The Associated Press
EDWARDS AIR FORCE BASE, Calif. Ä Endeavour and seven astronauts touched down in California's Mojave Desert on Saturday, ending a 16-and-1/2-day stargazing mission, the longest flight in shuttle history.
Commander Stephen Oswald guided Endeavour through clear skies to an Edwards Air Force Base landing at 4:47 p.m. EST, 16 days, 15 hours after the crew blasted off from Cape Canaveral, Fla.
The astronauts traveled 6.9 million miles and circled Earth 262 times during NASA's 68th shuttle flight, Endeavour's eighth.
The longest previous shuttle flight was 14 days, 18 hours by Columbia last summer.
''Welcome home Endeavour after a fantastic record-setting mission. It will be a tough one to beat,'' Mission Control's Curtis Brown told the crew after Endeavour rolled to a stop on the runway. ''It sure is nice to have you all home.''
''It's nice to be here,'' Oswald replied.
More than 1,000 spectators filled a viewing stand and another 100 VIPs, including crew members' families, watched the afternoon landing. NASA officials made last-minute arrangements for Administrator Daniel Goldin, accompanied by two daughters and a grandson, to witness the landing.
Goldin earlier in the week had been at NASA's Ames Research Center in Mountain View, Calif.
Goldin greeted Oswald and two other astronauts Ä Wendy B. Lawrence and William G. Gregory Ä in the bright sunshine while they still were in their orange flight suits and getting their land legs.
The astronauts were scheduled to fly to Houston on Sunday after extended medical evaluations, said NASA spokesman Don Haley.
Stormy weather in Florida thwarted attempts both Friday and Saturday to return the shuttle to its home base. Besides slight crosswinds, the weather at Edwards was good, with high scattered clouds. Wind kicked up swirling dust from the dry lake bed that surrounds the concrete runway.
As the shuttle made its final approach, its twin sonic booms were felt throughout the Los Angeles area.
NASA prefers returning shuttles to the Kennedy Space Center because it costs $1 million to ferry them across the country atop a modified jumbo jet. It also adds about a week to the turnaround time shuttles require before they fly again.
Endeavour's next flight is in July. The craft should begin its piggyback return trip by Thursday, Haley said.
Endeavour was launched March 2 with a $200 million observatory in the cargo bay. The astronauts, including four astrophysicists, worked 24 hours a day in two shifts to point three ultraviolet telescopes toward the heavens.
Some 600 galaxies, stars, planets and moons were included on astronomers' target list. The mission ultimately yielded ultraviolet spectrum data and photographs of about 300 celestial objects.
Throughout the flight, one of the telescopes stared at a quasar 10 billion light years away in search of intergalactic helium that would support the big-bang theory.
Scientists believe hydrogen and helium were spread among the galaxies when an immense explosion created the universe. If there's no primordial helium out there, parts of the big-bang theory might have to be reconsidered.
Astronomers used the quasar as a light bulb to see whether anything was blocking its ultraviolet light. Any such substance could be intergalactic helium.
The shuttle instruments teamed with the Hubble Space Telescope for an in-depth study of Jupiter and how the giant planet's atmosphere is affected by volcanic eruptions on one of its moons, Io.
The flight also yielded the first ultraviolet pictures of our moon. Astronomers hope 70mm images collected over the past week will lead to new ways of studying other planets, moons and asteroids in the solar system.
Oswald chatted via ship-to-ship radio with former crewmate Norman Thagard, who this week became the first American aboard Russia's Mir space station.
The shuttle crew became part of the largest human contingent ever in space Ä 13 Ä when Thagard and two cosmonauts were launched in a Soyuz capsule from Kazakhstan last Tuesday. There were already three cosmonauts aboard Mir at the time.
The next shuttle flight is scheduled for early June, when Atlantis will dock with Mir and pick up Thagard and two cosmonauts. It will drop off two other cosmonauts as replacements.