Mars Dead or Alive (2004)

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Original PBS Broadcast Date: January 4, 2004

On January 3, 2004, a strange sight unfolded on the planet Mars. Above a vast, dry lake bed south of the martian equator, a conical vehicle parachuted toward the surface. Then, just before touch down, it was enveloped by a gigantic protective airbag allowing the craft to bounce safely to a stop. Inside was Spirit, the most sophisticated rover ever launched from Earth. "MARS Dead or Alive," which originally aired just hours after Spirit landed on the red planet, covers this mission in depth. The program's behind-the-scenes look at the construction of Spirit and its twin, Opportunity, includes a special up-to-the-minute segment with the latest news from Mars as of January 3, 2004—to learn if Spirit is ready to undertake the most comprehensive search for evidence of liquid water ever attempted on Mars. NOVA spent months documenting the tension-filled process of building, testing, final checkout, and launch of a pair of spacecraft that are designed not only to be remote-controlled field geologists but to perform in a demanding environment millions of miles from Earth. As the program shows, unexpected problems with designs for the parachute and airbags almost scuttled the mission, and a potentially catastrophic electronic problem on Spirit didn't turn up until the vehicle was completely inaccessible and awaiting launch.

Riding on the mission are not just the hopes of scientists seeking to answer baffling questions about the history of Mars, but the future of NASA's Mars exploration program itself. Twice in 1999 NASA probes arriving at Mars were lost without a trace. One of the few recent bright spots for Mars research was the surprising success of the experimental lander-rover Pathfinder in 1997, which was designed to test the airbag-landing technique.

Pathfinder was spawned by a freewheeling group of young scientists and engineers who are now back with the far more ambitious Spirit and Opportunity vehicles, which make up what is officially called the Mars Exploration Rover (MER) project. The MER science team is headed by planetary scientist Stephen Squyres of Cornell University, who conceived the project with the goal of probing the most burning questions in Mars science: Was there ever liquid water on the Red Planet? Were conditions ever suitable for life?

Spirit and Opportunity are mobile laboratories outfitted with visible-light and infrared cameras to scan the landscape and locate promising rocks for investigation; a power tool to grind off the weathered surface; a microscope to examine the interior; and two other instruments to sniff out the rock's chemistry. (For a closer look at a MER, see Anatomy of a Rover.) In this way, the MER team held out hope of finding evidence of the liquid water that many scientists theorize was once abundant on Mars's surface but has since vanished.

The landing sites were chosen for their strong signs of a wet past. Spirit is now on site in Gusev Crater, a possible former lake, while Opportunity has been exploring Meridiani Planum, where minerals have been detected that normally form in the presence of water. And where there's water, there may have been life. The ultimate goal of Spirit and Opportunity is to shed light on this intriguing possibility and perhaps pave the way for the most versatile explorers of all—humans.

Source: PBS


NARRATOR: On June 10th, 2003, a rocket took off from Cape Canaveral, Florida, its lone passenger, an explorer on a one way trip to Mars. His partner and identical twin followed soon after. They were born in California, endowed by a loving family with all the intelligence and skill humanly possible. But the explorers themselves are not human. They're robots designed to go places and do things that humans cannot. To their creators, though, they're much more than machines.

STEVE SQUYRES (Lead Science Investigator, Mars Exploration Rovers): The first time I stood there next to the rover and watched it drive, it brought tears to my eyes. You know, I try to be this steely-eyed space explorer dude, but that one just, I just couldn't take it. It was just too much, just seeing that. It was's, it's a phenomenal feeling.

NARRATOR: For centuries, Mars was an omen of war and disaster. Today, it's a destination, but still dangerous.

DAN MCCLEESE (Chief Scientist, Mars Program, Jet Propulsion Laboratory): We've lost about 50 percent of the missions that we've flown to the planet. It's a tough place to operate.

NARRATOR: But the attraction is irresistible.

GENTRY LEE (Chief Engineer, Mars Program, Jet Propulsion Laboratory): What's the single most important question that we're dealing with in space science? It's, "Are we alone?" When we go to Mars, the nearest and most likely place that life might have arisen elsewhere in this solar system, what we are really doing is, we are asking questions about who we are and where we came from. Maybe life evolved first on Mars and was knocked off the surface and carried to the Earth. Maybe we're all Martians.

NARRATOR: If so, the proof is out there. But first, our explorers must survive the most dangerous part of the journey: landing on Mars. Tonight, NOVA presents an exclusive, behind-the-scenes chronicle of this great adventure. And when the first rover touches down, we'll bring it to you as it happens: Mars Dead or Alive, right now on NOVA.

Major funding for NOVA is provided by the Park Foundation, dedicated to education and quality television.

