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American Morning

Return of Shuttle; Interview With John Glenn

Aired August 09, 2005 - 07:30   ET

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

MILES O'BRIEN, CNN ANCHOR: So there's the shuttle. There's the Earth spinning beneath it.
The Earth moves essentially about a thousand miles each orbit. So, as time goes on, different ground locations become available. Kennedy Space Center, there were two opportunities this morning. Suddenly, White Sands, New Mexico, became available. And now this first opportunity at Edwards Air Force Base became available, and that's what we're seeing now, because the decision has been made, the rockets have been fired, and Discovery is on her way home.

So, let's take a look at what the crew would see as it came -- as they came across the Pacific here. Entry interface, that kind of first feeling of the effects of the atmosphere over the Cook Islands in the South Pacific into Southern California, right over Los Angeles.

In about a half-hour time, if you live in Southern California, Los Angeles, go outside, take a look. There's a good chance that you're going to be able to see the space shuttle as it streaks over. It will be dark where you are, but it will probably be lit up by the sun. The landing on the runway, runway 22, will curve just like that after a big right turn.

Let's take a look at a pilot's eye view of what Commander Eileen Collins and the crew will see as they come on down and do that landing to the southwest. Down they come over the mountains and into the high desert, where the weather is almost always good. Straight down on that three-mile-long runway, keeping the speeds and everything just right, because this is, after all, a glider. One-shot deal re-entry and landing.

We're going to talk about re-entry with a couple of people who have been there and what's going on right now in the space shuttle. Right beside me is Cady Cull -- excuse me -- Cady Coleman, who is a -- done this twice on space shuttles. And also with us from Columbia -- Columbus, I should say -- I'll get through this -- is Kathy Sullivan, a veteran space shuttle astronaut.

Good to have you both with us.

Kathy, we're post de-orbit burn, just beginning the first feeling of getting into the atmosphere. What's going on, on board that space shuttle right now?

KATHY SULLIVAN, MISSION SPECIALIST: It's a pretty quiet orderly time. Everybody is strapped in, waiting for the first contact with the atmosphere and the milestones that's called entry interface, which really marks a bunch of computer mode changes as the spacecraft begins to shift its mind from acting like a satellite back into acting like an airplane.

And the crew right now, as least what I was always doing with my crews, are lightly chatting a little bit and just really becoming vaguely aware of the start of a sense of deceleration. You actually feel very subtle first perceptions of deceleration since you haven't felt any external forces on your body for 12 days.

M. O'BRIEN: All right. That's going to occur in about 10 minutes' time, 7:40. There you see that plasma glow around the space shuttle that will occur right around that time.

Let's talk about that. When do you start feeling, Cady Coleman, when do you start feeling the effects of gravity? Is it right around that time, that sense of deceleration?

CADY COLEMAN, FORMER ASTRONAUT: It's just after EI. And I think before you start feeling it on yourself, you start to see things that you forgot to put away around the space shuttle that have been kind of floating or maybe lightly tacked up with Velcro, start to actually fall to the floor. Hopefully, there's not too many of those. We try to do a pretty good cabin clean-up.

But as you start to see that plasma outside after EI, that's when you just start to feel just heavier and heavier, and suddenly you're sitting in a suit, and the suit is sitting on you.

M. O'BRIEN: The suit is sitting on you. And I assume at that point, Kathy, that gravity feels much more strong than it does, to those of us who are used to it every day. You've had a couple of weeks away from it.

SULLIVAN: Yes, you are very aware of that. Actually, the first sensation I remember was feeling being aware of my eyeballs. My seat's being held back by the orbiter, and my suit's being held back by the seat belts, and all of the soft parts of my body were still trying to go fast. I literally felt I could feel my eyeballs.

The same as Cady said, also you're looking for things like your pencils to begin falling or the laundry bag hanging and floating at the end of its tether and sink down.

