Mission Accomplished

Space shuttle Endeavour returned to Earth Monday, completing NASA's fifth and final shuttle flight this year, reports CBS News Space Consultant William Harwood.

As the international space station shined bright in the night sky above Kennedy Space Center — powered by a new solar array delivered by the shuttle's crew — Endeavour took a sweeping left overhead turn, lined up on runway 15 and swooped to a high-speed touchdown at 6:03:25 p.m., 11 days and nearly 4.5 million miles since blastoff Nov. 30

The crew completed a crucial and challenging task during its 11 days in space: delivering, installing and then fixing twin solar wings needed to power the new space station — the most powerful solar arrays ever launched.

The $600 million solar wings — the largest and most powerful ever built for a spacecraft — are already generating up to 42 kilowatts of electricity for the three men on board. It will power the orbiting outpost for years to come.

Until the new solar wings were installed one month into their four-month mission, the three crew members had to skimp on electricity. When Endeavour deployed them, the cables that held blankets or solar cells to one of the wings snapped. Working against the clock, NASA had to test a process for repairing the wings on the ground and radio it to the astronauts hovering above Earth.

The repairs were successful.

During the mission, five Endeavour astronauts visited the three space station crew members — Bill Shepherd, a NASA astronaut who has lived aboard the station for more than a month, and his two Russian crew mates, Sergei Krikalyov and Yuri Gidzenko.

Shepherd and his Russian crewmates have been aboard Alpha since Nov. 2. They will remain there through late February.

Endeavour made it home despite concerns over weather conditions.

Throughout the afternoon, NASA worried clouds or rain might delay Endeavour's homecoming. The possibility of bad weather earlier in the day had prompted NASA officials to activate Edwards Air Force Base, Calif., as a secondary landing site.

NASA does not like shuttles to fly through rain because their speed — twice that of a military jet as their wheels touch the runway — could cause even a gentle shower to damage the protective tiles covering the spacecraft.

But while Endeavour's landing went smoothly, its launch revealed problems that could affect the next shuttle due to visit the space station — shuttle Atlantis, which will deliver and install the American lab Destiny in January.

Atlantis was to have been rolled out onto the launch pad Monday in Florida to begin preparations for takeoff, but that was delayed until at least Wednesday as engineers troubleshoot a problem that discovered during Endeavour's launch.

NASA says an explosive booster separation bolt failed to fire for Endeavour on November 30, and figuring out why that happened is now part of the preparation for the Atlantis takeoff.

A redundant system did fire and the side-rocket fell into the Atlantic Ocean as it was supposed to do, and was recovered by ship. Had both systems failed and the rocket not separate, the Endeavour crew might have been forced into a risky and unproven abort scenario.

Preliminary inspections indicate a broken wire in an electrical component on the booster may have been responsible for the failure, rather than a problem with the detonator itself.

NASA considers that good news: replacing or inspecting detonators would have required taking the shuttle and its external tank off the two boosters to gain access.

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