Uncertain weather over Kennedy Space Center, Fla., forced NASA to abandon its first attempt to launch the Ares I-X demonstration and test vehicle Oct. 27, so the agency is targeting another attempt Oct. 28.

Countdown to launch, originally set for 8 a.m. Eastern time, at one point came within 2 minutes 38 seconds of liftoff until clouds came too close to Launch Pad 39B.

The hold came at the end of a sequence of delays that began when launch personnel attempted to remove the cover of the "five hole" nose probe on the rocket, which measures air speed, pitch and yaw angles, and the total and static pressure during the flight. For some time the cover stubbornly refused to move - the first time such an issue had been seen "after hundreds of tests," according to launch officials.

But no sooner had the cover been removed, when a cargo ship wandered into the safety zone downrange of Kennedy Space Center. There was brief uncertainty over how long it would take for the ship to leave the danger area before the errant vessel was ordered to turn around, and quickly became no factor.

With vehicle conditions all nominal for launch, weather again intervened when a 45th Space Wing and observer aircraft, during a final pass over the launch site, noted cloud encroaching over the edge of the pad area. As these clouds indicate the potential presence of "P-static" (P for precipitation), which can create a corona that interferes with radio signals sent by or to the rocket, this was considered a "no-go" condition. The P-static issue is critical as it could interfere with flight termination signals sent by the Range Safety Officer at Cape Canaveral Air Force Station in the event of a malfunction.

With no signs of improvement in the weather and winds gusting above the 20 knot launch limit, NASA finally made the decision to scrub at 11:21 a.m. Eastern time. The window for the launch was due to close at noon.

Ares I-X photo: NASA