Launch Countdown Back on Track for Shuttle Atlantis
Remote cameras captured a lightning strike at the launch pad on Friday, Aug. 25, 2006. Photo
Credit: NASA.

CAPE CANAVERAL, Fla. - NASA is pushing ahead with plans to launch its Atlantis shuttle Sunday, though weather remains an ongoing concern for the afternoon space shot.

Atlantis is set to launch six astronauts and a hefty pair of trusses and solar arrays towards the International Space Station (ISS) at 4:30 p.m. EDT (2030 GMT) Sunday, but rain and thunderstorms could thwart the attempt, and lightning has already struck the orbiter's Pad 39B launch site.

NASA test director Jeff Spaulding said the launch countdown for Atlantis' STS-115 mission is currently on schedule, but that analysis is still underway to determine if Friday's lightning strike - which hit the Pad 39B's lightning protection system - affected the orbiter's systems in anyway.

"So far it looks favorable but they are still evaluating as to which direction we need go," Spaulding said the lightning strike checks.

A bolt of lightning stuck one of the metal cables that run from the ground around Atlantis' launch site to the top of a lightning rod on the pad gantry at about 2:00 p.m. EDT (1800 GMT) Friday.

A final analysis will be discussed during a mission management team meeting scheduled for 3:00 p.m. (1900 GMT) today, Spaulding added.

Shuttle weather officer Kathy Winters said NASA is also keeping close tabs on Tropical Storm Ernesto, which is currently gathering strength in the eastern Caribbean and headed into the Gulf of Mexico. A National Weather Service forecast predicts that the storm will gain hurricane status by Monday, and could become a Category 3 storm by late next week.

Shuttle officials said Friday that Ernesto, should it develop into a significant hurricane and follow its current track, could impact NASA's shuttle and ISS mission control operations at Johnson Space Center in Houston, Texas. While it is still too early to predict Ernesto's path, if the storm forces an evacuation of Houston similar to last year's response to Hurricane Rita, Atlantis could return to Earth early.

Spaulding said that should poor weather delay Atlantis' launch over the next several days, flight controllers and mission managers would have to revisit discussions on whether to press forward with the spaceflight while a potential hurricane approaches the Gulf region.

"We have a lot of contingency plans in place if in fact a hurricane does pop up while we're in orbit," Spaulding said.

NASA's STS-115 mission is the agency's first major ISS construction flight since the 2003 Columbia accident.

Weather aside, the launch countdown is back on track now that Atlantis has been loaded with the super-cold fuel cell propellants used to generate electricity for the shuttle during flight. Thunderstorms and lightning delayed the loading process Friday.

At about 5:00 p.m. EDT (2100 GMT) today, some final pieces of cargo - including microbe and yeast experiments - will be tucked away into lockers on Atlantis' middeck. Pad workers expect to roll back the Rotating Service Structure, a shell-like cover protecting Atlantis from this week's stormy weather, at about 7:00 p.m. EDT (2300 GMT), shuttle officials said.

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