Return to Transcripts main page

CNN Presents

Encore Presentation: Terminal Count: What it Takes to Make the Space Shuttle Fly

Aired July 15, 2001 - 22:00   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.


THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
LEON HARRIS, HOST: Think only astronauts have the right stuff? Before the space shuttle can reach the heavens, these guys have got to go through hell.

(BEGIN VIDEO CLIP)

QUESTION: What scares you the most about the job?

UNIDENTIFIED MALE: Screwing up.

(END VIDEO CLIP)

HARRIS: No room to work. No room for error.

An unprecedented look at an American icon: the space shuttle. From touchdown to takeoff.

Good evening and welcome to CNN PRESENTS. I'm Leon Harris.

Tonight, a space odyssey right here on earth. You have seen them streak into the heavens and return home time and time again, shuttle mission after shuttle mission. Easy as three, two, one, right? Not exactly.

Over the next hour, go where no journalist has gone before, as CNN space correspondent Miles O'Brien takes you into the belly of the beast, into those hectic and harrowing months between landing and liftoff.

With unprecedented access to the space shuttle hangar, here now is Terminal Count: What it takes to make the space shuttle fly.

(BEGIN VIDEOTAPE)

MILES O'BRIEN, CNN SPACE CORRESPONDENT (voice-over): It seems so familiar. So predictable.

UNIDENTIFIED MALE: About 7:40 a.m. today, the crew woke, they were served breakfast at around 8:00 a.m.

O'BRIEN: A crew of astronauts, anonymous to most of us.

UNIDENTIFIED MALE: Space Shuttle Discovery stands poised for liftoff from Pad 39-A.

O'BRIEN: A space shuttle on the launch pad.

UNIDENTIFIED MALE: This is not easy to do. You almost have to turn yourself into a pretzel to get in.

O'BRIEN: The launch team plugged in. And vigilant.

The milestones passing like -- well, clockwork.

It all looks so routine.

UNIDENTIFIED MALE: Well, they've been training as a crew for almost three years.

O'BRIEN: A ritual I knew by rote, or so I thought.

From my perch on the press mound, not far from the pad, I have confidently told the world about the latest departure of humans from our planet. It's my job.

I was cocky enough to think I knew the drill. But now, I know different. I asked the folks at NASA if they would show me what really happens between the launches, and after a good deal of convincing, they agreed to open up the hangar doors.

For ten months, we followed one orbiter every step of the way, as she was prepared for flight. And now I know how little I knew about what it takes to launch a shuttle.

Thirty years after it was first envisioned, it is still an icon to American technological prowess.

But beneath the surface, it is a vehicle riding on borrowed time.

GENE NURNBERG: The inventors don't make that stuff any more. The airlines don't fly that old junk anymore.

O'BRIEN: It was sold on the promise it would deliver cheap and easy access to space, but has never come close.

UNIDENTIFIED MALE: This is called a SNERT.

O'BRIEN: SNERT?

UNIDENTIFIED MALE: Means the Schedule Never Equals Real Time.

O'BRIEN: Remaining a finicky beast that demands attention like a spoiled child.

It is understood well by the people who make it fly, and yet, they live in fear of its secrets. Its hidden flaws.

COLEEN ADAMS, SHUTTLE PAYLOAD: I think in the back of everyone's mind, they are always thinking if something happens at the last minute, will we be able to recover? O'BRIEN: Twenty years ago, they predicted it would be in the Smithsonian by now, and yet, it flies on and on with no replacement in sight. And it is left to a handful of dedicated people to keep it going, knowing anything less than perfection means disaster.

QUESTION: What scares you the most about the job?

MIKE DECARLO, ORBITER TECHNICIAN: Screwing up.

O'BRIEN: This is their story. We begin where we normally leave off: at the end of a shuttle mission.

What goes up must come down. And in this case, we are talking down with a vengeance.

A shuttle's freefall from space is a slam dunk Newtonian moment. A blazing, precipitous, perilous, irrevocable dive toward terra firma.

UNIDENTIFIED MALE: I'm going to the Burn Card.

O'BRIEN: December 27, 1999. Welcome to the flight deck of the Space Shuttle Discovery, 15 years-old on her 27th voyage; 119 circumnavigations of the globe behind her.

