How This Mission To Mars Is Different From Others

Aug 5, 2012
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This is WEEKEND EDITION from NPR News, I'm Linda Wertheimer

Mars is about to receive a visitor. If everything goes according to plan, a one ton, 6-wheeled, nuclear-powered rover will touch down in Gale Crater early Monday morning, or late Sunday night if you are on the West Coast. NASA's Mars Science Laboratory, nicknamed Curiosity, is carrying a suite of instruments designed to search for signs that the Red Planet once had an environment where life might have evolved.

Mission control for Curiosity is at NASA's Jet Propulsion Laboratory in Pasadena. And that is where NPR science correspondent Joe Palca will be tonight. He joins us now from NPR West, which is about 25 miles by freeway from JPL. Good morning, Joe.

JOE PALCA, BYLINE: Good morning.

WERTHEIMER: So this rover is considerably bigger than the two rovers, Spirit and Opportunity that landed on Mars in 2004.

PALCA: Yes. I was up at JPL, the Jet Propulsion Lab the other day and they've got some models and it's like the difference between a six-wheeled coffee-table and a six-wheeled compact car. The new one is about 2,000 pounds and the old ones were about 400 pounds.

WERTHEIMER: So the new rover, Curiosity, is nuclear powered? That's a change too.

PALCA: Yeah. Yeah, the Spirit and Opportunity were using solar cells and those are great because the sun was not going to wear out. And so, they could in theory go forever. The trouble is that Martian dust collects on the solar panels, and so the more dust you get the less power you get. On the other hand, a plutonium heat source doesn't matter what the weather is like outside. But then, of course, plutonium decays so after a while you don't get anymore heat, so you don't get any more power.

WERTHEIMER: How long do you think it would take plutonium to decay?

PALCA: Well, it takes a while. They're planning for a mission that's going to last two years. But I bumped into one of the scientists on the Spirit and Opportunity missions - or actually the chief scientist. And in that mission, they were saying, oh, I don't know if this is going to last more than 90 days - maybe three or four months. And he said to me the other day, he said, oh, these could go for decades. So I don't know. I guess they've got contingency plans for a long way out.

WERTHEIMER: The earlier missions to Mars, they were looking for signs of water, assuming that water is necessary for life. So this mission is looking for something else.

PALCA: Well, yes. It's looking also for water but instead of just sort of a hint of water, they're going to be able to look at rocks and say, Oh, this was a rock that had to form over X-millions or thousands of years in this kind of conditions, where there was a lake or stream. And maybe they'll be able to see sedimentary layers that were laid down with water coming in, and bringing in a flow of rocks and things, and then going out again.

And another thing, they have an instrument onboard that's going to look for organic compounds. These are the carbon-containing compounds that basically formed the building blocks of molecules that form the building blocks of life.

WERTHEIMER: When will we start to see some scientific results from Curiosity?

PALCA: Well, if you count pictures photos, those should be coming out fairly soon. But this is such a complicated piece of equipment that the engineers are planning to take several weeks - and possibly even in some cases months, I suppose - before they're going to turn on all the instruments on board. They really want to move slowly because this is an invaluable asset on the surface of Mars, and they don't want to do anything that might jeopardize its health.

WERTHEIMER: So, let's go back to the beginning. How confident are they that Curiosity can actually land on Mars and not be wrecked up from the get-go?

PALCA: Right. You know, that's such a hard question to answer. They are confident and they have done everything they can, but the history of landings on Mars is a checkered one. The U.S. had ones that haven't worked. The Russians have a lot that haven't worked. It's just a really, really hard thing to do. And while they are confident and they've tested and retested, and re-re-retested, something could happen that they haven't anticipated. Or something could just break and poof, it's all gone.

WERTHEIMER: And what would failure like that mean for NASA?

PALCA: Well, it wouldn't be good. We don't have the space shuttle anymore, so NASA is having to borrow or buy the launch services for its astronauts to go to the International Space Station. And there's no other big Mars missions on the books. There's a small one scheduled for next year. So there's a lot riding on this. And as the engineer in charge said, I feel like I'm on a $2.5 billion hot seat. And I guess he kind of is.

WERTHEIMER: That's NPR's Joe Palca speaking to us from NPR West. Thanks, Joe.

PALCA: You're welcome. Transcript provided by NPR, Copyright NPR.