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NARRATOR: It's the summer of 2002, and, as usual, Steve Squyres is on the road. He's a professor of astronomy from Cornell University in Ithaca, New York. In the past few years he's logged almost a million miles commuting to NASA's Jet Propulsion Lab, JPL, in Pasadena, California. This is where NASA builds spacecraft to explore the solar system, and at the moment they're building two of the most sophisticated ever attempted: twin rovers designed to unravel the secrets of Mars. These robots are the ultimate custom machines, no stock parts, nothing off the shelf.

JIM COLVIN (Rover Engineer): This isn't General Motors, and we're not building pickup trucks. This stuff that you see here has never been built before.

NARRATOR: A year before launch, the rovers and science instruments are bits and pieces of hardware scattered through a dozen different buildings. Steve Squyres is the lead scientist and a driving force behind the mission. But the engineers will make it happen. More than 600 people at JPL are dedicated to M, E, R, Mars Exploration Rovers. It's a demanding job with an unusual payoff.

ART THOMPSON (Rover Engineer): I think it's easy to forget about the big picture when you start getting a little tired, a little burned out. Then you start thinking, "Why am I complaining? I'm going to work to drive a vehicle on another planet."

NARRATOR: And not just any planet. Mars has tantalized us for centuries with a confounding mix of the familiar and the bizarre: canyons miles deep and thousands of miles long; a volcano the size of Arizona and three times the height of Mount Everest; what water there is on the surface is frozen at the poles. There's evidence of more ice underground, but so far, not a drop of liquid anywhere. It's a frigid, almost airless desert of dust, wind and radiation. Even for a robot, it's a hostile environment, but these rovers will be prepared for the worst.

STEVE SQUYRES: They're going to be in a place where there's dust to get in the joints and the temperature goes through 100 degrees Centigrade between nighttime and daytime. But this was the world that they were designed for. And so, I, I think they're going to do okay.

NARRATOR: The lure of Mars is the possibility that it wasn't always such a harsh and barren place. From orbit we see ancient signs of water flowing across the surface, which could mean that Mars was once warm enough to be wet and perhaps a habitat for life.

STEVE SQUYRES: Just because there was liquid water there, doesn't mean that there was life there. But we cannot imagine life without liquid water, so it's a necessary condition.

I want to go to two places on Mars where we've got good evidence that water was there, and I want to answer the question, "Was this an environment that would have been suitable for life?"

NARRATOR: The rovers will be field geologists, reading the story of early Mars recorded in the rocks and minerals. Scientists on Earth will send instructions. But even at the speed of light it will take 10 minutes or more for radio signals to reach Mars, so the rovers will have to be smart enough to make many of their own decisions, like how to navigate around hazards. They'll have high resolution, stereovision to survey the landscape, plus an infrared camera called Mini-TES to locate minerals that formed in contact with water. More science instruments are on the robotic arm. There's a power tool to grind off the weathered surface of a rock, two spectrometers to sniff out what it's made of, and a microscope to examine its interior. It would be hard enough to make all this work on Earth, but to make it work on Mars will be extraordinarily difficult, and the engineers have just 12 months left to pull it off.

Today the instrument called Mini-TES is scheduled for a test. Because it can detect minerals that formed in contact with water, it may be the single most important instrument on the mission. They have to prove that this delicate piece of hardware is tough enough to survive the shocks and bumps it will experience on the way to Mars. It will be bolted to a slab of aluminum, which will then be struck by a gas-driven hammer, giving the instrument a severe jolt. Steve wants to make sure the engineers don't overdo it and break the instrument.

STEVE SQUYRES: NASA ultimately holds me responsible for delivery of the scientific instruments on the payload. Now, I'm not an engineer, but I take my responsibilities very, very seriously. And if we break some hardware, you know, it's going to be my neck on the line—along with a whole bunch of others.

JAMES NEWELL: If we break this today...

STEVE SQUYRES: ...five million dollars.

HO-JIN HUANG (Test engineer): Oh, five million dollars?

JAMES NEWELL (Test engineer): ...and maybe no flight.

STEVE SQUYRES: Let's make sure everybody's clear on what we're doing here. This is an irreplaceable flight unit.

NARRATOR: Steve is worried, because the point of this test is to prove that the instrument is tougher than it needs to be—what engineers call "margin." But such tests are not usually done on the actual hardware going to Mars.

STEVE SQUYRES: What we wish we had was an engineering model, which is another copy of the flight instrument, identical design, but not one that's going to Mars...put it on the table, shock it. If it survives, it means the design's okay; we don't have to do it to the flight units.