Little more than an hour, after the crew nudged Discovery out of orbit over the Indian Ocean, they were knocking on the door at home on the shores of the Atlantic.

UNIDENTIFIED MALE: Do me one favor; let's not lose our concentration here and screw it up at the last minute; this is when everybody kind of gets silly.

O'BRIEN: The convoy crew started rolling even before Discover's long deceleration petered out, but the ground crew draws near with a healthy dose of caution.

UNIDENTIFIED MALE: You've got to go for your safety assessments.

O'BRIEN: An orbiter is brimming with a witch's brew of toxic hazardous chemicals and explosives.

UNIDENTIFIED MALE: We have the possibility of encountering poisonous gasses and vapors of hydrogen, ammonia, (UNINTELLIGIBLE).

O'BRIEN: Like a critical patient just wheeled into an emergency room, Discovery is quickly attached to life support. Umbilicals that purge hazardous gasses, and keeps the crew and equipment from overheating.

GREG KATNIK, NASA ENGINEER: I'm here as part of the orbiter landing recovery team, and specifically, my job is to get the big picture.

O'BRIEN: NASA engineer Greg Katnik spends much of his tarmac time scrutinizing the heat-deflecting and insulating tiles that cover much of the orbiter. Without them, the aluminum skin that lies beneath would be become soup during the 2300 degree reentry.

Katnik counts 153 dings, 24 of them an inch or larger. Overall, Discovery fared well during her 3 million mile journey, with one big exception: a tile is missing from the right wing on a flap called an elefan (ph).

KATNIK: Obviously, that's unusual. We will look into it, we will assess it, find out why that happened.

O'BRIEN: It's only one of Discovery's 24,000 tiles, and yet, it's void quickly becomes a focal point.

But that's more false bravado then technical reality. Astronaut Scott Kelly and everyone else here knows the loss of a single tile in a critical location means disaster.

UNIDENTIFIED MALE: We want to fly a perfect vehicle. We will find out why it happened, check it, and make a change if we need to.

O'BRIEN: A perfect vehicle. A million parts. 230 miles of wires. 1,060 plumbing valves and connections. All of it must be perfect.

Three miles down the road lies a gleaming, spotless climate- controlled hangar: Orbiter Processing Facility Number 1, the OPF.

The tailor made womb where the orbiter will be nurtured back to readiness for another flight. It's a glove fit; only an inch of leeway in any direction.

Discovery's long journey in space is over. Discovery's long journey back to space has begun.

O'BRIEN: Coming up: a mechanics nightmare.

UNIDENTIFIED MALE: The first time I had sweaty palms I was like, "We need to put this down. I have to put this down right now."

(END VIDEOTAPE)

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

NURNBERG: Depending on how it goes, I may try to catch the red eye Friday night.

O'BRIEN (voice-over): You've to get up at an ungodly hour when it's your job to hurdle humans to the heavens.

NURNBERG: I have to go to work. Why am I still sitting here?

UNIDENTIFIED FEMALE: I don't know.

O'BRIEN: It's just a bit after 4:00, and Gene Nurnberg is up and already restless to get at the job that has consumed him for 40 years. UNIDENTIFIED FEMALE: Have a good one.

O'BRIEN: Gene Nurnberg started out here readying Apollo spacecraft for moon shots. More than 20 years ago he got the first space shuttle, Columbia, ready for her first flight. Today he is still at it.

NURNBERG: I don't care that I haven't been promoted for 35 years. I already have the best job in the world, literally.

If you're here early enough, they haven't done this distribution yet. Here's the master log if you really want to find out what happened last night.

O'BRIEN: He manage what NASA calls "the flow."

NURNBERG: They call me dad just to tweak me. That feels kind of good. You have to keep it as tightly orchestrated as you can.

O'BRIEN: The 1.2 million-step minuet.

NURNBERG: Let me show you something.

O'BRIEN: Of maintenance, refurbishment...

NURNBERG: They get refurbished every flight.

O'BRIEN: Repair checks...

NURNBERG: We discovered some tarnished blankets.

O'BRIEN: Double-checks and still more checks...

NURNBERG: We have a criteria that says after eight flights, you change it.

O'BRIEN: ... that render a space shuttle ready for another ride.

NURNBERG: Let's go on up here.

