HARI SREENIVASAN: The final mission for space shuttle Discovery lifted off this afternoon from Cape Canaveral, Fla. It's carrying six crew, cargo and a robot assistant to the International Space Station, 220 miles from Earth.
Discovery and the other two shuttles, Endeavour and Atlantis, are being retired because of high costs.
We caught up with NewsHour science correspondent Miles O'Brien at Kennedy Space Center. He has attended almost 40 shuttle launches. I asked him about the legacy of Discovery and the space shuttle era.
MILES O'BRIEN: Discovery has flown the most missions, and you could argue the most significant missions, both return to flights after the Challenger and Columbia disasters, the deployment of the Hubble space telescope, numerous other significant events along the way, the second flight of John Glenn into space, after his long time away from space, after being the first American to orbit the Earth.
HARI SREENIVASAN: Now, this is -- when we look at the bigger picture of the space shuttle program, when they originally designed it, they thought it was actually going to be making money. But what was the promise that we had with space shuttles versus what they delivered?
MILES O'BRIEN: Well, the promise of the space shuttle program, when you look at how they were selling it in the front of Congress, was just pure fancy.
There were all these studies which indicated the space shuttle fleet could be flown on the order of once a week, and that it would have airliner-like capability for turning it around once it got on the ground.
But it's an incredibly complicated system. And there wasn't a full appreciation at the time for really how difficult it was to fly a reusable spacecraft to and from space. NASA was trying to meet that promise. And then, of course, we lost Challenger 25 years ago.
HARI SREENIVASAN: All right, so what happens to Discovery next? I mean, when you see some of the most recent pictures, it looks like kind of worse for wear. It's just like -- that it's been through the wringer.
MILES O'BRIEN: Yes, it looks like Han Solo's spacecraft from "Star Wars." It's a little bit singed, frankly.
And it's been through the mill. It's got many millions of miles on the odometer, as it were. And those -- those heat-resistant tiles, some 20,000 of them that envelope the space shuttle and keep it safe for its crew, assuming all goes well, when it comes back in for reentry, they get singed.
And so, when you get close to an orbiter, you suddenly realize that it's been through the mill, so to speak. It's not pristine on the outside. Now, you go on the inside, and it's got that new car smell. They do a very nice job of turning these things around and making them as new as they can possibly be.
You know, they were certified -- each orbiter was certified for 100 flights on the airframe. And this will be the 39th flight for the space shuttle Discovery. So, in theory, she could go on for a long time.