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NASA and United Launch Alliance are evaluating a potential problem with the cryogenic propellant system on a Delta II Heavy rocket and will decide early this afternoon whether to make an attempt Saturday to get twin NASA lunar explorers on their way to the moon.
The 12-story rocket and two spacecraft that will map the gravitational field of the moon are tentatively scheduled to blast off from Launch Complex 17B at Cape Canaveral Air Force Station at 8:29 a.m. A second opportunity would come at 9:08 a.m. if need be.
The forecast calls for a 60 percent chance conditions will be acceptable for launch, and routine preparations are continuing as the pad.
"We are proceeding incrementally as if we are going to launch tomorrow," said George Diller, a spokesman for NASA's Kennedy Space Center.
A launch attempt today was called off late Thursday after engineers gathered data that indicated a heater in a Delta II engine section might not be operating properly. The potential problem was detected after supercold liquid oxygen propellant was drained from the rocket's first stage propulsion system after a launch scrub earlier that day.
An initial launch attempt Thursday had been called off as a result of higher-than-allowable upper-altitude winds that could have knocked the rocket off course in flight. The propellant system detanking was part of a normal 24-hour turnaround procedure.
Engineers are evaluating the heater data this morning and will make a recommendation on whether to proceed with a Saturday launch attempt during a meeting early this afternoon.