O'BRIEN: Most days he begins with a solitary hangar tour -- a walk around, up, over and through the multi-tiered maze of scaffolding that envelops Discovery.

NURNBERG: It's not complicated rocket science, but you do need to kind of keep track of all of the things that are going on.

O'BRIEN (on camera): It's not rocket science, huh?

NURNBERG: No, it's just, you know, this thing and that thing and keeping it in order. That's not rocket science. What time is it?

O'BRIEN (voice-over): The wee-hours walk-around serves him well. As he retreats to the offices upstairs...

NURNBERG: We are late. We started this five minutes ago. O'BRIEN: ... where Discovery's day is choreographed, in a series of meetings that grow larger as the clock unwinds.

NURNBERG: Buddy was going to look at taking that off with buckets, but I don't -- when he looks, I don't think he wants to do it, anyway. So we will do the APU connect scape tomorrow?

Good job, though. That tape trick was nice work between you and the shop guys.

O'BRIEN: It might surprise you to know there are only a few NASA supervisors on this team. Most everyone in this room works for the space agency's prime shuttle contractor, the United Space Alliance, USA.

NURNBERG: What we're working on now is we have (UNINTELLIGIBLE) with three to four blankets.

O'BRIEN: It's a joint venture of aerospace giants Boeing and Lockheed Martin. Since 1996, NASA paid USA $1.1 billion a year to keep the shuttle fleet flying.

UNIDENTIFIED MALE: And we will not pull the pressure down with the radiators in the position that they're in. We'll wait until that issue is behind us.

O'BRIEN: But nothing comes easy or fast where the rubber meets the road, in the 30,000-square-foot climate-controlled orbital processing facility.

UNIDENTIFIED MALE: Have to go around that way.

O'BRIEN: From stem to stern, the good ship Discovery presents all kinds of obstacles for the hands-on workforce.

NURNBERG: I'm going to get you a good view. The best you can do in here.

O'BRIEN: Mike DeCarlo is on the team that works beneath Discovery's tail.

MIKE DECARLO, ORBITER TECHNICIAN: I'm going to be in the tightest spot in there just to get the bolts out of this thing.

O'BRIEN: Step into his office, the aft compartment, and you are instantly privy to the worldview of a mouse under the hood of a car.

DECARLO: It can stand on anything yellow. The struts -- like, these struts are OK. They're pretty strong.

O'BRIEN: This is clearly the business end of Discovery, where the three main engines are attached and a lot of other critical components live. Hence the plumbing and wiring spaghetti.

DECARLO: IT's a lot of monkeying around in here when you have to get something done in here. You can see the way we crawl back in here.

Here, I got it. Everybody get out and get in position.

O'BRIEN: The innocuous-looking piece of hardware they are removing is an auxiliary power unit, a crucial device that keeps Discovery's controls running during landing.

The price tag for a new unit, $3 million.

UNIDENTIFIED MALE: The first time I had sweaty palms, I'm like, "We need to put this down. I have to put this down right now."

UNIDENTIFIED MALE: That's what they call the pizza plate. This is the stand it'll sit on. Makes it easier to handle.

This is day five. You learn ways in and out. It wasn't meant to be worked on like we do. I don't think the engines were designed to come out as often as they do and a lot of other things. It's not mechanic-friendly.

O'BRIEN: At the other end of the orbiter, in the forward shop, spacecraft operator Lisa Davis would second that motion.

LISA DAVIS, SPACECRAFT OPERATOR: My first impression was that it was a lot smaller inside than I thought, you know, from what I had seen on TV, and pictures.

O'BRIEN: Here they do windows, the old-fashioned way.

UNIDENTIFIED MALE: We try to do it every 10, 15 minute segments.

O'BRIEN: The forward windows used by the commander and pilot get between 60 and 80 hours of elbow grease to remove the haze left by rocket plumes during launch. The goal: give the crew the clearest possible view of the runway at mission's end.

DAVIS: It's very labor intensive, but it does work.

O'BRIEN: You may wonder, as I did, if there isn't a more, well, space-age way to get the job done.

DAVIS: And the problem with using buffers is that there could be a situation where if a particle of debris were to get onto the glass, we might not have the feel of that, being underneath that buffing pan, and could possibly scratch a window.

