Weather Also Poses Potential Conflict

The countdown to the scheduled Tuesday morning launch of space shuttle Discovery on the STS-120 mission is proceeding on schedule, NASA Test Director Steve Payne told reporters Monday. But that doesn't mean all's clear for the shuttle flight.

"At this point in the count, we're on schedule, our systems are all good and we're in great shape," Payne said, adding that the launch team is not tracking any technical issues. However, the weather forecast for Tuesday continues to pose a threat to NASA's launch plans.

Shuttle Weather Officer Kathy Winters reported the seabreeze could begin developing by the 1138 EDT launch time. There is a 60-percent chance that cumulus clouds, showers and a low cloud ceiling could keep Discovery grounded for Tuesday; earlier scheduled launch times for Wednesday and Thursday improve the orbiter's odds of liftoff.

Despite receiving the all-clear to launch last week by NASA mission officials, there are those at the agency who would have preferred to see Discovery stay on the pad, the Palm Beach Post reports, until three worn heat tiles are repaired or replaced.

As ANN reported, three of the 44 reinforced carbon carbon (RCC) tiles that line the edges of Discovery's wings show signs of degradation in their outer coating. Roughly half of the engineers on NASA's shuttle safety team recommended the agency pull Discovery back to the Vehicle Assembly Building, to replace the tiles... adding several weeks to an already tight launch schedule.

Damage to the RCC tiles, caused by a falling chunk of insulating foam from the orbiter's external fuel tank, brought down Columbia in 2003.

After studying the problem, program manager Wayne Hale said last week the agency ruled the issue posed "an acceptable risk," saying the issue has cropped up on past shuttle flights, without leading to catastrophic failure of the shuttle's heat shield.

"There was a great deal of evidence presented, and the preponderance of evidence in my mind says that we have an acceptable risk to go fly," Hale said in an October 16 mission briefing. "And let me make sure you understand that. I didn't say it's safe to go fly and I wouldn't say that. We have an acceptable risk to go fly."

NASA is under the gun to complete the International Space Station, before the shuttle fleet is retired in 2010.

FMI: www.nasa.gov