For Astronauts, Waiting Is the Hardest Part
STEVE INSKEEP, host:
This is MORNING EDITION from NPR News. I'm Steve Inskeep.
The shuttle Discovery is headed for California this morning. Earlier today, storms at the Kennedy Space Center in Florida forced NASA to scrub two landing possibilities there. And now the shuttle will try to land at Edwards Air Force Base in the Mojave Desert. The first landing window comes in about two hours. Joining us now to discuss the shuttle's return is Carl Walz. He's a veteran astronaut who spent six months aboard the International Space Station. He is now associate director for Life Support and Habitation at NASA headquarters in Washington, DC.
Good morning to you again.
Mr. CARL WALZ (Associate Director for Life Support and Habitation, NASA): Good morning.
INSKEEP: OK, you've been on the shuttle four times, four different flights, and one of them actually was diverted to California after several days of delay. What was that like?
Mr. WALZ: Well, initially, we were disappointed because we wanted to land in Florida. Our families were there. And this was after our long-duration flight, so we were really fired up to see our families. But after the three days of delays, we were just happy to get back to Earth, whether it was in Florida or in California.
INSKEEP: And Edwards Air Force Base is the alternative--well, I mean, it never rains in California, as they say. I mean, it's just because the weather is usually good there, pretty much.
Mr. WALZ: Yeah, pretty much, the weather is always good, and also there's lots of runways. There's the big hard-surface, concrete runway 22 that they'll use today, plus lots of runways on the lake beds.
INSKEEP: That used to be the preferred landing site for the shuttle.
Mr. WALZ: That's right. Right, and when I was at test pilot school, I used to see the shuttle land there quite frequently in the early days.
INSKEEP: And why did they change it to Florida?
Mr. WALZ: Well, by going to Florida, they can reduce the turnaround time for the shuttles. When you land in California, that introduces a week to two-week schedule delay because you have to then transport the shuttle from California to Kennedy.
INSKEEP: So NASA now accepts that delay in an effort to get the shuttle down on time here. Now let's talk a little bit about what the astronauts will experience a couple of hours from now if this landing window is met, if they go ahead. What does it feel like as you first start to hit the atmosphere again?
Mr. WALZ: Well, there's two things. The first is the visual effect. If you're on the flight deck, you start to see the hot gases, the plasma, and it glows and starts as a pink glow around the vehicle. And so you're driving along in this fireball. And then as you get lower in the atmosphere, that pink goes to just a white--looks like fog if you're driving at night with your bright headlights on. And also, if you're on the flight deck and you can look out the upper windows, you can actually see these tubes of plasma shooting up over your head. It's really spectacular.
INSKEEP: When you say plasma, you mean this is air. It's atmosphere.
Mr. WALZ: This is super heated gas. It's the top of the atmosphere that gets super heated as the shuttle slams into the Earth's atmosphere.
INSKEEP: Now the most dangerous moment in this entire sequence is what? Where do you worry, if you worry at all?
Mr. WALZ: Well, I think there are several areas, but when you're going through that area of peak heating, which is around Mach 21...
INSKEEP: Twenty-one times the speed of sound?
Mr. WALZ: Twenty-one times the speed of sound. That's where you're getting that peak heating when you're meeting the atmosphere. So that's one place where you really want your thermal protection system to be as good as it can be.
INSKEEP: OK. And what does it feel like?
Mr. WALZ: Well, as you get lower into the atmosphere, gravity starts to return. And so things that had been weightless, like your checklists, for example, all of a sudden start to bend and your arms and your legs start to feel heavy, even though you're seated in your suit--or in your seat, your arms start to get heavy and then you start to realize that, `Uh-oh, gravity's coming up.'
INSKEEP: Do you have time in that sequence to think about what an astonishing thing it is you've just done and that you're doing?
Mr. WALZ: I think that the folks on the mid-deck have that chance to reflect. The folks on the flight deck are very concentrated on their checklists and, of course, their responsibilities for landing.
INSKEEP: Because you don't want to screw anything up at that point.
Mr. WALZ: Absolutely.
INSKEEP: OK. Well, Carl, thanks very much. Appreciate your help, as always.
Mr. WALZ: Oh, you're quite welcome.
INSKEEP: Carl Walz is a shuttle astronaut, a veteran astronaut. He still works for NASA and he's joining us this morning as we wait for the return of the shuttle Discovery. We are expecting it to attempt to return to Earth at Edwards Air Force Base in California, and the next window, the next opportunity, comes in about two hours.