Once you finally get down into the Earth's atmosphere and really begin to slow down enough that you're flying truly like an airplane, they'll pull about a G-and-a-half, 1.4 times the effect of gravity as they turn onto that alignment, and it feels a whole lot more than 1.4 Gs after 12 days.

M. O'BRIEN: I suspect so. Did you have the same experience, Cady?

COLEMAN: Oh, absolutely. It just begins to be a little heavier and heavier, and especially if you're, I think, probably Andy Thomas on the flight deck, he's probably got a camcorder to record some of the video inside and what it looks like to be inside the fireball, so to speak. And that camcorder will get heavier and heavier and heavier, and I'm sure he's got it on a tether so it doesn't fall.

M. O'BRIEN: Let's take a look at the feed that's coming out of NASA right now. This comes from Mission Control. And this gives you sort of a real-time representation of where the shuttle is. No live cameras on there right now. But you can see the nose is very high, which indicates what we just showed you, that they're beginning that period of that breaking effect, very nose high, and those sort of s- turns, if you will, as they sort of begin that process of re-entering the Earth's atmosphere.

Kathy, at that point, with the nose that high, you really don't have a sensation of being -- pointing up, because you're still in, relatively speaking, zero G or weightlessness.

SULLIVAN: That's exactly right. This is the interesting moment when you do know you're going home, you did do the burn, yet you are still in zero gravity. So, you're still really just a ballistic object falling down towards the top of the atmosphere. And that high nose up and wings-level attitude is very precisely calculated, one, to be sure you get the stable initial contact with the atmosphere at entry interface, and then you'll have the shuttle roll over onto its pre-bank maneuvers to make sure you bite down into the atmosphere. And you can begin doing the ranging, s-turns, that are familiar to basically anyone who has ever flown a glider knows you come in with more energy than you need to actually get to the runway. And you bleed it off with turns rather than coming in too short.

M. O'BRIEN: Now, the peak heating will begin at about -- excuse me. That will begin at about 7:46. So that's coming up in just about 10 minutes. And when we say peak heating, especially in the wake of Columbia, Cady -- we're going to be watching that very closely -- that was when things started going wrong, of course, for Columbia. In this case, we have a big difference. This vehicle is coming in like no other. We know more about this vehicle than any spacecraft that has returned from space.

COLEMAN: Absolutely, Miles. And during the flight they spent a lot of time doing inspections. They actually took the shuttle robotic arm, picked up an extra boom, and then used cameras on that boom to examine every bit of the underside of the shuttle, the leading edges, you know, things that we weren't able to do with Columbia, the lesson that we learned. We need to understand what is the state of our vehicle? Especially on a test flight like this. We have looked at the vehicle. The vehicle looks good. I think we're ready for entry.

M. O'BRIEN: All right. Discovery right now at 100 miles in altitude, just a few minutes away from that entry interface moment, and that's about a 75-mile altitude.

Kathy, how concerned should we be through all of this period of peak heating, given all that has transpired with Columbia, and then the problems we saw on this mission?

SULLIVAN: The problems we saw on this mission, Miles, I think, were quite minor in actual practice. And we had, as Cady just said, scads of data that were poured over carefully by a large team of folks on the ground. So, in that sense, we can be more confident than probably we had the true ability to be on any preceding shuttle flight.

Knowing more about the physical condition of the bottom of Discovery is one thing and a very worthwhile thing. The physics of coming into the Earth's atmosphere from mach 25 are still the physics of coming into the Earth's atmosphere from mach 25. And from now until touchdown involves removing from Discovery the same amount of energy, basically, that was injected into Discovery on liftoff. It's a huge amount of energy. It always poses a huge hazard.

M. O'BRIEN: You know, it's interesting. Up until the loss of Columbia, many people had the wrong impression, clearly, who watched shuttle flights that the launch was the big concern. And after the first eight-and-a-half minutes, you were home free. Obviously not so.

The destination this morning is Edwards Air Force Base, not here. Weather being the issue.

