 

Pulling up to this crater was basically the start of a new mission. In the rim of the crater, we encountered new kinds of rocks, much older rocks than we’d seen before. And it was so cool to think that after so many years, the exploration was just as fresh and exciting as it was the day we landed. 

IRA FLATOW: Maggie, do you have some of your favorite highlights? 

MAGGIE KOERTH-BAKER: I think one thing that I thought was really exciting to me was the fact that this rover actually held the record for longest distance driven by a wheeled vehicle off of planet Earth. It went 28 miles in its time on Mars. Which doesn’t really seem like a lot, but when you think about everything that sort of had to happen for this little guy to be there and to have the power to drive those miles, that’s a lot of effort and a lot of work. And it’s 28 miles that is very important to our understanding of Martian history, and also of what the water systems on Mars had once been a long time ago. 

This rover picked up a lot of evidence for ancient water on Mars. It found signs of hematite, which is a mineral that forms in water. At that Endeavor Crater that was mentioned, it was finding these white veins of gypsum that suggests that water was kind of coming up to the ground through tiny fractures at one point. 

And it found clay minerals that would have been formed in a kind of water that had a neutral pH. So that’s kind of talking about something not too acidic, not too basic, water that’s akin to what you’d find in the drinkable lake here on Earth. This was a really important little rover. And it found us a lot of interesting information about what Mars used to be like. 

IRA FLATOW: It stretched out its three month tour to 5,000 days. 

MAGGIE KOERTH-BAKER: Yeah. 

IRA FLATOW: And we currently have other explorers still there, right? 

MAGGIE KOERTH-BAKER: Right. Right. We have we have Curiosity is up there. A little bit more jerry-rigged and aging than she used to be, but she’s there. 

There’s a non-mobile lander also. And there are two new rovers that are set to be launched in 2020. And both of those have been designed using knowledge and skills that we’ve sort of picked up from building these rovers like Opportunity and Curiosity and Spirit that have lasted far longer than they were expected to, so probably, these new 2020 rovers will as well. 

IRA FLATOW: Let’s move on to some other interesting– the week is so filled with interesting news. There’s some good news and some bad news out of Greenland, right? What’s the bad news first. 

MAGGIE KOERTH-BAKER: Well, I mean, the bad news is that Greenland is melting a lot. There’s been several studies over the past year that kind of came out showing big amounts of melt in that ice sheet. I think there was one from December that was showing melting five times faster over the last 20 years than it had been in pre-industrial times. They were using ice cores to kind of look all the way back 350 years ago. 

But one of the things that was coming out this week is the Greenland government sort of starting to talk about how to make the most of a bad situation. So as these glaciers, as this ice sheet is starting to melt, what’s coming out of it is sand and gravel, and that’s kind of flowing down towards the sea. And one of the things that they’re starting to realize is that those are things that they can collect and that they can sell. And ironically, what they would be selling it for is so that other places with rising sea levels from glacier melt can build up the land. It’s a very– very fun little shell game that we have going on here. 

IRA FLATOW: Just move the sand from one place to another. 

MAGGIE KOERTH-BAKER: Right. Because of climate change in both cases. 

IRA FLATOW: Maybe you could get your own bottle of glacier sand. 

MAGGIE KOERTH-BAKER: Yes. 

IRA FLATOW: So all these entrepreneurial opportunities. Thank you, Maggie. 

MAGGIE KOERTH-BAKER: Yeah. 

IRA FLATOW: Maggie Koerth-Baker, senior science writer with FiveThirtyEight.

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