Ira Flatow on Science: Mars Rover Free to Roam Again

The NASA Opportunity rover, which had been stuck in a sand dune on Mars, is now free to continue roving. Scientists managed to free it from the sand from almost 200 million miles away. Madeleine Brand talks with Ira Flatow, host of NPR's Talk of the Nation Science Friday.


I'm Madeleine Brand, and this is DAY TO DAY.

What do you do if your car is stuck in a rut? Well, usually there's a lot of rocking and rolling. But what do you do if your car is 200 million miles away and on another planet? Well, NASA faced this problem with is Mars rover. And here to explain how they dealt with it is Ira Flatow, host of "Science Friday" and a regular Thursday contributor to DAY TO DAY.

Hi, Ira.

IRA FLATOW reporting:

Hi there.

BRAND: So you have this NASA Opportunity rover stuck in a sand dune spinning all of its wheels?

FLATOW: Yes. And there are six of them. You know, you have a problem with just four wheels on your car spinning helplessly--imagine adding two more that Opportunity has. And then you throw in the fact that you can't pull over a bunch of guys to help you rock the car back and forth, and you really are faced with a big problem: how to get unstuck without digging yourself even deeper.

BRAND: Well, how did the rover get stuck in the first place?

FLATOW: Well, it was sort of a combination of bad luck and, I think, a bit of carelessness. Opportunity has spent the last 16 months rolling around the flat surface of a martian plain. And with this unimagined longevity of the rover, NASA controllers were getting a little bit confident, maybe overconfident in its ability to conquer just about any terrain that it found. And they wanted to cover as much ground as possible. So mission controllers had the rover set to something called blind drive mode. Now you know already from the name that there's going to be trouble here. Blind drive mode means that the Rover was moving very fast, covering almost 700 feet, and not paying a lot of attention to the terrain, since NASA hadn't had very much trouble navigating before. Well, as can be expected, on its way toward visiting its third crater, it got bogged down on a small sand dune--not really much of anything, about a foot high--and it couldn't get out. The wheels just kept on spinning. And you know from driving your own car, you don't want to continue spinning those wheels because you just dig yourself in deeper.

So they took quite a bit of time to figure this out. They took a few weeks, in fact, to figure out just the right way to spin the wheels to get the rover out of this sand trap. And they solved the problem. And it really turned out to be an interesting story because it turned out that this sand was a much different kind than they had encountered before. And having learned this lesson, the blind drive is now off, the kids have given back the car keys, so to speak, and the rover is working again.

BRAND: So that's a relief. They just figured out how to move the wheels in the right way to get it out?

FLATOW: Yeah, they had--you know, they didn't want to sit there wasting time and effort in digging the rover in. They had to figure out the right sequence of wheels and how many turns, and which wheel to turn when to get it out of this trap, which they did.

BRAND: So NASA has been pretty successful with its missions to Mars, and it's planning another one soon. Right?

FLATOW: Yeah. And actually, they've got a couple more lined up in the near future. There's this Phoenix mission that's going to be a stationary robot that will explore the northern plains of Mars, sort of like the area on Earth that would have permafrost on it. And they're looking for that permafrost because they have a shovel here that they want to dig down into the soil and look for ice, water ice, which would mean that possibly, you know, life might have existed there in the past or maybe even in the present.

And then there's another rover that's scheduled to launch in 2009. This will be like a science laboratory on wheels. And they will look specifically for signs of life on Mars. And those things are coming up, and more ahead.

BRAND: Ira Flatow, host of "Science Friday" and a regular Thursday contributor to DAY TO DAY. Thanks a lot, Ira.

FLATOW: You're welcome.

(Soundbite of music)

BRAND: DAY TO DAY returns in a moment. I'm Madeleine Brand.

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