Discovery caps mission with smooth landing

CAPE CANAVERAL, Florida (Reuters) - The space shuttle Discovery landed safely at its Florida home base on Wednesday after a grueling but successful 15-day construction mission that prepared the International Space Station for new laboratories.

Gliding through crisp, clear skies, the shuttle settled onto a concrete, canal-lined landing strip at the Kennedy Space Center at 1:01 p.m.

Double sonic booms rang through central Florida as the shuttle neared the end of its trek of 6.2 million miles that began with its launch on October 23.

Commander Pamela Melroy, only the second woman in NASA's 50-year history to land a spaceship, took over manual control with 50,000 feet to go, gently steering the 100-tonne shuttle through sweeping curves to burn off speed.

"Congratulations on a tremendous mission and a great landing, Pam," astronaut Terry Virts radioed to the crew from Mission Control in Houston when Discovery rolled to a stop.

During 11 days at the space station, the Discovery crew delivered and installed a new module, named Harmony, that will be the connecting node for Europe's Columbus and Japan's Kibo laboratories.

Deliveries of both labs are running about five years behind schedule due to station construction delays, first by Russia and more recently by the United States, which grounded its shuttle fleet for 2-1/2 years after the 2003 Columbia disaster. The shuttles are the only spacecraft capable of carrying some of the large station parts.

NASA ditched two of the five spacewalks planned during Discovery's mission and added an emergency outing to salvage a broken solar wing panel on the station.

The live-aboard station crew, which includes newly arrived flight engineer Dan Tani, faces a daunting month of work to prepare the outpost for Columbus' arrival next month.

NASA hopes to launch Europe's lab on December 6. The launch window extends only until about December 13.

The U.S. space agency is scrambling to complete 11 construction missions, two resupply flights and a final upgrade to the Hubble Space Telescope before the shuttle fleet is retired in 2010.

IMPROVISED REPAIR

NASA's station expansion plans were almost derailed by a solar power panel that tore in two places as it was being unfurled last week.

Astronaut Scott Parazynski made an unprecedented spacewalk to the furthest reaches of the station to perform an improvised repair to the 110-foot (33-metre) panel.

The successful fix prevented a power shortage and station stability problems that would have threatened future construction, NASA said.

Tani remained at the space station, trading places with Clay Anderson, who returned after a five-month stay.

(Additional reporting by Jeff Franks in Houston, editing by Michael Christie and John O'Callaghan)