NARRATOR: But at $5,000,000 apiece, they could only afford to build two, one for each rover. A mistake here could cripple one of them and not leave enough time to recover.

STEVE SQUYRES: That's what I'm trying to get at. Is there something we can break inside this instrument today that's going to cost six months to fix? Because if it is...

NARRATOR: The engineer who knows the instrument best is Steve Silverman from Raytheon. Squyres wants to know if he thinks it can survive this severe jolt or if they should insist on a less dangerous test.

STEVE SQUYRES: Look, do we do the test today?

STEVE SILVERMAN (Technical Director, Planetary Systems, Raytheon): I called the dynamicist, and he said we should be able to survive it. Now, will we? I can't answer that one, Steve.

STEVE SQUYRES: I'm not asking for a prediction, okay? I'm asking for, I mean, if it's a binary thing...Either we do the test today or we don't do the test today. What's your recommendation? Do we strap it to the table and shoot the thing off, or do we walk out of here with our instrument?

STEVE SILVERMAN: This is a tough one.

STEVE SQUYRES: We can, we can cause all sorts of hell for a lot of people today, but we can't bring this whole project down.

There's a natural built-in creative tension between the science and the engineering. And ultimately, even though it gets people kind of riled up sometimes, it works to the benefit of the system.

Okay, so, and your recommendation is?

STEVE SILVERMAN: I think we go. If the project is going to require a qualification test we should do it now.


STEVE SILVERMAN: Because if we're going to break it...

STEVE SQUYRES: If we're going to break it, we ought to break it as soon as possible.

NARRATOR: Finally, the moment of truth.

CONTROL ROOM SPEAKER: 5, 4, 3, 2, 1...

NARRATOR: No one will breathe easy until the results are in. Steve has to move on to other business, leaving the post-mortem to the engineers.

STEVE SILVERMAN: If the current's good, we're in business.

GREG MIEHALL (Engineer): Current looks good.

STEVE SILVERMAN: Whew! We survived the shock. All right! Someone call Squyres.

GREG MIEHALL: Hey, Steve, wanted to give you the good news. We turned on Mini-TES 1. It's working great. It survived the shock test, so we're pretty happy. So, thought you'd like to hear it. Have a good flight. See you. Bye.

NARRATOR: He needs all the good news he can get. The clock is ticking, and Mars waits for no one. Every 26 months, the orbits of Earth and Mars bring the two planets to a brief, relatively close encounter, about 35 million miles apart. This is when missions must be launched, and the next opportunity is rapidly approaching. If they miss it, they may not get another chance, since it would cost millions to put everything on hold for two more years.

And that's not all that there is to worry about. Everyone remembers what happened the last time NASA tried to go to Mars. In 1999, a mix-up between English and metric units resulted in the loss of an orbiter. Just a few months later, a software problem caused a lander to crash. Mars is a graveyard for half the spacecraft ever sent there. But this time they have to succeed.

STEVE SQUYRES: I think the credibility of the Jet Propulsion Laboratory is at stake. I think that the credibility of NASA's Mars Program is at stake. A hell of a lot of science is at stake. The last 10 or 15 years of my career is at stake, from a purely personal perspective. There's an enormous amount at stake here, and everybody realizes it.

NARRATOR: Ten months before launch, the engineers are feeling the pressure. They've been working around the clock to complete an engineering model of the rover. It has no instruments or solar panels yet, but otherwise it's identical to the ones that will go to Mars.

RANDY LINDEMANN (Rover Systems Engineer, Jet Propulsion Laboratory): There are several thousand unique pieces of hardware, each one precisely placed, but never perfectly placed. It's really freaking hard!

NARRATOR: Today is the first in a long series of tests to find out if the rover can perform its most basic functions.

DANIEL LIMONADI (Rover Engineer): Joel, whenever you're ready, go ahead and send the command.

JOEL KRAJEWSKI (Rover Engineer): Command sent.

RANDY LINDEMANN: With that very first test, when we first see it happening, that technical part of your brain says, "This has to work." That emotional part of your brain is saying, "Yeah, but what did you forget? You're not as smart as you think you are." And let's just say we never get past that fear until we're successful.

NARRATOR: Wheels turn for the first time, and suddenly Mars is much closer.


STEVE SQUYRES: We just saw a MER rover move. It just came to life for the first time, today, in front of us. I mean, we're still under pressure, but we're doing it. You know? We're actually doing it. We're building stuff, we're driving stuff, we're taking pictures with the cameras, we're moving the arm and it's working. The morale right now is the highest I've seen it since the start of the project. We're just flying.

NARRATOR: But the rover will have to get a lot more sophisticated if it's going to survive on Mars, and the biggest challenge will be the last six minutes of the journey.

