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JPL podcast: Approaching the Red Planet

Feb. 24, 2006
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NARRATOR: Rolling out the red carpet at the red planet. I'm Jane Platt and you're listening to a podcast from JPL - NASA's Jet Propulsion Laboratory in Pasadena, California. Four NASA spacecraft are already working fulltime on Mars - the two long-lived rovers, Spirit and Opportunity, and two orbiters, Mars Global Surveyor and Mars Odyssey. And the European Space Agency has its Mars Express orbiter.

On March 10, they will all have a new teammate - Mars Reconnaissance Orbiter, launched August 12, 2005, and now zooming in toward the red planet. Today, we'll find out how the spacecraft will put on the brakes to maneuver itself into the correct orbit, and we'll learn what the mission will tell us about our rocky neighbor. Mars Reconnaissance Orbiter will beam back more data than all previous Mars missions combined, with several goals.

ZUREK: We're trying to understand the climate history of the planet and in doing that we hope to find those best places for future missions and we also hope to build on the past missions, bring all that detail together with new capabilities that this orbiter will take to Mars.

NARRATOR: Mars Reconnaissance Orbiter Project Scientist Dr. Richard Zurek of JPL. We'll find out more in just a couple of minutes about what Zurek and his colleagues hope to learn about the red planet. But before they can learn anything, a whole lot of things have to go right with the spacecraft as it nears the home stretch of its journey that began with a launch from Cape Canaveral on August 12, 2005.


ZUREK: The experience has taught us generally and me personally that you're not there till you're there. Getting into orbit around Mars has been difficult. We've lost spacecraft before at this juncture. In a way it's as critical as launch. When we blasted off from the Earth on our launch vehicle and got into space and on our way to Mars, that was a very nervous time, a critical event. Getting into orbit is very similar in that regard.

NARRATOR: Zurek's colleague at JPL, Mars Reconnaissance Orbiter Project Manager Jim Graf, says the whole team will be on edge during the final days and hours before Mars arrival on March 10.

GRAF: It's a very difficult time as we approach Mars because we've lost several spacecraft in this phase, so we have to be very diligent that we manage to make sure that we get everything done properly and that the spacecraft, the hardware and the software, all performs as we planned. To do that we're going to test, test, test on the ground here to make sure that we're ready to go.

NARRATOR: No matter how much testing is done, there is nothing like the real deal.

GRAF: It's a white knuckle period because the spacecraft has to do everything that we planned for it to do at the right time or else we won't fire our thrusters at the right time and we won't be able to get the reduction in our velocity that we're counting on, and that means we will not get into orbit.

NARRATOR: It's all one huge, tricky, super high-speed engineering maneuver.

GRAF: We're actually getting a little bit ahead of Mars, and Mars will have to catch up to us. So on March 10th Mars will be close enough to us as we come right by that it will start sucking the spacecraft down into the gravitational well, we call it, or into the gravity of Mars, and eventually we fire our thrusters, and that slows us down enough so the spacecraft can get captured by Mars.

NARRATOR: This Mars orbit insertion, or MOI, might sound like an exciting video game-but this is real life, and real space travel.

GRAF: It takes us about 12 minutes for a signal to leave Earth to get to the spacecraft and another 12 minutes to get it back here. So we can't joystick the spacecraft, we can't be going up and saying do this now and do that now, it has to be autonomous as we approach MOI, and the spacecraft has to make all of its own decisions.

NARRATOR: About 3 days before Mars orbit insertion, the team will load computer commands sequences. Then they start opening valves that feed the hydrazine propellant into the thrusters. Those thrusters are like jet packs to push the spacecraft into orbit around Mars. The final valves are opened just 35 minutes before the thruster burn. Adding to the drama of this highly critical time when the thrusters burn, the reassuring signal from the spacecraft that tells ground controllers everything's okay, will disappear for a while.

