Planning For 'Curiosity' On Mars

If all goes according to plan, the Mars Science Laboratory rover, nicknamed 'Curiosity,' will touch down on the red planet this weekend following what NASA has called 'seven minutes of terror' during the descent. NPR science correspondent Joe Palca and John Grunsfeld, head of NASA's Science Directorate, give a preview of the mission and talk about what scientists hope to learn from the latest ambassador to Mars.

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IRA FLATOW, HOST:

On the line with us now is Joe Palca, NPR science correspondent, out there at NPR West, out near sunny L.A., going to cover the Mars landing for us. Joe, are you?

JOE PALCA, BYLINE: Yes, oh absolutely, Ira. You know, we've done this a few times, haven't we?

FLATOW: I want to play a little bit of tape for you, Joe. You may remember this. I've got a little bit of tape from - if you're a longtime listeners, you may recall we were broadcasting live from the lawn of the Jet Propulsion Laboratory talking to Mars Pathfinder mission scientists waiting for word that the pathfinder had landed. And unexpectedly, this happened.

(SOUNDBITE OF ARCHIVED BROADCAST)

ROB MANNING: We have confirmed, we confirm that the spacecraft has now completed its final deployment, and we're transmitting our final semaphore on a low-gain antenna.

FLATOW: Oh, that's great.

MANNING: We now expect to get a signal on the spacecraft at 2:09 Pacific Daylight Time with real digital data.

UNIDENTIFIED WOMAN: My good.

FLATOW: Unbelievable.

MANNING: Stay tuned for more excitement from Mars Pathfinder.

(APPLAUSE)

FLATOW: Yeah, there's a little bit of excitement here in Pasadena, there really was.

Wow, it's exciting.

PALCA: I was incredible. And, you know, the guy who was speaking there, his name is Rob Manning, and he's now the chief engineer for this latest mission.

FLATOW: Is that right? Tell us what this is - what's supposed to happen here.

PALCA: Well, Sunday night Pacific Time, or Monday morning for you folks on the East Coast, at 10:30 or 1:30 a.m., Curiosity, which is way bigger than Pathfinder - I mean, Pathfinder, you know, they have a little model of it. It looks like a toy. It looks like it could have been made by Mattel or something. In fact, you remember Mattel did make a toy of the Rover.

But that was tiny, and this thing is the size of a compact car, still six wheels, They have that in common. This one is nuclear-powered, so no solar panels, so that makes it look different. And it's huge, and it's going to come down with this wacky new landing system they've come up with called the Sky Crane.

FLATOW: Sky Crane. Let me - let me bring in John Grunsfeld. He's a NASA astronaut and associate administrator Science Mission's Directorate at NASA. He joins us by phone. Welcome to SCIENCE FRIDAY.

JOHN GRUNSFELD: Oh, thank you very much, it's always a pleasure, Ira.

FLATOW: Joe's been describing what you've been calling seven minutes of terror. Why the movie-like thought about this?

GRUNSFELD: Well, there's a couple of reasons why, but there's actually a video online, it's gone viral, called "Seven Minutes of Terror," where folks from JPL who designed and built this system describe the entry, descent and landing. Just by comparison, when we enter on the space shuttle, it's 40 minutes. I wouldn't say it's 40 minutes of terror, but it's a relatively gentle event.

The Martian atmosphere is very thin. It's like our atmosphere at 100,000 feet. And so the entry, descent and landing phase happens much quicker. In fact, it happens in just a little over seven minutes. And so this basically Apollo-like capsule will hit the top of the atmosphere at 13,200 miles an hour and decelerate at up to 10 g's of acceleration, maybe 11 g's of acceleration.

And then there's a whole sequence of miracles that occur to put the Curiosity Rover safely on the surface, starting with this deceleration, which is guided. It actually has the intelligence of Neil Armstrong encoded in its computers to try and guide it safely into the place where we can then deploy a supersonic parachute, which will, you know, with a huge pull open up and, you know, start grabbing the Martian atmosphere to try and slow it below the speed of sound, to get it slow enough and close enough to the surface, and it will still be screaming towards the surface at a couple of hundred miles an hour so that eight rockets can fire to decelerate it so that we can get into a hover position to slowly let down, as you said, on a sky crane, a bunch of wires - slowly let down the rover, deploy the wheels and gently set it on the surface before we cut all those wires, and the sky crane can fly aside and crash into the surface.

And that whole thing takes about seven minutes. However, Mars is 248 million kilometers away, and so it takes about 14 minutes for the light to travel to Earth. So at the point that we get the first signals that the Curiosity system, the Mars Science Laboratory, is doing its thing, it will have already landed. And so the whole story, you know, also will take about seven minutes before we know the outcome.

FLATOW: What would - will you be able to watch it? I know there was talk about having one of the satellites overhead taking pictures of the descent in Rio.