STEVE SQUYRES: During entry, descent and landing, the rover is on its own, okay? There is no back and forth between the vehicle and Earth. We've taught it what to do, and it does it or it doesn't.

NARRATOR: Atmospheric friction will slow the spacecraft from about 12,000 to 900 miles per hour, then a parachute takes over. The heat shield falls away, and the lander descends on a long bridle. Now the rover inside keeps track of the altitude with radar. At 900 feet a cocoon of airbags inflates around the lander. Just seconds before impact, reverse rockets fire to soften the blow, and then...

STEVE SQUYRES: They bounce, they bounce, they bounce, they bounce, they bounce, they roll, they bounce, they roll, they bounce. And that can go on for quite a while. I mean we can roll and bounce, like, a kilometer.

NARRATOR: The landing sites have been chosen with safety in mind.

STEVE SQUYRES: But I can't tell you that somewhere in the middle of that there isn't a five-meter-tall, pointy, sharp rock, that if you just happen to have a bad day, you land on, pop your airbags, and that's it. There is an element of luck about it.

NARRATOR: Still without help from Earth, the rover has to unfold itself and call home to say, "I've arrived."

STEVE SQUYRES: Every one of those events is, is triggered by the computer. There are electrical signals; there are things that have to fire. There's mechanical stuff that needs to work—any one of those events fails for whatever reason and we're done. So there's a lot of things that can go wrong, and on landing day we're going to hope it all works.

NARRATOR: Of all the things that could go wrong, the airbags seem the least likely to cause trouble. It's a relatively simple idea: inflate a cushion around the lander and let it bounce. To test the bags properly, they have to duplicate the atmospheric pressure on Mars, which is less than one percent of the atmosphere on Earth.

For the first test, they go to the world's largest vacuum chamber, at a NASA facility in Ohio. When the chamber is pumped down to a near vacuum, they'll inflate the bag and drop it on a platform studded with sharp rocks to simulate landing.

TOM RIVELLINI (Landing Systems Engineer, Jet Propulsion Laboratory): We went out to Ohio, and we were ready to do these great and glorious tests and show everybody that hey, things are going to work. Don't worry about this, guys.

ADAM STELTZNER (Landing Systems Engineer, Jet Propulsion Laboratory): So we're all sitting in a control room, and we've got a half-dozen video cameras looking at all sorts of different angles. Everyone's sitting around saying, "Oh, I think we'll be good." And we drop... the airbag comes down, it hits the ramp, and as it's bouncing off the ramp you see this huge gaping hole in one of the airbags. Whoa! What's happened here? This is unexpected.

TOM RIVELLINI: It was a frightening moment. We all believed that we could make it happen, but all of a sudden we didn't know how it was going to happen, and we really had to rethink everything.

NARRATOR: They were caught by surprise because they'd done this all before, on a highly successful mission from 1997 called Mars Pathfinder. Its purpose was to demonstrate what was then a radical new concept: a controlled crash landing with an airbag and a fold-up lander inside carrying a small rover. Pathfinder didn't produce a lot of science, but it did prove that the landing system and rover worked on Mars. It worked so well, NASA decided to use the same technology for MER.

ADAM STELTZNER: Go with what you know. We had a success. Take the drawings off the rack for Pathfinder, build a new set. Except Pathfinder got dinged for not having enough science return, so we're going to up the science return by stuffing a big rover inside of this lander.

NARRATOR: MER is the Pathfinder rover on steroids. It has bigger wheels and suspension to handle rougher terrain. It carries all the cameras, radios, antennas and the computer that runs everything—which on Pathfinder were all part of the lander—plus the payload of science instruments and the robotic arm, all of which require more power, meaning bigger solar arrays, more electronics and a heater to keep things warm at night. It's the ultimate off-road, off-Earth, mobile science laboratory.

And yet, because of space limitations on the launch rocket, this pumped up rover must fit into the same size package that carried Pathfinder to Mars. And that's a problem. The solution is a complex, fold-up rover that will have to unfold itself after a long, cold, rough trip to Mars. And the whole thing weighs 50 percent more than Pathfinder, which is an even bigger problem.

With the airbags struggling to handle the extra weight, it's even more important now to get the best possible performance from the parachute to control the velocity when the lander hits the ground. The first parachute strength tests will tell them where they stand. The chute will be deployed from this giant dart as it's dropped from the helicopter.

ADAM STELTZNER: We go to these first tests...beautiful day...we're very confident.

NARRATOR: On Mars the parachute will open at more than 900 miles per hour. But in the denser atmosphere of Earth, the same stress on the chute can be achieved at a much slower speed.

TEST CONTROLLER RADIO: 5, 4, 3, 2, 1...

