Kennedy Space Center, Florida (CNN) -- The space shuttle Endeavour landed at Kennedy Space Center in Florida early Wednesday, completing its 25th and final mission -- the next-to-last mission for NASA's 30-year-old space shuttle program.

"Welcome home, Endeavour," Mission Control in Houston said.

The spacecraft touched down at 2:34 a.m. ET at the end of a nearly 16-day mission to the International Space station.

"It's sad to see her land for the last time, but she really has a great legacy," said shuttle commander Mark Kelly after Endeavour rolled to a stop in the darkness of a warm Florida morning

The youngest of the shuttles retires after 25 space flights. During 299 days in space, Endeavour orbited the earth 4,671 times and logged almost 122.9 million miles, NASA said. It first went into service in 1993.

Endeavour unlocked from the International Space Station late Sunday after spending more than 11 days linked to the orbiting laboratory, where the astronauts installed a cosmic ray detector. The $2 billion, 15,000-pound machine is already at work "gathering information that could improve our understanding of the universe," Kelly said.

"The retirement of Endeavour and the shuttle fleet will not end the human need to explore," Kelly said in comments from space that were posted on NASA's website. "It is and always will be part of who we are. The United States will build other spaceships better than those of today. Even if they are years in the future, they will nevertheless increase our knowledge of the world, generate an enormous benefit to the economy and inspire our children."

On July 8, space shuttle Atlantis is to make NASA's final shuttle flight.

Thousands of people turned out Tuesday night at Kennedy Space Center to watch it make the three-mile trip from the Vehicle Assembly Building to the launch pad.

"Look how majestic it looks rolling out to the launch pad," said astronaut Sandy Magnus to reporters. "Look at that and see what we can do when we put our minds to it."