JOHN YDSTIE, host: Santa Anita, Gusev Dunes - they're not summer vacation destinations, unless you're planning an interplanetary road trip. These are some of places NASA's Mars Rover Spirit visited during its six years exploring the red planet. Spirit died in May after a year stuck in the Martian sand. Her rover twin, Opportunity, though, perseveres, trundling across the Martian surface looking for evidence of water. Last week, NASA announced the latest destination for Opportunity has been named Spirit Point. John Grant is a planetary scientist at the National Air and Space Museum. He's worked on Mars Rovers since well before they landed in 2004. He joins us in our studio. Dr. Grant, welcome to the program. Thanks for coming in.
Dr. JOHN GRANT: Thanks for having me.
YDSTIE: So, let's first talk a little bit about Spirit. How would you characterize Spirit's mission: better than you expected, worse than you expected, about what you expected?
GRANT: Better than I expected would be a vast understatement for rovers that were supposed to last 90 days and go something like 600 meters; to go miles and miles literally and to last six years is just astounding.
YDSTIE: Spirit took some stunning photos. It's kind of a harsh beauty, like the American Southwest. What does Spirit Point, the place where Opportunity is headed?
GRANT: Spirit Point is very interesting because it's around the rim of this huge crater - huge relative to anything that opportunity has seen. It's called Endeavor and it's something like 14 miles across. And we've descended down over the lip of the terrain to Spirit Point with this incredible, vast view in front of us, almost like a view from the side of Death Valley. So, it's really very familiar in some ways but alien, as you said, in others.
YDSTIE: And what do you know about that topography and how it was created?
GRANT: Well, we know that the topography is related to an ancient impact. A meteorite slammed into the planet very early in Mars' history. And what makes it so interesting is that it's old material that's poking up through the younger plains that we've been traversing on. And this old material contains clays - things that suggest a wetter climate in the past and one that was more Ph neutral.
YDSTIE: So, where was Opportunity coming from and how long did it take to get it to Spirit Point?
GRANT: Opportunity has been on a long trek across the Meridiani Planum plains. It's about 12 kilometers of crow flies, but because we had to go around a bunch of ripples that are sort of like little sand dunes, we kind of took a scenic route of 19 kilometers. And the science team is just elated because we've reached this terrain that is obviously different than anything that we've been on before.
YDSTIE: You've been a part of the Mars Rover project for decades. Do you feel a little bit like a proud parent?
GRANT: I feel like I'm getting old. It's been something like eight years since I joined the science team, and, of course, the mission's been going on for seven plus. And every day that we do the planning, there's a routine about it but it never gets to be a routine. It's always different. And the people that we've met, the people that we've worked with, we do it all remotely now. But you have a sense that they're there in the room. We just know each other so well.
YDSTIE: What are you most proud of?
GRANT: I think that as an individual, I'm most proud of the team's accomplishments with understanding not only what happened at Meridiani Planum - that there has been water there, that this was a place that while arid sometimes was wet. But also at Spirit's landing site in Gusev Crater, the understand that we gained from the Colombia Hills, that this was a place in early Mars' history where there was water and volcanic activity that in some ways I almost felt like if I could stand there and squint a little bit, you know, maybe it was kind of like Yellowstone or something like that with fumaroles and steam and other activity and perhaps even habitable places for things to get going and live.
YDSTIE: John Grant is a geologist who works on NASA's Mars Rover project. Thanks for coming in.
GRANT: Thank you. Transcript provided by NPR, Copyright NPR.