ADAM STELTZNER: Here we go. Here we go, baby! Oohh!

We have this massive structural failure; the parachute rips apart. And we are all kind of stunned. First the airbags, then the parachute...and it sets in on us that we're going to have to find, magically find time in our schedule for a redesign cycle and prove that we have the entry, descent and landing system that will take us to Mars.

TOM RIVELLINI: All of a sudden, your whole world becomes that tear, that rock. Why did that happen? How do I fix that? What are we going to do? And the whole mission is riding on fixing those kinds of problems. It's a terrifying moment, but at the same time, it's, it's exhilarating.

ADAM STELTZNER: There are moments when there is an at-all-costs component to the effort. And it can get you down. You can find yourself eating a lot, drinking too much. And it's really an important practice to keep on top of the stress. I'm exercising more than I've exercised in my entire life. I'm working out once a day, at least, because if I don't I go crazy.

NARRATOR: Landing on Mars has never been easy.

GENTRY LEE: The Russians tried seven times to land on Mars, before we ever did. One spacecraft lasted for a few seconds. All the rest were failures. If it were easy to land on Mars, people would be doing it all the time.

NARRATOR: Before Pathfinder, the only successful attempts were the Viking landers in the 1970s. It was NASA's Golden Age, with powered landers, ten years of development, and four times the $800 million budget of MER.

GENTRY LEE: It was $900 million dollars in 1973 dollars, which is $3.5 billion today.

NARRATOR: The Viking orbiters produced tens of thousands of pictures, a complete photographic map of the planet. But a primary mission of the landers was to look for signs of life on the surface, and that search came up empty. What Viking did find is a distinctly unfriendly environment for life: a hundred and fifty below zero at night, very thin atmosphere, no protection from solar radiation, no organic chemicals in the soil, no liquid water. The verdict, at the time, was that Mars is dead.

DAN MCCLEESE: The search for life dominated all of the public and governmental interest in the mission. And when life was not found by Viking, then it was a disappointment, and we had no Mars missions for 20 years as a consequence.

NARRATOR: This time the strategy will be different. The dried up river channels seen from orbit suggest that Mars was not always as barren as it now appears. Scientists can imagine an early Mars where liquid water flowed across the surface, forming lakes and even oceans. On Earth, wherever there's liquid water, there's life, even in the most hostile environments like hot springs, beneath arctic ice, and deep underground. In the search for life on Mars, NASA's current strategy is to follow the water.

DAN MCCLEESE: If we can find the places on Mars where water pooled, then that's where you want to go. That's where you want to look for life. So water is, if you will, the scent of the life that we're looking for.

NARRATOR: There are many places on Mars that may once have been wet, but only a handful where the rovers can actually go. They're solar powered, so they need to be near the equator where the sun is almost directly overhead. And within this narrow band they can land only at the lowest elevations, where the parachutes will have enough time in the thin atmosphere to slow the landers before they hit the ground. That eliminates 95 percent of the planet, and much of what's left is too dangerous for landing or for operating the rovers. After two years of investigation they're down to a small handful of possible landing sites.

MARK ADLER (Deputy Mission Manager, MER): All right, we can get started. Right now we're a week behind in selecting our wind-safe sites, so...

NARRATOR: This is where it gets difficult.

STEVE SQUYRES: Believe me, these sites are not all created equal, from a science perspective. Some are very exciting, some much less so. And they're going to be chosen largely on the basis of their safety. Scientifically this site has nothing going for it.

PETE THEISINGER (Mars Exploration Rovers Project Manager, Jet Propulsion Laboratory): You all understand the threat I'm trying to protect us against, right?

There's this natural tension between the scientists and the engineers, because the engineers are the ones who have to tell the scientists, "the possibility of failure, if we do what you want, is too high."

NARRATOR: One site they can all agree on is called Meridiani Planum. It looks relatively safe, and orbiters have detected a large deposit of the iron mineral, gray hematite, which on Earth usually forms in the presence of water. But the scientists want very badly to try something more adventurous for the other rover.

STEVE SQUYRES: There's a place called Gusev Crater, a big impact crater, maybe 100 miles or something across. And it's got this huge dried up river valley flowing into it. It's hard to believe that this thing didn't have a great big lake in it at some point in Martian history. Sediments are going to be deposited in that lake. You should have a good sedimentary record of liquid water and whatever was going on there, so Gusev Crater is a fabulous place to go.

NARRATOR: But Gusev may have strong winds, and that presents a serious hazard for landing. Just before impact, reverse rockets will fire for a few seconds to reduce velocity to something the airbags can handle. But if the wind is blowing the lander along horizontally—relative to the ground—or causing it to swing when the rockets fire, the lander could hit the ground with too much horizontal velocity and potentially disastrous results. The engineers have added another rocket system to counteract some of that sideways velocity, but it may not be enough to handle a worst case scenario at Gusev Crater.