CNN's Ted Rowlands is there to give us a sense of the scene there. Obviously a little bit of a scramble although the whole notion of going to Edwards was certainly a possibility, wasn't it, Ted?

TED ROWLANDS, CNN CORRESPONDENT: Yes, indeed. But I'll tell you, the energy level skyrocketed when the final decision was made that indeed the shuttle was going to come here. It's a skeleton crew that NASA has here, enough to handle it, of course, but not nearly the amount of people that are at Kennedy.

And clearly, all of the family members of the astronauts were waiting, or were going to be waiting at Kennedy, and that reuniting will have to be done in Houston, which should happen later today.

That said, they are clearly ready to do this. This will be the 50th time that a shuttle has ended a mission here at Edwards. And as it approaches, the anticipation is up. They have cleared the runway, and they have made, as we mentioned earlier, several flyovers to make sure that the weather and everything is fine. And it is a beautiful morning here for a landing.

And folks in Southern California, if they are up, should look out their windows and walk out to their driveways and look up to see if they can get a glimpse of the shuttle as it screams across the Pacific Coast. About the -- it will above Ventura and Oxnard as it makes its way to the Mojave Desert here to Edwards.

M. O'BRIEN: Ted, Discovery right now is 5,300 miles away, but will be there lickety (ph) split. Just about a minute to entry interface, an altitude of about 80 miles.

The thing -- I mean, let's face it. A shuttle kind of flies like -- John Young, the first commander, told me, he said it's like flying a piano. It really doesn't have great aerodynamics. But down it will come.

And we should tell folks it really will be worth it, because even though it's dark on the ground, when Discovery goes over Los Angeles, the altitude will be about 100,000 feet, putting it well above the limb, so-called, which means it will be in sunlight. So while you won't see streaking plasma at that point, it will be a lot slower, you will get that view. I hope folks in California have had a sense of that.

Ted, you've got a great front row seat there. Of course, it will be dark for landing there. And this is the first night landing at Edwards, I believe, since '91. Is that right?

ROWLANDS: Correct. It's the first landing since 2002, with the landing of Endeavor, but the first night landing since '91. And we may not be able to see much from our vantage point, because it will be so quick. But we will be able to hear the boom, and that is expected to take place at about eight minutes after the hour. And then the touchdown is expected for 12 minutes after the hour, which we are eagerly anticipating.

We are hoping to hear from the astronauts in some form at some point. We have not been guaranteed that though. It will be up to the astronauts and their fatigue level, whether they want to address the media or not. A press conference has been tentatively set for about six hours after the shuttle lands.

M. O'BRIEN: Well, I guess they would be excused if they decided they couldn't be up to it, but I suspect we'll see them. Ted Rowlands, right now as Discovery is 72 miles in altitude, traveling all of 17,000 miles an hour.

And in the time Ted Rowlands was talking, just that last little bit there, it picked up about 500 miles, now about 4,900 miles away from Edwards Air Force Base, where the weather is CAVU. That's ceiling and visibility unobstructed. That's a pilot term. Chad Myers knows that one. And Chad Myers walked us through a rough morning here at the Cape as well.

Hello -- Chad.

CHAD MYERS, CNN METEOROLOGIST: Yes, Miles, did it turn out to be that bad now that the sun's up and you can see around?

M. O'BRIEN: It's gorgeous here, as you would expect.

MYERS: Yes.

M. O'BRIEN: Unfortunately, they couldn't land at this hour. I think I showed new that animation.

MYERS: Right.

M. O'BRIEN: There's only certain times when they can hit Florida.

MYERS: Great. Exactly. Because now they're too far to the west. There's no way they could turn that thing far enough to get it back into Florida at this point. But they have perfect weather. The visibility at Edwards right now 30 miles. The temperature is 72. The entire area here around Edwards Air Force Base is in really good shape at 72 with a relative humidity of 50 percent, it doesn't get a whole lot better than that.

There are some clouds from about Long Beach southward, but Edwards Air Force Base, in fact, is right in the desert.