We want to do things very safely. And sometimes the old way is the safest way.

UNIDENTIFIED MALE: Four, three, two, one.

O'BRIEN: Coming up...

UNIDENTIFIED MALE: Liftoff of the 25th space shuttle mission...

O'BRIEN: The day the old way was the worst way. UNIDENTIFIED MALE: Challenger, go with throttle up.

COLEEN ADAMS, SHUTTLE TECHNICIAN: That's the first thing that went through my mind, was, "My God, I hope it's nothing that we did on the pad."

UNIDENTIFIED MALE: I'm in at 15 seconds...

(END VIDEOTAPE)

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

O'BRIEN (voice-over): If you like rare birds, this is the place to be.

Ringed by fences, aggressively patrolled for trespassers, and beyond the reach of Florida's relentless developers, the 140,000 acre Kennedy Space Center is a safe-haven for all sorts of endangered species.

In fact, skimming through the maze of waterways that slice through the mangroves, it's easy to forget where you are. And then, in an instant, you are reminded.

Looming 525 feet above the water, the Vehicle Assembly Building, one the largest buildings on the planet, built during the space race to hold four of NASA's mighty moonships.

Today, it is the nexus of a small city of hangars, officers, labs and workshops, built to coddle the rarest birds of all: NASA's quartet of space shuttle orbiters.

UNIDENTIFIED FEMALE: I will say yes, and then verify that.

That's my final answer.

Coleen Adams knows what it's like to being a rarity.

ADAMS: Being a female is always difficult. When you are in a working environment, this is basically a male-dominated field.

O'BRIEN: After 17 years of hard work and hard knocks, in and around space shuttles...

ADAMS: You have got to be good at what you do and march forward.

O'BRIEN: ...she is one of Gene Nurnberg's chief lieutenants, and as such, is the highest ranking woman in the orbiter processing facility.

She is in charge of the so-called "mid-body," the shuttle's payload bay.

ADAMS: You don't want your glasses falling down into the orbiter.

O'BRIEN: This time around, her job is to pack Discovery's trunk with some new pieces for the budding space station.

She spends a good part of her day angling for resources, navigating a complex maze of competing chores.

ADAMS: This is the hardest part: pulling out all together and saying you are done.

O'BRIEN: Spend a little time with Coleen and you wonder how anything ever gets done in this world.

To get procedures changed so she could repair a part in the lab across the hall, she had to round up a dozen signatures.

QUESTION: That seems excessive.

ADAMS: I think it's more -- everybody wants to know what is happening with the equipment. If you weren't in a time constraint, it would be great. Because it is like a tool.

O'BRIEN: It's the most heavily used tool at all.

Whatever the action, every precisely prescribed step of way, there is a reaction of signatures and stamps on detailed checklists, first by the lead worker, then from a quality inspector from NASA contractor United Space Alliance, and then, if it's a critical piece of flight hardware, a NASA inspector also "buys the paper," as they say.

The running joke: a shuttle is considered ready for launch, once the stack of paperwork would stand just as high as the rocket.

ADAMS: We are working it until it goes away, and when it goes away, it will be a good thing.

RON DITTEMORE, SHUTTLE PROGRAM MANAGER: After Challenger, we put a lot of layers in the system to protect ourselves. And those layers were necessary because we found a lot of weaknesses in our process. And we probably overcompensated for it.

O'BRIEN: Slowly, but steadily, Discovery's secrets peel away, as technicians remove panels and pieces large and small.

Beneath the orbiter, the thermal-protection team is busy inspecting, tagging, patching, and replacing damaged tiles.

Technician Dennis Heathner (ph) sets up shop beneath the right- wing. He begins repairing the bare aluminum that was scorched after the missing tile came loose.

The paperwork is intense. In an eight-hour day, we will work six hours of paperwork to get two hours of work done.

O'BRIEN: While Dennis works, some shuttle gum shoes are all over the case of the missing tile.

UNIDENTIFIED MALE: We always have to worry about some kind of debris hit on the vehicle that actually impacted a tile and fractured it and caused it to fall off. That's what we're really worried about.

O'BRIEN: It is Greg Katnick's job to pour through the rehms of high speed, closeup movies, that captured Discovery's fiery trip to orbit in stunning detail.