PETE THEISINGER: The engineers know that the science team wants this site. And we want to go where they want to go. But we will not go where it's too dangerous to go.

NARRATOR: The final decision will be made at NASA headquarters. But for Gusev to be an option, the engineers will have to get maximum performance from the problematic airbags and parachutes.

ADAM STELTZNER: We're working nights and weekends to try and get that job done. We're really pushing to try and make this Gusev site work for the scientists.

NARRATOR: The airbags have been redesigned with a loose secondary bladder inside. Like the inner tube of a tire, it's isolated from the outer layers, which absorb most of the stress. The new design has survived a series of punishing tests up to the equivalent of hitting a pile of rocks at 50 miles per hour. This bodes well for the prospects of going to Gusev Crater.

But unless the parachute problem can be solved, they won't be going anywhere at all.

ADAM STELTZNER: Currently this project does not have a parachute design that works. That's not a good place to be in.

NARRATOR: They've moved to the wind tunnel at NASA Ames, near San Jose, California. This 135,000 horsepower wind machine will make it possible to test more parachutes in less time than the helicopter method, and time is the enemy. Since the failure of the first test, the landing team has been searching for ways to make the parachute stronger. Simply using heavier fabric won't do it. There's no more room in the canister for thicker material and there's no room on the lander for a bigger canister.

ADAM STELTZNER: Because we can't fit any more parachute, what we have to do is take a smaller parachute: thicker fabric, but less square yards of fabric.

NARRATOR: But this creates problems. If they shrink the diameter too much, there won't be enough drag to slow the lander down. An alternative is to shorten the band, but the band controls stability. If it's too short it could make the chute more vulnerable to wind. It takes weeks to build a parachute, so, with time running out, they've come to the test with several design variations, hoping that one of them will work.

ADAM STELTZNER: This test is the big deal. If we have a failure here, that's going to start a measure of desperation we never want to find ourselves in, so...

NARRATOR: The first chute will be fired from a mortar on top of the tower when the wind is up to speed.

TEST CONTROLLER: 5, 4, 3, 2, 1, fire!

WAYNE LEE (Entry, Descent and Landing Systems Engineer, MER): Hello? That's strange.

NARRATOR: This was not in the plans. The chute fails to inflate, a phenomenon known as "squidding." Instead of solving a problem, they've uncovered a new one, and they don't know what's causing it.

ADAM STELTZNER: This is super, super, super, mega...this is super, megabummer. Just when we thought we were there, just about to cross the finish line, out of nowhere this thing comes. It certainly was the worst feelings I'd had thus far in the project.

NARRATOR: In 30 years of testing this type of chute, from Viking through Pathfinder, squidding has never been seen before.

ADAM STELTZNER: It looks like it...we'd expect it to just go now. Come on! Go now!

The parachute is displaying that it has a personality disorder. In a situation like, this you need to think about all the possible solutions. And then you have to get moving down all of those solution paths, because you don't know which one is going get you out of the woods.

JUAN CRUZ (Landing Systems Engineer, MER): Okay, I need a favor from you.

NARRATOR: They can't prove the strength of the new parachutes until they find and correct the cause of the squidding.

ADAM STELTZNER: This is a bit of a ghost. By the end of this week, it could be an unpleasant memory. Or it could stay with us, and be a very, very serious problem that we might not really have a solution for.

MARK DAVIS, NOVA PRODUCER: What happens if you don't get a solution for it?

ADAM STELTZNER: Well, it would be dramatic, but this could be a mission-ender.

NARRATOR: The next day the bosses arrive from JPL. They've been through this before, so no one is panicking yet.

ROB MANNING (Systems Engineering Manager, MER): Every one of our missions seems to have some sort of grand challenge in the final year before launch. It just seems to be part of the deal. I guess it's because we don't do this often enough. It adds to the stress levels, especially since Mars is marching closer and closer. That launch date is coming closer and closer, and we have very little elbow room.

NARRATOR: To inflate, a parachute has to trap more air than it lets out. Air flows in from the bottom, and some is allowed to escape through a vent at the top and the gap above the band. But if too much escapes the chute won't fully inflate. In theory, it's simple. But in practice, parachutes are a nightmare for engineers. The physics of inflation are complex and hard to predict. To figure out what's going on here, they'll have to run some experiments. They start with the simplest possible solution on the failed parachute: they'll make the vent hole smaller and try again to inflate the chute.