As we move you along to 7:45 and 8:00, not a cloud in the sky from Edwards all the way down even into L.A.

And we were looking at all of the clouds and thunderstorms in the sky around Kennedy this morning. The main problem was thunder and lightning that was offshore and a few scattered showers on shore. But obviously now most of Florida will have a picture perfect afternoon.

Miles, hey, I have a question for you that I'd like for you to ask one of the astronauts. Does it get warm in the shuttle when they're doing that plasma burn? Can they actually feel the heat inside?

M. O'BRIEN: I have just the right guy to pose that question to, Chad Myers. He's waiting in the wings here. We are privileged to be joined by former astronaut, former senator and current icon John Glenn.

Senator, good to have you with us.

JOHN GLENN, FORMER ASTRONAUT: Thank you, Miles. It's good to be with you.

M. O'BRIEN: And, you know, I think back -- of course, we'll talk about your shuttle run in just a moment and whether it gets -- well, let's talk about that first of all. Does it get warm on the flight deck or the mid-deck of the shuttle as it is coming back to Earth?

GLENN: I was in the mid-deck, no, it didn't -- the temperature is pretty well controlled by those controlling. Of course, you're in your suit also, so you've got ventilation there. So I didn't notice any heat at all.

M. O'BRIEN: That's good to know. All right. Let me ask you this. Back on your first flight...

GLENN: Yes.

M. O'BRIEN: ... that was a re-entry to remember. And there was all kinds of concerns, because there were some issues with your retropack. And everybody held their breath on your re-entry. No one was sure if your heat shield was intact as it should be.

GLENN: Yes.

M. O'BRIEN: Did you get hot on that one?

GLENN: It took a while for the heat to soak in on that one, but by the time I was down on the main parachute it was getting very uncomfortably warm inside. And when I was on the ocean bobbing around, it was getting real warm inside. And so it took a while for the heat to soak in. There's pretty good insulation on that, titanium tiles on the outside. And you had pretty good protection. But heat soaked into that one more than it did on the shuttle.

M. O'BRIEN: Boy, I bet when you felt that heat you were thinking, oh, boy. That's some serious business, isn't it?

GLENN: Well, when you're coming through re-entry in the high heat of re-entry, I could look out the window, the little window right over my head like this and see the chunks of retropack or -- yes, retropack and the ablation shield material coming back by the window in sort of a gold burning color. And so that was very impressive, to say the least.

I think that was a unique re-entry, because of all of the chunks of the retropack breaking off. We left that on to make sure the heat shield was held in place. There had been two signals that went down to the ground that the heat shield was loose in orbit. And that's the reason we did it that way coming back in.

M. O'BRIEN: That was something. Let's go back to Mission Control. I just want to show you some pictures here and give you a sense of where Discovery is right now. It's about 4,000 miles away from Edwards Air Force Base, headed over the South Pacific.

As a matter of fact, if you could lose that banner, you could see a little bit better where Discovery is in the world. You can see that nose high attitude up here, of course, but down here, of course, is Discovery. And entry interface, peak heating, all of the key moments now, big plasma trail coming behind it over the Cook Islands.

Cady Coleman, what will they see there if they have an opportunity there in the Cook Islands? I guess it would be nighttime for them. But what will they be able to see?

COLEMAN: At this point, the shuttle is low enough that it's not just some tiny little satellite going by, like a little speck, a little star. This is like four airplane contrails all melded together, bronze, gold. I hope somebody's out there watching, because it is amazing to see. It's a runner-up to a launch. And you can actually see the kind of ghost of the shuttle at the very front of that.

M. O'BRIEN: Peak heating under way.

Kathy Sullivan, do you recall what you were thinking at this time on your re-entries? You were talking about sort of a little bit of chitchat, an exchange between the crew. When does it get tense, if at all?

SULLIVAN: You know, as one of my former colleagues said, the time of greatest focus in something like this is kind of the moment from when it starts to the moment to when it's over. So it's focus the whole way through. It's almost impossible to not comment on what's streaking by the windows outside. It is very impressive. But the primary attention for everybody on the flight deck is just focused on the controls, the instruments, and watching for any early indications that you might spot if something is diverging and not behaving as you expected.

