NASA delays launch of Endeavour shuttle

CAPE CANAVERAL, Fla. -- Thunderstorm clouds forced NASA to call off Thursday's launch of space shuttle Endeavour on a mission to deliver a new crew to the international space station and fix the orbiting outpost's robot arm.

Launch managers said they will try again this evening, even though the weather was expected to worsen.

The delay means yet another day in orbit -- and a record-breaking stay -- for Americans Daniel Bursch and Carl Walz. They have been living aboard the space station since December along with their Russian commander, Yuri Onufrienko.

Their mission, already at the 176-day mark, will reach at least 189 days by the time they return to Earth. The U.S. space endurance record stands at 188 days; Shannon Lucid posted that aboard Russia's Mir space station in 1996.

"I'm sure that Dr. Shannon Lucid will congratulate them on that particular feat when they finally do return home," said NASA Administrator Sean O'Keefe. Mission Control radioed up its own congratulations Thursday night.

Onufrienko has an even longer mission to his credit: a 193-day Mir flight in 1996. That's still far short of the 438-day world record held by his fellow countryman, Valery Polyakov.

The delay came as no surprise to the seven astronauts and cosmonauts aboard Endeavour. Approaching thunderstorms had threatened to postpone the flight all day. The launch team also had to deal with a fleeting problem with one of Endeavour's orbital-maneuvering systems that cropped up.