NASA monitors weather, preps Atlantis for Friday launch (UPDATED)

Editor's note...
  • Posted at 03:27 PM EDT, 07/07/11: NASA monitors threatening weather, preps Atlantis for Friday launch
  • Updated at 04:00 PM EDT, 07/07/11: Engineering review board ordered to assess lightning strike
  • Updated at 06:00 PM EDT, 07/07/11: Initial review finds no issues with lightning strikes
CBS News

Stormy weather from a tropical wave rolled across Florida Thursday, bringing heavy rain to the Kennedy Space Center where the shuttle Atlantis is being prepared for launch Friday on NASA's final shuttle mission. Forecasters are predicting a 70 percent chance of a weather-related launch delay. (Credit: NASA TV)
KENNEDY SPACE CENTER, FL--As predicted, thunderstorms rumbled across the Kennedy Space Center Thursday and two lightning bolts struck on or near launch pad 39A where the shuttle Atlantis is being prepared for takeoff Friday on NASA's 135th and final shuttle mission.

Magnetic field readings at the pad exceeded normal limits in four locations, prompting engineers to review telemetry to make sure no sensitive systems were affected. Sources said a preliminary assessment found no major problems and while additional data reviews were planned, engineers did not expect to need any time-consuming system re-tests.

Regardless of the lightning strike, forecasters predicted a 70 percent chance of stormy weather that could trigger a launch delay Friday. The forecast improves slightly to 60 percent "no go" Saturday and 60 percent go on Sunday, the final day in the shuttle's current launch window. But NASA managers may be able to get an additional launch opportunity Monday if the Air Force agrees to delay launch of a navigation satellite.

If so, and assuming the lightning assessment remains positive, NASA's mission management team could opt to press ahead for a Friday launch or stand down in favor of two attempts between Saturday and Monday when the weather should be improving.

"Weather is not looking good for launch," shuttle weather officer Kathy Winters told reporters during a morning briefing. "As you can see outside, the clouds have rolled in, we're starting to see some showers. We even had a thunderstorm show up this morning. So we are expecting more of this for the next couple of days."

Threatening clouds over the Kennedy Space Center Thursday. (Credit: NASA TV)
Later in the day, another thunderstorm pounded the space center, bringing torrential rain and lightning. Telemetry in the launch control center indicated two lightning strikes, one on the pad and another a little more than a half mile away, triggering inspections and a data review to make sure systems that were powered up at the time were not affected.

Running about 45 minutes behind schedule, engineers began rolling a huge protective gantry away from Atlantis Thursday afternoon, exposing the shuttle to view and setting the stage for fueling early Friday. NASA's mission management team planned to meet at 1:30 a.m. EDT (GMT-4) Friday to assess the weather and any unresolved technical issues. Assuming managers decide to proceed, engineers will begin loading a half-million gallons of liquid oxygen and hydrogen rocket fuel into Atlantis' external tank at 2:01 a.m.

The three-hour fueling procedure should be complete by around 5 a.m. and if all goes well, commander Christopher Ferguson, pilot Douglas Hurley, Sandra Magnus and flight engineer Rex Walheim will begin strapping in for launch around 8:06 a.m. Liftoff is targeted for 11:26:46 a.m.

Between 500,000 and 750,000 spectators are expected to turn out for NASA's final shuttle launch, complicating NASA's scrub-turnaround plans. If the weather or some other problem triggers a delay in the last four hours of the countdown, Launch Director Mike Leinbach likely will order a 48-hour delay because of concern the launch team would not be able to make it home through expected heavy traffic and get back to the space center in time for a launch try the next day.

As a result, a launch scrub Friday likely would delay a second attempt to Sunday.

Going into the launch campaign, NASA managers said Atlantis had to be off the ground by Sunday or the flight would slip to July 16 to make way for launch of a military navigation satellite from the nearby Cape Canaveral Air Force Station. But if the Air Force agrees to a one-day slip, NASA could get a fourth launch opportunity Monday. How that might play into the decision to proceed with a Friday launch try remains to be seen.