You know, Miles, the senator talked about the heat soaking into his Gemini capsule. It's just worth a little bit of a note. The same thing happens with a similar amount of heating on the shuttle, but the tiles make it such that the hottest temperature inside a shuttle cabin isn't reached until about 45 minutes after touchdown.

M. O'BRIEN: Isn't that interesting? It actually reaches peak heating in the aluminum skin on the ground there at Edwards Air Force Base.

Of course, senator, anyone who has seen a Mercury capsule and has seen how small it is and how close you were to the heat shield can really fully understand that. I'm curious now. Tell us a little bit about your shuttle mission and what you recall about re-entry there. I'm sure there's a great sense of, you know, euphoria that goes along with having completed a successful mission.

GLENN: Well, there is, but I think everyone is always glad to get through re-entry, too. And, of course, on the shuttle mission I was on, I was down on the mid-deck. So I didn't have a chance to see much of the streaming by the window or anything like that, because it's like you're riding in a little room down there, and you don't see much.

But it's a time period. It's low deceleration down there. In the earlier flights, we were up to around 8 Gs on re-entry. That's being taken straight into your chest. So it's not as bad as people think sometimes.

And on the max you get up to in the shuttle is just a little over about 2 or just a hair over 2 coming back in and about 3 on launch, because, after all, the thing is built with a lot of scientific equipment. But that means you have a longer re-entry time coming back in also.

M. O'BRIEN: Well, and that, I guess, adds to the tension, I suppose, somewhat, doesn't it?

GLENN: I suppose so. Although, you know, the people are just -- you've practiced all of this and gone through it enough times, the crew has gone through it, particularly the crew that's actually controlling it now, the commander and the pilot. They've been through this, you know, so many times on simulations that I won't say it becomes second nature. Nothing in the space flight ever, I think, becomes second nature. But they've done it so many times, and you have a lot of confidence that everything is going to work out OK.

M. O'BRIEN: Well, that's what you want. Columbia is now 16,100 miles an hour in the midst of making those bankings. It's in a left turn right now. Those turns -- once again, let's remind people what that's about, Cady Coleman. That is just to bleed off energy. As the senator pointed out, you want the crew to experience not too many Gs, not too much force. And so that's what this is all about. It might give you the false impression that it's kind of a docile event, but it isn't.

COLEMAN: Well, we're actually feeling a lot of Gs way up high like this. We are doing banks to burn off some energy, and at the same time always keeping the belly of the orbiter into the wind, so to speak. We're just beginning to use our control surfaces. There's enough air to actually use the flaps and the elevons (ph) on the rear end of the shuttle to control. It's becoming more of an airplane than a spaceship.

And it's when we actually get down closer to the runway on that heading alignment cone, as you make that turn, that's where those Gs are going to build up.

Right now, as we look out the window and we see this plasma display, the chemist in me, you know, is amazed to actually see what I've looked at in equations to see it in action. And, you know, really now there's enough air molecules that we're running into them. We're busting them apart. And when they recombine, when the electrons really go back into the atoms, that's when we make that plasma. And it's pretty neat to be inside it.

M. O'BRIEN: So you can appreciate it on a couple of levels. Do you really recall actually thinking like a chemist when all of this was happening before you?

COLEMAN: It was just so beautiful looking out the window. And it was -- and also, actually, struggling to make sure you captured some of it with the camera. And that makes you have to kind of take yourself outside. And at the same time, like Kathy said, you know, it is business. You know, we have practiced this entry. We've all got a job to do. And everybody is doing that job and focusing on that and trying not to take too much of your brain away to enjoy the sights.