KATNICK: Here's another interesting feature: we watched the body flap and you can see that there's a little bit of movement to it. You've got to treat everything on the vehicle like it's the most significant part of the vehicle. You never know when the smallest thing might end up being the most catastrophic. Who ever thought a simple little O-ring inside a booster would do what it did.

O'BRIEN: It was a leaky O-ring that sparked the Challenger explosion.

KATNICK: So, one little tile and one little location actually has far reaching consequences and causes to us do a very big investigation.

O'BRIEN: But the film did not capture a smoking tile, if you will; leading Katnick to surmise it probably fall off during Discovery's return from space.

KATNICK: As long as I don't see anything square with strait edges tumbling down, everything looks good.

O'BRIEN: Across the street, at the place where they make those tiles, engineer Mark Grey is doing an experiment to see how the tile was bonded to Discovery's skin. The missing article is the one of the larger, more complex tiles. A problem child.

MARK GREY: What concerns us is, if this one had been maybe four, five tile in front of it, and around the hydraulic lines, we might be talking about a whole another scenario today. You're talking about, basically, the astronaut crew not being able to make it back home.

O'BRIEN: Martin Wilson is the man in charge at the Thermal Protection System Facility. Here they mix, bake, mill, and coat about 1,000 tiles a year to keep the shuttle fleet flying.

The ceramic tiles are made mostly of silica, essentially highly refined sand.

They shed heat faster than a speeding shuttle. Safe to touch a few seconds after they come out of a 2,200-degree kiln.

High maintenance as they may be, they are probably the single greatest technological achievement of the shuttle program.

UNIDENTIFIED MALE: To be honest, you have to give credit to the people in the '60s and the '70s who actually invented this stuff, that really nobody to this point has come up with anything better. O'BRIEN: Amazing statement, when you consider the history of the space shuttle.

QUESTION: Was the shuttle way ahead of its time?

CHRIS KRAFT, FORMER NASA MANAGER: No. On the contrary, I think we used the technology we had in the '70s to build that machine, and we were conservative.

O'BRIEN: Because they had to be. Former NASA Flight Director Chris Kraft was there, still lording over the Apollo missions when the grandiose gold-plated ideas for what next, began circulating.

Many hoped for a three-pronged approach. Man missioned to Mars. Staged at a space station orbiting the earth. Built and serviced by a reusable spacecraft.

UNIDENTIFIED MALE: The United States can no longer afford the luxury of a throw away rocket. Our answer is the space shuttle, the world's first reusable spacecraft.

KRAFT: That wasn't in the cards, so the management of NASA decided what can we do? What will the budget allow?

O'BRIEN: It allowed for only one idea at a time. NASA had no choice. Without a vehicle to get humans off the planet, the rest of plan was academic.

So, NASA managers started making some big promises. They pitched at a machine that could operate like an airliner. A flight every two weeks. Cheap, easy, even profitable access to space.

KRAFT: I think it was overly aggressive, and I think we were overly optimistic about what the amount of things that were going to fly in space, but I think, you know, that's what it took to sell it.

O'BRIEN: It was road to ruin for NASA. The agency tried desperately to live up to its own hype, launching shuttles at a frenetic pace.

UNIDENTIFIED MALE: Liftoff! Liftoff! The shuttle has cleared the tower.

UNIDENTIFIED MALE: Engines throttling up. Three engines, and now at 104 percent.

UNIDENTIFIED MALE: Challenger, go with throttle up.

(APPLAUSE)

UNIDENTIFIED MALE: My controllers here looking very carefully at the situation. Obviously a major malfunction.

O'BRIEN: And then 73 seconds after the 25th shuttle launch, the Challenger exploded, shattering the myth of easy access to space. COLEEN ADAMS, SHUTTLE TECHNICIAN: That's the first thing that went through my mind, was, "My God, I hope it's nothing that we did on the pad."

O'BRIEN: The shuttle program would never be the same.

UNIDENTIFIED MALE: We have the report from the flight dynamic officer that the vehicle has exploded.

O'BRIEN: And neither would the people who were there.

NURNBERG: I have trouble going back to that, just because it was so traumatic and because you know some of those guy personally. I don't think about it as much as I probably should.

