A rule prohibits landing if storms, lightning or precipitation are within 30 miles of a landing site.
LONG ISLAND NEWSDAY
CAPE CANAVERAL, Fla. -- Discovery's crew remained in space for an additional day as cautious NASA officials twice waved off landing opportunities at Kennedy Space Center early Monday, citing unstable weather conditions.
That leaves the National Aeronautics and Space Administration with six possible tries this morning at Kennedy, at Edwards Air Force Base in California's Mojave Desert or at the White Sands Space Harbor in New Mexico.
NASA officials said their first preferences would be to try for a 5:07 a.m. or 6:43 a.m. landing at Kennedy, or an 8:12 a.m. touchdown at Edwards. Other potential times are 6:39 a.m. or 8:13 a.m. at White Sands or 9:47 a.m. at Edwards.
Unsettled conditions were again forecast for Florida's central coast, with a slight chance of showers offshore, while the weather in southern California appeared more promising. The mission has a cushion of at least two days in case of weather-related delays, including Monday's postponement.
Kennedy Space Center chief weather officer John Madura expressed confidence of a landing this morning. " ... they will land somewhere. That's the plan," Madura said.
Officials have tilted toward Florida landings, since every California touchdown costs the cash-conscious space agency an estimated $1 million to transport the shuttle back to Kennedy, piggybacked atop a modified 747 jumbo jet.
After Monday's first delay, called at 3:17 a.m. by Mission Control officials in Houston, Madura said his team could have easily made a more favorable forecast of scattered clouds. "But were we confident enough to bring the shuttle home? No," he said.
NASA engineers and flight controllers have repeatedly exercised caution during the mission, one of the most heavily scrutinized in the shuttle program's history and the first since the Columbia shuttle disintegrated during its landing attempt Feb. 1, 2003.
Nevertheless, an unexpected foam-shedding event seen during Discovery's ascent and two protruding gap fillers observed on the vehicle's belly -- later removed during an unprecedented space walk -- have prompted a stream of safety questions.
The space center's weather flight rules prohibit landing if a thunderstorm, lightning or precipitation occurs within 30 nautical miles of the landing site.
By 3 a.m. Monday, the clouds had begun to dissipate. The shuttle crew had donned their bright orange launch and entry suits and strapped themselves into their seats in anticipation of a "de-orbit burn," when commander Eileen Collins and pilot Jim Kelly would have fired braking rockets to drop Discovery out of orbit and lock into a downward trajectory.
But Mission Control waved off the first landing opportunity, scheduled for 4:47 a.m., because low broken clouds threatened to obscure Kennedy's three-mile runway.
As he waited by the three-story viewing platform overlooking the landing strip, astronaut John Herrington recalled being delayed from landing for four days due to weather while aboard mission STS-113.
"I think I suited up four times," said Herrington. But he added that the delays didn't faze the Endeavor crew. The extra days gave him a welcome chance to reflect on his time in space, he said.