ROY FOX (Parachute Designer, Pioneer Aerospace): We've tacked this restrictor inside the vent of the canopy, and I'll lay it out here now.

NARRATOR: The chute can't be repacked and fired from the mortar, so they tie it closed at the bottom, crank up the wind, and hope for the best. When the tunnel is up to speed, they release the line holding the chute closed. Incredibly, the culprit is exposed on the first try. This parachute was mistakenly built with an oversized vent. Now that the chute is inflated they can see that the strength problem has been solved. But they're not done yet. It will take another month of work to arrive at the final design.

ADAM STELTZNER: Look at that thing fly. It's beautiful, absolutely beautiful.

NARRATOR: Just days before their deadline, the parachute team has found the ideal combination of strength and stability.

ADAM STELTZNER: A perfect inflation and a perfect handling of the loads, by our most desirable...At a system level, this is our most desirable parachute.

WAYNE LEE: What this means now is that the scientists are going to have a shot at getting to that Gusev Crater landing site.

ADAM STELTZNER: And that's the number one science site.

NARRATOR: The landing site decision is still months away but the airbags and the parachute are ready for Mars. It's five months until launch. The rovers are almost ready to go, the hardware at least. The software is another story.

STEVE SQUYRES: The software for launch, cruise, entry, descent and landing, getting down on the surface, that is in good shape. But the software for driving around on the surface and doing the science is still kind of shaky right now.

NARRATOR: There simply isn't enough time to teach the rover everything it needs to know before launch. So they'll keep working on the software and then reprogram the computers by radio when the rovers are on their way to Mars.

STEVE SQUYRES: You can send the vehicle, and then you can launch the software off into space six months later.

NARRATOR: The engineers are doing all they can, but soon, their rover will be on its own.

RANDY LINDEMANN: I hope it's not a rebellious teenager. And I'm hoping that the environment we put it in challenges it—because that challenges us—but doesn't challenge it too much.

NARRATOR: Three months before launch, the rovers are on their way to Kennedy Space Center in Florida. It's the first leg of a journey that will end on Mars. At the launch pad, preparations are underway. The engineers carefully inspect the rovers one last time, and they find a problem: a faulty circuit board inside both rovers. To replace them they must open the solar panels by firing explosive fasteners called pyros, of which there are dozens on each rover.

STEVE SQUYRES: The rover's solar arrays were already fastened together. Everything was all fastened up tight, they were ready for launch. We had to open them up again. The only way to do it was by actually firing live pyros. Bang, bang, bang.

NARRATOR: With the panels open, the problem is easily fixed. New boards go in; the panels are closed up again and secured with fresh pyros. But just three weeks before launch the engineers discover that pyros can sometimes short circuit when fired. And a short might have overheated components called resistors in the pyro-firing circuits, compromising their ability to fire pyros on Mars.

STEVE SQUYRES: What we're worried about is the possibility that these resistors could have been heated to the point where they have been destroyed, and next time we use them, at Mars, they might not work. And we have no way of getting at them and testing them. The rover is ready to go to the launch pad. It would take weeks to take the thing apart, and it would blow our schedule. We wouldn't be able to launch. This could threaten the whole mission. I mean, these things, the rovers, could end up in the Air and Space Museum over this, okay? If we're not able to launch these things now, it may not make sense to ever fly them.

NARRATOR: The only way to prove that the rovers are okay is to test all the pyros that were ever fired and see if any of them has a short circuit.

STEVE SQUYRES: If it's not shorted out, pyro's fine. You're ready to fly. If you find it, and it's got a short circuit in it, then you've got trouble.

NARRATOR: The problem is, no one expected to need those fired pyros again. Now they have to find them.

STEVE SQUYRES: And so there was this treasure hunt. And people were going in bags and shelves and pulling things apart. And gradually, piece by piece, they were found. The last one, the critical one that we needed to prove that we were really okay was found yesterday. Three days before launch, and we're still sweating these resistors. It was, it was awful.

NARRATOR: On June 10th, rover number one is finally cleared for launch. And it now has a name: Spirit. The landing team has delivered what the scientists asked for: a system capable of handling Gusev Crater, the site chosen for Spirit by NASA Associate Administrator, Ed Weiler.

ED WEILER (Associate Administrator, NASA): Being the end of the food chain on this thing, and being the one that if something goes wrong, is the one ultimately going to have to explain to Congress why it went wrong, it's one of the honors of being an Associate Administrator. It's a scary mission. There's a lot, there's an awful lot of things that have to work just right in the entry; and the descent and the landing are the ones that really worry me. If we get on Mars and get that thing moving, I think we'll be just fine.

