The space shuttle Endeavour and its crew returned safely to the Kennedy Space Center in Merritt Island, Fla., at 2:35 a.m. EST this morning, completing the 134th and penultimate flight of the 30-year-old space shuttle program.
The six member crew of NASA's second-to-last shuttle flight -- which included Cmdr. Mark Kelly, who is returning to his wife, shooting victim Congresswoman Gabriel Giffords -- returned to Earth securely after a 16-day mission.
"The space shuttle is an amazing vehicle to fly though the atmosphere … on behalf of the entire crew I want to thank all of the people that worked on the mission," Kelly said upon landing.
"It is sad to see her land for the last time, but she really has a great legacy," he added.
After a smooth unlocking from the International Space Station late on Sunday, Kelly steered the shuttle through critical re-entry and the long glide over the Pacific Ocean, Central America, the Gulf of Mexico and into Florida, according to NASA; Astronaut Greg H. Johnson is the shuttle's pilot.
The astronauts, all veterans of previous flights, added the last major components to the U.S. section of the International Space Station, including the delivery of a $2 billion cosmic ray detector, called Alpha Magnetic Spectrometer-2 (AMS), which will remain mounted on the space station for the next decade.
The cosmic ray detector will be searching for antimatter and dark matter, which scientists hope will shed light on the origins of the universe. The AMS will prove -- or disprove -- the Big Bang Theory of how our universe was born.
There is only one more flight on the decades old shuttle schedule, on July 8 by the shuttle Atlantis -- which will bring a close to the 30-year program. Atlantis' flight will be a less scientifically significant mission -- a two day haul to the space station.
On the misison, a crew of four -- "The Final Four," they have dubbed themselves -- will stuff the space station with as much equipment, food and miscellaneous items as the orbiter can carry up.
Kelly almost gave up his final opportunity to fly in space, but was finally persuaded his wife was in good hands and would want him to go. She underwent a successful cranioplasty surgery in Houston two weeks ago, after his launch, to replace bone that was lost after the shooting.
"I think it was the right decision. She was ready for the surgery," Kelly told ABC News in an interview on Monday.
Endeavour's Impressive PastThe space shuttle Endeavour was commissioned as a replacement for the Challenger spacecraft after permission to build was granted by Congress on August 1, 1987. It arrived at the Kennedy Space Center's shuttle landing facility in May of 1991, and began flight operations in 1992.
On previous flights, the Endeavour's crew has repaired disabled satellites, worked on cutting edge, if sometimes goofy medical experiments -- pregnant frogs, for example -- and even flew a Coke machine that didn't quite work.
Over its lifetime, the shuttle racked up an impressive scorecard: 299 days in use, 4,671 orbits, 172 crew members and a whopping 122,853,151 miles.
One of the shuttle's crews staged the only three person spacewalk, in order to grab a slippery satellite. It's most spectacular mission was when it flew into high orbit and had the nation sitting on the edge of its seat when it repaired the crippled Hubble Space Telescope.
After Endeavour lands, it will be "safed" by engineers -- engines and explosive bolts will be removed, and traces of toxic fuel will be cleared from its plumbing. It will ultimately go on display in a Los Angeles museum.
And what next for the space program, after Atlantis? NASA may plan for trips to asteroids and, eventually, to Mars. Outer space enthusiasts are already speaking of the time of the space shuttle in the past tense, though, as the end of the era quickly approaches.