RACHEL MARTIN, HOST:
Ten years ago, NASA's rover, optimistically named Opportunity, landed on Mars on what was to be a three-month mission. But Opportunity is still going strong today, still searching the Red Planet, sending data and images back to NASA. To celebrate Opportunity's decade of life, we called Jim Bell. He's an astronomer at Arizona State University. Welcome to the program.
JIM BELL: Great to be here.
MARTIN: So, take us back, Jim. What was Opportunity originally designed to do?
BELL: You know, Opportunity is the twin with Spirit. Both rovers landed on Mars in January of 2004, and both of them were designed to look for evidence of habitable environments in the past.
MARTIN: Spirit is no longer. What happened to that rover?
BELL: You know, they're solar-powered rovers. And Mars has these famous dust storms and a very dusty atmosphere. And over time that dust is settling on the solar panels. And we'd get lucky sometimes. The wind would come along and blow it off. But over time, Spirit's panels got dustier and dustier and dustier. And in 2010, the rover got stuck in some sand and it just wasn't enough power to extract ourselves. And that was the end of the mission.
MARTIN: What are the most significant scientific discoveries or revelations that are credited to Opportunity?
BELL: Right when we landed, we saw these beautiful rocky outcrops in a small crater that we landed in. And we drove Opportunity over to them and we saw evidence of water-formed minerals, you know, spectacular evidence that indeed there was liquid water on the surface of Mars near the surface of Mars long ago or early in the history of the planet, an environment that, you know, if we could have been there looking at it three and a half billion years ago, would have seem very, very Earth-like. And so the presence of liquid water, heat sources like the volcanoes and impact craters that we know were there and the possibility of organic molecules from asteroids and comets, which are impacting the planets all the time. Those are the ingredients you need for habitability.
MARTIN: The rover Opportunity most recently found this rock described by some as looking like a jelly doughnut. Can you talk a little bit about that? What makes discoveries like this that seem inconsequential so fascinating?
BELL: You know, there was a little rock that might have been pinched by the wheels, dislodged - the wheels were spinning and kind of kicked it up and scooted it into an area where a previous picture didn't show any rocks. But what seems to have happened is it was flipped over also. And who knows the last time the bottom of this rock saw the sunlight? Could have been three billion years ago, for all we know. And so the kinds of minerals and the kind of surface atmosphere chemistry that happens on the tops of rocks seems to be different than what happens on the bottom. So, we're trying to figure it out but it's just a fun surprise. And these things happen even 10 years after landing.
MARTIN: Jim Bell, an astronomer at Arizona State University talking about the rover Opportunity. Jim, thanks so much for talking with us.
BELL: Mars rocks. Thanks.
MARTIN: This is NPR News.