UNIDENTIFIED MALE: We're looking at -- checking with recovery forces to see what can be done at this point.

ADAMS: We all watched it. America watched it. Everybody saw it. And it's like, you go, hmm. You have to be careful. It's worth it.

O'BRIEN: When we come back: Pushing the shuttle to the limit.

UNIDENTIFIED MALE: You're going to run out of spares. You're going to run out of people that are building the hardware. And the hardware will become extremely expensive to build, because it's a one- time thing.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

O'BRIEN (voice-over): Astronauts may get all the glory, but they sure don't have the market cornered on risk in the space business. Mike DeCarlo is suiting up for the harsh environment on the ground, inside the space shuttle Discovery.

DECARLO: ... nothing gets past the glove.

O'BRIEN: He is donning, ever so methodically, a SCAPE suit -- a seemingly dyslexic acronym for self-contained atmospheric protective ensemble.

UNIDENTIFIED MALE: Well, the blue ones we call Gumby suits.

UNIDENTIFIED MALE: Want me to turn this way?

UNIDENTIFIED MALE: No leaks.

O'BRIEN: SCAPE is the mandatory dress codes whenever orbiter technicians work on parts of Discovery that contain hypergolic chemicals, meaning they instantly explode when mixed.

It's a clever, reliable way to fuel rocket thrusters in space, but a real nightmare to work with on the ground.

UNIDENTIFIED MALE: How do you do any work in the suit?

UNIDENTIFIED MALE: It's tough, but we can do it.

UNIDENTIFIED MALE: The bottom line is exposure can kill you. That's why we wear these suits.

O'BRIEN: During this SCAPE operation, the crew will install a new auxiliary power unit. That means working on some plumbing that might carry traces of hydrozene, a highly-toxic, corrosive hypergolic chemical.

UNIDENTIFIED MALE: Went a little too much.

O'BRIEN: If NASA had its way, this scene would not be happening at all. The agency would like the money to replace the old hydrozene power units with state-of-the-art batteries, no special attire required.

As a matter of fact, there is a long wish list of upgrades to some of the shuttle's most antiquated, high-maintenance systems, and there are plenty of them. The shelves at the supply depots are chockablock with 1970s technological time capsules.

And the testing equipment in this avionics lab would fit well in a computer museum. Here, engineers get their ticket punched on "trailing edge" technology. Over the years more than 3,000 suppliers have stopped making parts for the shuttle fleet.

UNIDENTIFIED MALE: Obviously it wasn't a good idea.

O'BRIEN: It's a big problem for shuttle program manager Ron Dittemore.

RON DITTEMORE, SHUTTLE PROGRAM MANAGER: Every day is another opportunity because something's awry. Something's amiss. A part broke, needs analysis.

O'BRIEN: NASA built its shuttle fleet to last 400 missions. Initially the agency expected to log those flights in 10 years. But two decades later, the orbiters still have more than 300 flights left in them. They're running a marathon with a sprinter's strategy.

DITTEMORE: Up to this point it's been kind of a very short-term approach; make the decisions you need to make to fly for five years. And that's very difficult to do. You only work on things that you can solve and implement in a five-year span.

O'BRIEN: But now, more than 20 years after the first shuttle launch, the concepts for a new vehicle remain just that. The problem- plagued X33, touted as a forerunner for a shuttle replacement, was killed this year before it ever got off the ground. It's now dawning on NASA the shuttle fleet will likely fly another 20 years, but that won't be easy or cheap. CHRIS KRAFT, FORMER NASA MANAGER: You're going to run out of spares. You're going to run out of people that are building the hardware. And the hardware will become extremely expensive to build, because it's a one-time thing.

O'BRIEN: From nose to nozzles, NASA has made some gradual improvements. The main engines have been redesigned three times. A fourth upgrade is in work.

In the cockpit, old gauges are being replaced by computer screens. The boosters are better, and the fuel tank lighter. The upgrade budget over the next five years, $1.6 billion. But NASA says it's not enough to keep the fleet flying safely for two more decades.

KRAFT: It's just like any other company. You have to have capital investment on get some gain.

O'BRIEN: And yet NASA veteran Chris Kraft says NASA's four orbiters could be flown more aggressively.