M. O'BRIEN: Discovery is now 15,400 miles an hour, an altitude of 230,000 feet. And these are critical moments, if you hearken back to two-and-a-half years ago, moments when we first got indications that Columbia was in trouble. These are peak heating moments. And, of course, at that time, no one knew on the ground, no one knew that the heat shield had been lethally breached by foam, just about a minute or so after launch.

Let's go back to Kathy Sullivan and talk about that experience right now. Everybody talks about the spectacular colors and the real light show that occurs outside the window. Do you remember that? Is that distinct in your mind, that multi-colored effect?

SULLIVAN: Oh, it is unforgettable. And anyone who has seen it will never, ever forget it. It's an incandescent bright orangish white. It's streaking past you, and you can't quite comprehend what the texture seems to be that's streaking past you.

The other thing is you're coming down sort of blunt-belly forward, as Cady mentioned. And so you're plowing a big hole in the atmosphere. You have a wake where all of the air sort of reattaches and recombines above the orbiter. And that is a very turbulent recombination process.

So there's this ball of light, it seems like, perched above the overhead windows that pulses and flashes into the cabin episodically. It's not very regular. It is like the world's biggest flashbulb bank went off or strobe light went off right over your shoulder. It's just an astonishing, absolutely astonishing thing to see.

M. O'BRIEN: Wow! That's a great description. That's one of the best descriptions I've ever heard, Kathy. Thank you for sharing that with us.

Fourteen thousand 500 miles an hour. As we said, this is a critical moment. Already Discovery is doing better than two-and-a- half years ago, 223,000 feet in altitude right now.

The person sitting in Mission Control who made the decision earlier today and who will preside over the re-entry is Leroy Cain, a flight director who specializes in launch and re-entry. He is back there in that same job that he performed two-and-a-half years ago, having to go through the demise of Columbia and her crew. Obviously, a tremendous emotional experience for he and his team. A job, though, done very professionally.

We talked to him about what it was like for him that day.

(BEGIN VIDEOTAPE)

LEROY CAIN, SHUTTLE ENTRY FLIGHT DIR.: When we came in that morning, it was like any other entry that I've been associated with, even as flight director or as flight controller.

UNIDENTIFIED MALE: Houston, we'll get to 304 in five minutes.

CAIN: There came a point in time after entry interface where we had some indications.

UNIDENTIFIED MALE: Stand by. I've just lost four separate temperature transducers on the left side of the vehicle.

CAIN: We started to think about it and talk about it.

UNIDENTIFIED MALE: And there is no commonality.

UNIDENTIFIED MALE: No commonality.

CAIN: I began to think about the left wing and about the possibility that we had ingested hot gas.

UNIDENTIFIED FEMALE: And we're taking a few hits here. We're right up on top of the tail. Not too bad.

M. O'BRIEN: It must have been like a kick in the gut, though. It had to be a moment of dread. CAIN: Yes, it was. It certainly was. I mean, it came to a point during the entry when we were not able to -- after having lost communications with the crew and we weren't able to recover it through our normal techniques.

UNIDENTIFIED MALE: We do not have any valid data at this time.

CAIN: We didn't have tracking. There's all of these things are pointing to the fact that we've lost the vehicle.

UNIDENTIFIED MALE: Columbia, Houston com-check (ph).

CAIN: It became clear to me that the thoughts that I had, the fears as they were at that point that I had, were -- had been true.

UNIDENTIFIED MALE: The FCOH contingency plan procedure.

CAIN: And then after that point, we actually saw some video. I had access to some video in the control center that we wouldn't normally have. But that just confirmed what I already knew.

M. O'BRIEN: What was that like seeing that? That just kicked me in the gut.

CAIN: That was hard to look at, because we were -- we needed to go continue to do our jobs at that point. And so I, you know, looked at it saw it. It confirmed what I had heard. And fortunately, I was able to treat it as data at the time. It was data that we needed, frankly, to confirm what I had heard and be able to move on from there.

UNIDENTIFIED MALE: Have not acquired anything. We are only acquiring false locks at this time.

UNIDENTIFIED MALE: I copy.

