RENEE MONTAGNE, host:
The space shuttle Discovery is scheduled to land this morning just after 9:00 a.m. Eastern Time, weather permitting. NASA says the shuttle's heat shields are in excellent shape. But aside from launch, landing is the highest risk part of any mission. NPR's David Kestenbaum is at the Kennedy Space Center in Florida and joins us now. Good morning.
DAVID KESTENBAUM reporting:
MONTAGNE: So, David, one detail we can say. The shuttle has to slow from 16,000 miles an hour to a full stop. Walk us through the landing.
KESTENBAUM: It's sort of like an airplane landing if your airplane were going 25 times the speed of sound and it had lost its power, because once it fires its engines, it's basically falling to earth. It glides a bit, but that's it.
The seats are pretty much coach class. If you're the pilot, you have to be strapped in two hours before you're actually going to be on the ground. They shut the toilets off. See, it's a lot like a flight actually.
And they fire the engines to slow it down and then it gradually falls from orbit; then on the way down, in order to slow down, it fishtails, sort of like if you're a beginner skier, you know, snowplowing down the slope. It swerves from side to side.
On the way down, the astronauts can see a big red glow out the window as if it were on fire, but that's just the heat shields cause they get up to 3,000 degrees. And at the end of the descent there are sonic booms you can hear on the ground.
At the very end it drops 20 times faster than an airplane toward the runway. And then, of course, if you're an astronaut, you feel incredibly heavy because you're back on earth.
KESTENBAUM: It takes about an hour.
MONTAGNE: ...and all of that will happen, as we said, weather permitting. How is the weather?
KESTENBAUM: The official word we got was that the weather looks fairly reasonable.
(Soundbite of laughter)
KESTENBAUM: For some reason they're not very scientific about the forecast for the landing. Actually - I mean, they have pretty strict criteria there because they only have one chance at the landing, obviously. There's no coming around for a second pass.
So they have a rule, for instance, that you can't have rain within 30 miles and that's the one that they seem to be worried about. They have pilots who are flying around the landing strip to check on what the visibility is like and what the conditions are like.
The Shuttle Manager Wayne Hale summarized the orbit - the shuttle's flying characteristics as, it flies like a brick with the handling qualities that would make a Mack truck proud.
They have to get it down by Wednesday, one way or the other. They're going to try - they have two tries today: 9:15, about 9:14 Eastern Time. If they can't land then, they'll take another spin around the earth and try to land at 10:50. If that doesn't work, they'll try tomorrow and they have a backup option at Edwards Air Force Base in California.
MONTAGNE: Well, let's assume everything goes smoothly and talk about what the next mission is.
KESTENBAUM: Well, that would be the shuttle Atlantis, which is sitting in a big garage here getting prepared. And the hope is to launch that at the end of August. And NASA's really hoping that's going to be a return to more routine space flight.
It's going to be bringing up a segment of the backbone for the International Space Station and some solar (unintelligible). NASA wants to get in 16 more flights before retiring the shuttle at the end of 2010. And if their sort of average rate holds from, you know, when the shuttle program was up and functioning at its best, they can do that, they can get in that many flights.
MONTAGNE: And is NASA still planning to use the shuttle to service the Hubble Space Telescope, keep it going?
KESTENBAUM: That is the plan. But one of the reasons they were comfortable launching this time, even though they know they still have a problem with pieces of foam - small pieces coming off during launch - is that, you know, they figured if there were a problem and the shuttle hit something on the way up, the astronauts could always hang out at the International Space Station.
And the Hubble's in a different orbit, so they don't have that option. So they have to feel very comfortable that they understand the debris that's falling off during launch and they have to decide they're okay going to an orbit where astronauts would not be able to get on the Space Station if they were in trouble.
MONTAGNE: David, thanks very much.
KESTENBAUM: You're welcome.
MONTAGNE: NPR's David Kestenbaum speaking to us from the Kennedy Space Center in Florida.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.