KRAFT: Same thing you do in a 747. When it lands it goes through an automatic check-out system to determine what systems are working and what systems aren't. And if something's not working, you replace it. And then you go fly it. You've got the best information on the performance of the system of the shuttle -- of the orbiter, when it lands. All you have to do is fill it up and go again.

DECARLO: It wasn't designed to be taken apart, that I know. I think there is places that we shouldn't go and shouldn't do anything with unless it's broke.

DITTEMORE: One day to do it, Miles, is just say I'm not going to look. I'm just not going to look, and I hope everything goes OK. I don't think that's a wise steward.

O'BRIEN (on camera): The stewards of the shuttle fleet are conservative because they have to be. Every time they launch, they assume the entire program is on the line. And it probably is. A program that, at one time, was judged on whether it could meet its own unrealistic launch schedule, now really only has one thing to prove: that it is not taking too many risks. And that, more than anything else, serves as a governor over what happens as the calendar and Discovery and her components move toward a launch date.

(voice-over): The solid rocket boosters are carefully inspected. The huge blimp-like external fuel tank is hoisted into place. The three main engines are removed and inspected in a gleaming engine shop.

UNIDENTIFIED MALE: Pull it up a little further, Joe.

O'BRIEN: The million-dollar toilet is gingerly hoisted into place; the landing gear cycled; and after months of painstaking preparation, a new tile is glued on to that wing flap. After combing through the old paperwork, engineers determined workers used the wrong sized liner when they attached the tiles six flights ago. This is good news, as there is no reason to suspect a problem that would ground the fleet. And suddenly it occurs to me, that pile of paperwork might be worth its weight.

Nearly nine month after she came them to roost, Discovery is ready to leave the orbiter processing facility. A milestone moment. Slightly bittersweet for the OPF crew.

ADAMS: When you start understanding how the whole thing operates, it's becomes a lot more than an orbiter or just a piece of equipment. It becomes something exciting. You are watching it launch and you receive it back and, you know, you get to go through this process, you can see where it got hurt on its journey, and you get to repair it, so it turns into, you know, a living entity.

O'BRIEN: Coming up, it takes a lot to make a shuttle fly, but not much at all to keep it on the ground.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

O'BRIEN (voice-over): Bolted on to the 6 million pound rock- crushing crawler, Discovery begins a three mile saunter to Launch Pad 39-A, for a departure point from earth.

A machine that travels six times faster than the speediest rifle bullet never exceeds the pace of a stroll on the beach on the ground.

Now that Discovery is standing on end, attached to her tank and boosters, exposed to the elements, the preparation puzzle reaches a new degree of difficulty.

Jim Pevarra (ph) is the man in the hot seat when the shuttle world pivots from horizontal to vertical.

With three weeks left before launch, they are wearily watching a hurricane in the Atlantic.

Should it dogleg toward the cape, Discovery would have to crawl for cover, creating a quandary for Pevarra.

UNIDENTIFIED MALE: What we're looking at is, integrating a schedule that's moving forward, preparing the vehicle for launch, and protecting a schedule that allows us to move it back off the launch pad. And, some of those activities are at odds with each other.

O'BRIEN: Pevarra (ph) is schooled in psychology and the law. Liberal arts, meet technical charts.

UNIDENTIFIED MALE: I'm basically looking at, you might have to factor in a little escape operation.

I'm not the boss, I'm conductor. The orchestra is paid much more than I am. I just point to the brass section and point to the strings. That's it.

Meanwhile, the team that orchestrates the countdown and makes the final decision to light Discovery's candles, sits down and plugs in to hone their skills.

It's a hair raising, simulated countdown in the firing room. It's more than just a drill. They must endure this "sim" to be certified for the real thing.

Next door, a small team of gremlins, led by engineer Mike Chanelli, is conjuring up all kinds of simulative mischief, several serious simultaneous failures for the launch team to contend with.

UNIDENTIFIED MALE: It's real; I feel it. It's a simulation, but when you are into it, it's real, and you realize you are practicing. Because one day, you might be doing that for real.

ED MANSO, NASA ENGINEER: If I can handle what happens today, you know, during the last nine minutes and during abort, I can be confident that, when it comes up to time for launch, and you have those type issues, I know exactly what I am going to go do. It is sort of like a textbook case. You have already seen, you've already been through the stress, and now, launch day is just another day.

