Discovery Shuttle  Its Final Landing

Space shuttle Discovery came down from a blue Florida sky, turned gracefully and made its last-ever landing today at the Kennedy Space Center in Florida.

It was a quiet end to an almost flawless 13-day mission, and a storied career for NASA's most-flown shuttle. Landing came at 11:57 a.m ET.

Sweetheart of the fleet, workhorse, rock star. Whatever words are used to describe Discovery, they don't seem to tell her story adequately.

The numbers tell the factual story: 39 missions, 365 days in space, 5,830 orbits of the Earth, 148,221,665 miles traveled. It has gone through 39 sets of landing-gear tires since its first flight in 1984.

But what did Discovery accomplish beyond the numbers? Nicole Stott, one of the astronauts on Discovery's final mission, said Discovery is remarkable.

"It is kind of cool that the vehicle named Discovery has this kind of history, the most flights," she said in a preflight interview with ABC News. "I think it really sums up what the space program is about -- it is about discovery."

Discovery flew both return-to-flight missions after its sister ships, Challenger and Columbia, were lost. It launched the Hubble Space Telescope. It carried John Glenn, one of America's first space pioneers, on his sentimental return to space in 1998. It assembled the first components of the International Space Station. It has flown more times than any other spaceship in history.

"Without Discovery, and the other space shuttles, we would not have built the space station," said Leroy Cain, NASA's deputy space shuttle program manager, who marveled how a 900,000 plus pound orbiting lab was assembled on orbit, thanks to the space shuttle. "Nothing else has the capability to carry up those big modules, and the parts needed to keep it functioning, it is truly a remarkable spacecraft."

The surviving space shuttles -- Discovery, Endeavour and Atlantis -- are being retired this year. They are 30 years old fleet, and not capable to going beyond low Earth orbit. What is the next-generation spacecraft? Nobody is sure. Commercial companies such as SpaceX, Orbital Sciences, Boeing and Lockheed Martin are competing with NASA to design new ships that will launch humans and cargo into space.