GUY RAZ, host:

NASA's latest mission to Mars has just landed. The Mars Phoenix mission is designed to study the icy soil near the red planet's north pole. The idea is to see whether the conditions in the soil could possibly harbor some kind of life.

NPR's science correspondent Joe Palca is at the project's mission control at the Jet Propulsion Laboratory in Pasadena, California. Joe, how did it go?

JOE PALCA: Oh, Guy, it was just amazing. You know, when you draw something up on a blackboard and you say, okay, this is what's supposed to happen, like, you're playing football. You never really think it's going to happen like this. This thing went exactly according to plan. At every juncture when something was gonna happen, you'd wait about two seconds and people at mission control say, we see the signal for the heat shield warming up, and we see the signal for the parachute deploy, and we see the signal for the, you know, the radar detecting the ground. Unbelievable.

RAZ: Wow. I mean, it's not too often you see such a successful landing on Mars, right?

PALCA: Well, in fact this mission was killed. It was supposed to launch in 2001 and it was killed because two Mars missions, NASA missions failed in 1999. And so, yeah, you tend to get spoiled because the last two Rover missions, which were four years ago went, also went off perfectly. But the people here will tell you, this is an incredibly difficult thing to do. You've got to go from 12,700 miles per hour down to five miles per hour in seven minutes. And for that to happen, a lot of things have to work properly. And today, they all did. I mean, you just have to look at these guys faces and you say, they're like, they're pinching themselves. You know, they - in their wildest dreams they think, oh, well, it couldn't be this perfect and it turns out that it was.

RAZ: I - can just hear the excitement in your voice. When will NASA start receiving the data from this craft?

PALCA: Well, the amazing thing about this mission and about what's happening at Mars now is there's several - there's three spacecraft, working spacecrafts, currently orbiting Mars. Two of them were actually relaying signals, one in real time from the landing.

So they have some telemetry that already tells them that they've landed and they're only, they're tilt on the landing is only a quarter of a degrees. They don't have to worry about that. They haven't got any pictures yet, but they might get their first pictures in about 90 minutes from now when another pass of this orbiting satellite will relay the signal from the surface. The antenna on the Rover, on the lander, I'm sorry, is not strong enough to reach directly to Earth but with this boost it gets from the orbiting satellites orbiting Mars, they'll have data in about 90 minutes, and maybe a lot more in the next 24 hours.

RAZ: Amazing. Joe in the few seconds we have remaining, tell us a little bit more about the mission. What kind of instruments are on board?

PALCA: Well, this mission is supposed to do some, NASA has been very interested in studying water on Mars, the idea being that if you know what's happening in the water, you know whether there's a possibility that life once existed. The water that has been detected in other places has been very salty and very acidic, and they want to see if the water at the poles - which is ice, it's frozen water - but they can either find out whether it was very salty and acidic, maybe it was, maybe it wasn't. And they can also find out if it was ever something other than ice, maybe from the signals they'll detect whether it was liquid water that was flowing across the north pole at some warmer time in Mars' past. So, it's the search for water that could have harbored life. That's what they're looking for.

RAZ: Absolutely fascinating. Joe Palca, NPR's science correspondent at the Jet Propulsion Laboratory in California. Thanks for joining us.

PALCA: You bet.

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