GRUNSFELD: Also, we have - we've set up through maneuvers two of our satellites, the Mars Reconnaissance Orbiter and the Odyssey spacecraft, to fly overhead during the entry-descent landing phase, which is this critical, scary, sit-on-the-edge-of-your-seat phase, in order to listen to the signals coming from the Mars Science Laboratory spacecraft and eventually on the surface, the Curiosity rover. The Mars Reconnaissance Orbiter will be receiving the telemetry, and it's going to store it on board.

Odyssey will just turn it right around. We call it a bent pipe. It will receive the UHF signals and send it right back to Earth. So, again, with the speed-of-light travel time, we'll get information about what events are occurring, and very soon afterwards, the Curiosity rover will start sending pictures that it took on the way down, within, hopefully, hours, but it might be a day or so, so that we can see from cameras on an entry-descent imaging system what it looked like as it came down and as it was dropped down underneath the sky crane and set around the surface.

I mean, you know, it's going to go be kind of a slow-motion recovery of these pictures and data, but I know we're all going to be very anxious. But the first thing is just to find out from the basic signal, you know, when Curiosity says I'm OK, I'm on the surface.

FLATOW: Joe, you know, there are these fests going on all over the country, celebration Sunday evening...

PALCA: Yeah.

FLATOW: ...to go watch it as it comes in from - even Times Square is having it on...

PALCA: I swear...

FLATOW: ...the Jumbotron there or something.

PALCA: ...I couldn't believe it, and people say, oh, we want to see the movies that are coming out. I have to say I'm sorry. There's not going to be any movies. All you're going to see is a movie from - well, it's not going to be a movie, a live picture from the control room here at the Jet Propulsion Laboratory where you'll be able to see the commentary as it rolls in. But they will be looking at -as John Grunsfeld says, they'll be looking at data, not pictures at that point.

FLATOW: Let me just...

GRUNSFELD: We'll show the animations. We'll show the views of the control room and the people because after all, you know, this is a robot spacecraft. It's going - I mean, the amazing thing is we can build such a complex chemistry laboratory, virtual geologist, the size of, you know, an SUV, almost a ton of weight and get it to the surface of Mars, but it's a robot. It's the people here on Earth, the scientists that are going to make the discoveries using this robot.

And so, some of those people are going to be in the control room. They've spent, you know, their whole professional lives waiting for this moment, and certainly, the last five to six years working on the technology to get it there. So I suspect we're going to see a little bit of excitement. You know, we have the Olympics going on. You know, Americans winning gold medals, silver medals. Just participating is exciting. Well, this is more than the Olympics of science.

You know, this is well beyond that, I mean, getting Curiosity to the surface. And the public engagement is something that is very important to me because I see this as an opportunity to engage kids across America, in summer camps, at science centers, at museums and in Times Square...

FLATOW: Well, let me just - I have to engage our public and let them know...

GRUNSFELD: All right.

FLATOW: ...that this is SCIENCE FRIDAY from NPR, and I'm Ira Flatow talking with John Grunsfeld and Joe Palca. Sorry to interrupt because I...

GRUNSFELD: Not at all.

FLATOW: No. I agree with you. This is an amazing opportunity that - and I think it's unprecedented in NASA's outreach to the public to get it to Times Square in the giant screen under where the ball drops on New Year's Eve.

GRUNSFELD: Well, after all, New Year's Eve is the celebration of an astronomical event, one passage of the Earth around the sun. So it seems, why not use it for other astronomical events, like landing on Mars? But it's also, you know, Times Square is where famous things happen. It's where, you know, I'm sure, you know, folks were out there for Neil Armstrong. Now, they didn't have Jumbotrons, but certainly for the parades following the landing, you know, it's where we celebrate New Year's, you know, Apollo 13, all these kinds of events, you know - there, it was text going by, you know, probably at the CBS Building or something like that. But, you know, historic events, and this is a historic event.

FLATOW: Let me get - see if I can get quick call in before we take a break. Let's go to Michael in Philadelphia. Hi, Michael.

MICHAEL: Gentlemen, Mr. Grunsfeld, quick question, other than computer simulations, have you actually attempted to land something in a similar method, live, by having something orbit Earth and then come back so that you can actually watch this mechanism in action?

GRUNSFELD: Well, I think what you're asking is, have we tested all of the pieces to have this landing system, you know, tested out fully to land something on Mars? And the answer to that is this system is so complex and because we don't have a simulated Mars atmosphere, we've never actually tested all the pieces together. We've tested the parachute systems on similar conditions. You know, the sky crane operation, letting it down. You know, obviously, the rover, to drive it around and we have a rover here that's an engineering unit. But the scary thing about, you know, this, which is probably the hardest robotic entry we've ever done, and so there's a little risk, is we haven't been able to test it from start to finish altogether. So we tested it in piece parts. So we like to test as we fly, and this one's not quite there.