GRAF: The spacecraft will be in view of the Earth for about the first 20 minutes, but then the spacecraft goes behind the planet and we can't see it anymore. In fact, we have to wait another 30 minutes until it comes out from behind the planet for us to confirm whether we actually got the burn completed and got captured in orbit. That is going to be an extraordinarily tense time for all of us.

NARRATOR: Once the spacecraft pops out from behind Mars and sends a signal and confirms its health and position, the Mars Reconnaissance Orbiter team will breathe one huge, collective sigh of relief. But even then -- there's more stress ahead -- a six-month process called aerobraking. During that time, the spacecraft will slam on its brakes and slide smoothly into a low orbit above Mars. Well it's not literally slamming on the brakes and it's not a smooth slide.

GRAF: We actually allow the spacecraft to dip into the atmosphere of Mars. In doing so, it allows the friction that it has with the molecules in the atmosphere to slow the spacecraft down a little bit each time.

NARRATOR: This dipping process is repeated more than 500 times until the spacecraft ends up in a circular orbit, about 190 miles above Mars. But there are a lot of variables involved.

GRAF: The aerobraking process is black magic. Why? Because we know so little about the atmosphere of Mars. Mars is an enigma. We're going there to find out about the atmosphere and yet we're relying on the atmosphere to help us to get into orbit.

NARRATOR: And by the way, the two other current Mars orbiters, Mars Global Surveyor and Mars Odyssey, successfully used aerobraking. After Mars Reconnaissance Orbiter enters its final orbit, that's when the fun begins for Rich Zurek and the science team. They'll get a close look at the whole planet with their suite of six science instruments that will study the martian atmosphere, the surface and the subsurface. Two of the instruments are cameras--one to image wide swaths of the martian surface, another to capture high resolution pictures. Rich Zurek.

ZUREK: At the very highest resolutions we're able to zoom in to see things that are about the size of a coffee table.

NARRATOR: What are they looking for? Many things, but in particular, anything having to do with H2O.

ZUREK: We're looking at where water is in the atmosphere, where it may have been on the surface, and maybe even places where it breaks out onto the surface, gullies or these deltas that were formed in the past. And then we're looking for ice that is in the surface itself. We know there's ice from previous orbiters, in the topmost yard or so of much of the planet's surface. But what were looking for is whether that's just sort of the tip of the iceberg, if you will. We want to know how deep that goes, and that's what our radar will help tell us.

NARRATOR: So what's the big deal about water?

ZUREK: Water is essential if you want to understand the climate, it shapes the surface, the channels, the canyons. It's a powerful agent on Mars just as it has been on the Earth. For life, water is essential to life as we know it. So if you can find places where water has been, that may be the best place to look for evidence of whether life ever developed on the planet.

NARRATOR: And Jim Graf points out that Mars Reconnaissance Orbiter will help future missions to the red planet.

GRAF: Providing the fundamental data that will enable the success for future missions like Phoenix, which will be launching in 07, and like the Mars Science Laboratory, which will be launched in 09. But we can also find the right place for those landers to land and maximize their chance for finding water, perhaps finding life, finding the scientifically interesting things that we want.

NARRATOR: Final question for Rich Zurek: Why do people love Mars?

ZUREK: I could stand on that surface at Venus the surface is incredibly hot. You can't survive there. You could stand on the surface of Mars. You gotta be wearing a space suit, but you'd look up and you'd see a sky. There's sunlight that goes to the surface. It has a day that's almost the same as the Earth's, so that day and night progressions are the same. It has seasons much like the Earth - winter, summer, polar caps that expand. On Earth we'd call that the snowline. Those are very earthlike things, and it is a place that we can visualize humans going to explore.

NARRATOR: Today we've heard from two people on our planet--Dr. Richard Zurek, Mars Reconnaissance Orbiter project scientist, and Jim Graf, project mgr. More info on the mission is online at and . Thanks for joining us for this podcast from NASA's Jet Propulsion Laboratory.

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