STEVE SQUYRES: I'm not nervous, man. I'm ready to fly. It's been a long time coming. Today's the day. We're heading to Mars, maybe today, maybe a few days depending on what the weather does to us, but it's time to fly.

NASA VOICE (launch controller): NASA C-E is go. S-M-E is go.

NASA VOICE (George Diller, Kennedy Space Center): Fifteen seconds.

ADAM STELTZNER: Got to remember to breathe, got to remember to breathe.

NASA VOICE (George Diller, Kennedy Space Center): Ten seconds, 9, 8, greenboard...

CROWD OF SPECTATORS: 7, 6, 5, 4, 3, 2...

NASA VOICE (George Diller, Kennedy Space Center): Main engines start, and liftoff of the Delta 2 Rocket carrying the Spirit...

ADAM STELTZNER: Yes! All right! Beautiful!

NARRATOR: A month later it's a night launch for rover number two, now called "Opportunity." A series of problems with the rocket has consumed almost two weeks of the launch window. Only one week remains, after which Mars will be out of reach for another two years. But tonight, everything looks good. Bagpipers from Cornell will provide a musical sendoff.

STEVE SQUYRES: Don't worry, you'll see it. It's just about ready.

NARRATOR: For Steve and his family, it's been a long wait.

STEVE SQUYRES: Twenty seconds, here we go...

Hold! Hold! 15 seconds!

NARRATOR: A glitch in the fuel system stops the countdown. Armed for launch, the rocket is now, literally, a bomb. Over several very long minutes, the launch crew manages to pull it back from the brink.

STEVE SQUYRES: Seven seconds!

NARRATOR: The fuel problem is also resolved, and a half hour later they're ready to try again.

STEVE SQUYRES: I was so sure last time. I don't know what to think this time.

NASA VOICE (George Diller, Kennedy Space Center): 10, 9, 8...

STEVE SQUYRES: 7, 6, 5...Here we go. God! Come on, baby.

NASA VOICE (George Diller, Kennedy Space Center): ...4, 3, 2, 1. Engines start, and liftoff of the Delta Rocket with Opportunity.

STEVE SQUYRES: It's hard to say goodbye. I'll see them again in pictures, but I'm never going to lay my eyes on them again. But hey, you know, they've got to do what they've got to do.

NARRATOR: Seven months later, it's landing day: January 3rd, 2004. The rover Spirit is due to touch down in Gusev Crater at 8:35 p.m., Pacific Time. In Mission Control at JPL, the landing team braces for the most dangerous six minutes of the journey.

STEVE SQUYRES: We're landing on Mars. You know, the thing is 100 million miles away, two-thirds of the spacecraft that have ever gone there have died. So yes, it's dangerous.

ADAM STELTZNER: The team has worked very, very hard, and there have been some fairly significant sacrifices. And so, we're really hoping for a payoff.

NARRATOR: At 8:14 p.m., they pick up a faint signal that the landing capsule has separated from the cruise stage. As the animation shows, the rover is now on its own. And the mission controllers are just spectators. At 8:29, the capsule hits the top of the atmosphere. A few minutes later, the parachute opens, the lander separates, air bags inflate, rockets fire and the lander is cut loose.

WAYNE LEE (Landing Systems Engineer, MER): So, roughly any signal that we receive from now indicates the vehicle would be alive, on the ground and bouncing. Stand by.

NARRATOR: Now they wait for a sign that the rover has survived. But suddenly, the signal is gone.

WAYNE LEE: We saw an intermittent signal that indicated we were bouncing, however, however, we currently do not have signal from the spacecraft.

NARRATOR: Minutes pass. Finally, at 8:51, Spirit calls home.

STEVE SQUYRES: It's an amazing night, man. If things go well, we're going to see Gusev Crater, our new home, in just a couple of hours.

NARRATOR: Just hours after landing, Spirit is not only safe on Mars, it's hard at work sending home pictures. Within days, the high resolution camera sends back the first color postcard of the Martian landscape. A new era of exploration has begun.

Welcome to Mars.

The rovers are designed to look for evidence that the Martian surface once hosted liquid water, thought to be an essential ingredient for any possible life on Mars. What's so special about water? Find out on NOVA's Web site.

To order this show, or any other NOVA program, for $19.95 plus shipping and handling, call WGBH Boston Video at 1-800-255-9424.

NOVA is a production of WGBH Boston.

Major funding for NOVA is provided by the Park Foundation, dedicated to education and quality television.

We see an inventor. At Microsoft, your potential inspires us to create software that helps you reach it. Your potential, our passion.

Science: it's given us the framework to help make wireless communications clear. Sprint is proud to support NOVA.

And by the Corporation for Public Broadcasting, and by contributions to your PBS station from viewers like you. Thank you.

Source: PBS


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