M. O'BRIEN: Do you feel at all guilty about what happened?

CAIN: I don't think I would call it guilt. I would not call it guilt. I think that we've all learned from this experience. None of us wanted to personally fail the crew. These were friends and neighbors of ours, you know. Their kids go to school with our kids, that kind of thing.

I am personally at peace with where we are today and with moving forward. If I wasn't, Miles, I wouldn't be able to do this job. I would not be able to do this job. I got myself to a point, through a natural process of being able to say, let's go, let's move forward.

(END VIDEOTAPE)

M. O'BRIEN: Discovery is now traveling 11,500 miles an hour. It's 1,000 miles from Edwards Air Force Base and has gotten further than Columbia. So what we can say is today will not be like two-and- a-half years ago. Of course, we had a strong sense of that on this mission despite those concerns about falling foam, despite all of the worries we had about protruding gap fillers. The fact is we knew more about this spacecraft than any spacecraft that ever returned to Earth.

John Glenn, can you imagine if back in 1963 you had the imaging capability that we had today, they would have known precisely how your heat shield was?

GLENN: Well, they would have, and we had been able to look at it and see that everything was OK out there and see that it was not loose. But, you know, this whole thing has progressed so rapidly here, and there's so much better coverage of things now. But back in those days, you know, on that first flight, the first orbital flight, they didn't even want me to take a camera along, period. And how far we've come since that time. I did finally take one along, a little Minolta automatic, the first of the automatic cameras. But that was only decided about a month before the flight. So we've come a long way in this idea of photo coverage, and it's better now.

M. O'BRIEN: A long way from that Minolta. We are past peak heating. We are 14 minutes away from touchdown. Right now 800 miles away from Edwards Air Force Base, 10,000 miles an hour. And that's getting slow for a space shuttle, relatively speaking.

Cady, I don't know about you, but I'm breathing a sigh of relief. How about you?

COLEMAN: Oh, definitely. I think all of us have been waiting for this day, knowing that we were ready. And yet, when you really get past that point, it feels pretty good.

M. O'BRIEN: Kathy, how about you? Were you holding your breath a little bit there?

SULLIVAN: You know, Miles, I'm going to hold my breath until its wheels stop on the center line. I'm glad they're through peak heating with no adverse signs, but nothing beats wheel stop.

M. O'BRIEN: Wheel stop, it is. Really, when you think about it, this mission was about re-supplying the space station, but it was also really about getting back in flight. Wheel stop is a goal, isn't it?

COLEMAN: It's true. But, you know, everything from the time you start training until the time you land back on the ground, there's risk involved, Miles. It's a dangerous business, but it's an important one. It's something humans have to pursue, and sometimes it's just hard to watch.

M. O'BRIEN: Kathy, would you echo that comment?

SULLIVAN: You know, I would indeed. I found myself in a bit of a debate on the robots versus humans point just the other night. And, you know, I remarked to the person questioning me, you're right. You probably can send cameras to Mars cheaper than you can send people. You could also send a camera to the Olympics cheaper than you could send an athlete. And you could do robots there, too.

It's not the same. This is about human experience, and it's about immersing yourself so much in something that is so challenging and transformative that you become transformed. And because other people are involved, many people across nationalities and ethnic lines and everything else feel that sense of joining in. We don't do that with machines. We do that with each other.

M. O'BRIEN: That's a great point, because that debate continues. And right now Discovery is continuing those banking maneuvers, about 470 miles away now from Edwards Air Force Base. Imagine how far it has traveled in just a short period of time that we have been talking here.

Let's listen to Mission Control for a minute.

UNIDENTIFIED MALE: Your touchdown is 2,600 at 205.

UNIDENTIFIED MALE: And Discovery copies. Thank you.

UNIDENTIFIED MALE: That call confirming that Discovery is right on course for its touchdown on runway 22 at Edwards. Discovery within range of ground tracking radar now from the landing site. Discovery speed now nine times the speed of sound, Mach nine, about 6,100 miles per hour.

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