* Next landing opportunity at 3:14 p.m. EDT (1914 GMT)
* New crew arrives at International Space Station (Updates with landing delayed)
By Irene Klotz
CAPE CANAVERAL, Fla., March 28 (Reuters) - NASA delayed the homecoming of space shuttle Discovery on Saturday due to concerns about gusting winds and gathering clouds at its Florida landing site.
Flight directors have one more opportunity for a landing attempt on Saturday. If the weather clears, Discovery could leave orbit and touch down at the Kennedy Space Center at 3:14 p.m. EDT (1914 GMT).
"Things are still somewhat variable," astronaut George Zamka radioed to the Discovery crew to tell them to stay in orbit for at least one more pass around Earth.
The shuttle blasted off March 15 for a 13-day construction mission at the International Space Station.
The main goal of the flight, the first of five expected in 2009, was to deliver a fourth set of solar panel wings to the International Space Station, enabling it to house six astronauts on a full-time basis.
They will oversee science experiments in laboratories owned by the United States, Europe and Japan. Canada, which supplied the station’s mobile robotic crane, also has a stake in the program.
To prepare for landing, the Discovery crew closed the 60-foot-long (18-metre-long) doors over the shuttle’s now-empty cargo bay.
The doors have radiator panels to dissipate heat generated by the shuttle’s electrical systems, and once they are closed NASA has limited time to either land the ship or have the astronauts open them again for continued operations in orbit.
While the astronauts waited for a break in the weather, the space station crew was overseeing the arrival of a new group of visitors.
Incoming station commander Gennady Padalka steered his Russian Soyuz capsule into a docking port at 9:05 a.m. EDT (1305 GMT) after taking over manual control when its steering thrusters began firing in a way that would take the Soyuz away from the station, said NASA spokesman Rob Navias.
The Soyuz docked safely earlier than expected.
In addition to Padalka, who is returning for a second stint as station commander, NASA physican-turned-astronaut Michael Barratt and former Microsoft executive Charles Simonyi are aboard the capsule.
Padalka and Barratt will be swapping places with outgoing space station commander Michael Fincke and flight engineer Yury Lonchakov, who are scheduled to return to Earth along with billionaire tourist Simonyi on April 7.
NASA’s next shuttle mission is a servicing call to the Hubble Space Telescope, scheduled for liftoff on May 12. (Editing by Jim Loney and Paul Simao)