FLATOW: All right. We're going to take a break and come back and take some more of your calls if we can with John Grunsfeld of NASA and Joe Palca of NPR. 1-800-989-8255 is our number. We're talking about Curiosity's seven minutes of terror. I guess the terror is going to be in the control room.

(LAUGHTER)

FLATOW: Where they'll be biting their nails, and we'll all be biting our nails - what's left of them - by then, following along with them on Sunday evening. So stay with us. We'll be right back after this break. I'm Ira Flatow. This is SCIENCE FRIDAY from NPR.

(SOUNDBITE OF MUSIC)

FLATOW: This is SCIENCE FRIDAY. I'm Ira Flatow. We're talking about the upcoming landing of Curiosity, scheduled to land on the surface of Mars this weekend, Sunday afternoon. And in the couple of minutes we have left talking with John Grunsfeld and NPR's Joe Palca, Dr. Grunsfeld, give us some idea of what the mission is. We've talked about the landing, and what is the mission?

GRUNSFELD: So the hard part is getting it down. But once we're down, then we start the marathon of science with the Mars - with the Curiosity rover. And as I said, this is a chemistry laboratory we're sending. It's a, you know, geologist's dream. The rover is the largest rover we've sent, and it's going to try and look at the question of, you know, did Mars once have an environment? We know there were warm, salty water flows. We learned that from the previous rovers. And from orbit, we've seen minerals indicative in this Gale Crater where we're landing, that there was water flows. So the question is, when there was water on Mars on the surface, was it the kind of environment that would be conducive to the formation of life, microbial life, or habitable? And are there any hints, molecular hints, that there might have been life on Mars during that period?

And so we've picked this crater, Gale Crater, because it has the kind of stratigraphy, you know, the linear sedimentary rocks that we can see from orbit, that a geologist would go to to read back in geologic time. And so we'll be able to read back from essentially modern Mars all the way back, perhaps, three and a half billion years in Mars history. And sometime around two and a half billion years ago or so, some three and a half billion years ago, liquid water flowed on the surface. That's what we see. And during that period, you know, were the conditions suitable for life? And we can tell that from the minerals. And if there was life, there might be some kind of reduced carbon, some organic carbon signature tied up in the rocks, kind of a molecular fossil. Although nobody likes me to say the word fossil because it conjures up clams and trilobites, but we're not looking for that.

We're actually going to crush the rock, break it up, put it into a mass spectrometer and analyze the types of different minerals and the isotopic ratios of the individual elements. We also even have a camera with a laser on it than can zap a rock, briefly create a plasma, and in that flash, that vaporized flash, read the light back and tell what kind of mineral it is. So it's really the tools a geologist would have, even a hand lens imager, you know, like a geologist taking a magnifying glass up to the rock to look at the grains and tell what kind it is. So we're going to go out and explore, and this is real exploration.

FLATOW: Well, it all begins once you get down to the surface, and that's seven - after the seven minutes of terror.

GRUNSFELD: Yup. And it's going to take a few days to deploy the booms and the mast and get the cameras working and learn how to rove. You know, this rover has a little bit of a mind of its own, so we can tell it, hey, go to this place. Like the previous rovers before it, we have to learn how to operate it, all, you know, 250 million miles away.

FLATOW: Joe, can you give us any idea? Is tension building up of people anticipating, taking bets at all?

(LAUGHTER)

PALCA: Oh, yeah. No. Nobody - I don't think anybody is taking bets. You know, everybody has to deal with this in one way or another. They're trying to be relaxed. They're trying to be cool. But I mean, let's face it. As John Grunsfeld said, you know, you spend three or four, five or six years of your life building something, and it all comes down to these seven minutes. And it's just, you know, for the rest of us who work on things and then switch and work on something else, it's just really hard to fathom how much is riding on this and how anxiety-provoking it is. And, you know, really, there's not going to be any relief until about 10:31 Pacific Time on Sunday night.

And the sad thing is it could even be longer, because the communications is tricky, and if the bent pipe that John Grunsfeld was talking about - that satellite has been having some issues, and it might not be able to send a signal. I mean, everything is looking good now, but they could be fine on the surface and not know it for several hours. So there is another little twist to this story.

FLATOW: Yeah, well, get your sleep in now, because it could be a long night Sunday night. Thank you, Joe.

PALCA: You're welcome.

FLATOW: Joe Palca, NPR science correspondent. And thank you, Dr. Grunsfeld.

GRUNSFELD: Oh, my pleasure. Thank you very much.

FLATOW: And we'll be watching and having our fingers crossed for you.

GRUNSFELD: All right. Well, I hope the weather is good in Times Square.

FLATOW: Yeah. I hope it's good on Mars. He's a NASA astronaut and associate administrator for the Science Mission Directorate at NASA Headquarters.

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