O'BRIEN: Cue the flight crew and the crescendo begins.

The seven astronauts who will fly to the space station on Discovery drop in from Houston for some dress rehearsals.

Commander Brian Duffey and Pilot Pam Melroy practice steep dives to the shuttle runway in a gulf stream business jet, rigged to handle like an orbiter.

The entire crew goes to the pad to practice a scenario no one would like to see. A major failure on the ground that forces an emergency evacuation.

They practice releasing, though not riding, the slide wire baskets designed to whisk them off the 195-foot level in a hurry.

This is the crew's only speedy passage to safety. Space shuttles are not equipped with ejection seats or any kind of automatic crew escape system.

They get a quick tour of the blast crew bunker at the end of the line.

And some tips on driving their getaway tank.

NURNBERG: I think there's an overall awareness of what we are doing and the risk involved. We think about that. The people think about -- I mean it's not, there is no -- there is no escape system. There's no bail out.

O'BRIEN: As time draws near, the hurricane has now passed and the preparations at the pad do not break stride. A big piece of the space station, a trust that will support the station's solar panels is loaded into the payload bay.

Inside the crew module, the cupboards are carefully stocked.

And the entire stack is rigged with explosives. The self- destruct system that would be used as a last resort if Discovery veered violently off course, forcing ground controllers to blow up the rocket and all on board.

Near the end of this long, arduous, careful process, there remains a deep undercurrent of anxiety.

Discovery is layered with backup systems for her backup systems, but everyone here knows the score: NASA estimates 1660 scenarios where a single failure would cause the catastrophic loss of the vehicle and crew.

DITTEMORE: Because of Challenger, there is a certain mind-set that is very risk-adverse. In fact, a whole culture has grown up that wants to minimize the risk in everything you do, to the point where they would like it to be zero risk. Zero risk would paralyze you.

O'BRIEN: As it is, it doesn't take much to paralyze a shuttle.

Discovery's crew is suited and on the way. And her fuel tank is boiling over with super-cold liquid hydrogen and oxygen. So, the ice men cometh.

Craig Katnick's ice team is on the prowl for chunks of ice that might danger Discovery during launch.

But they are also looking for anything that doesn't look right.

In short, after months and months of painstaking work, it is the final inspection.

It's a three-inch pin lodged on a strut far from easy reach.

UNIDENTIFIED MALE: This is going to be significant.

UNIDENTIFIED MALE: You cannot assume that a little eight-ounce pin would get away Scot-free.

The damage to an engine or body flap could be severe, and because we did not want to take that risk, we decided to scrub.

O'BRIEN: 287 days after Discovery came home, she would wait at least one more day to fly away.

Day 288, an October 11, 2000.

UNIDENTIFIED MALE: Discovery looks ready to go.

O'BRIEN: Inside 20 minutes to launch, the phase known as terminal count, Gene Nurnberg and Jim Pevarra (ph) step outside to take it all in.

UNIDENTIFIED MALE: T-minus two minutes and 20 seconds and counting.

UNIDENTIFIED MALE: It's showtime. Get ready to rock 'n' roll guys.

UNIDENTIFIED MALE: Ten, nine, eight, seven, we have a go for a start, four, three, two, one. Booster ignition and liftoff of Discovery!

The biggest difference between then in the '60s, that first launch, and now, is somehow, I don't cry anymore.

UNIDENTIFIED MALE: These are people that, as a matter of course, every couple of months, put everything on the line and there is a lot on the line.

ADAMS: I always wait that 60 seconds after the launch. You can see the boosters falling and the crowd quiet. It's very emotional.

UNIDENTIFIED MALE: You watch those first two minutes and you watch that contrail go up into the sky, lit by the sun, and you see the main engines going off into the distance. That's the poetry of the process.

UNIDENTIFIED MALE: Welcome into space and congratulations.

UNIDENTIFIED FEMALE: Thanks Tom; it was beautiful.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

HARRIS: The space shuttle may be saddled with antiquated components, but taken as a whole, it remains state of the art.

Twenty years after it first flew, it is the only reusable space vehicle in the world. And still no replacement in sight.

I'm Leon Harris. That's this edition of CNN PRESENTS. Thanks for joining us.

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com