The launch, scheduled for Saturday, will put into orbit the first Advanced Extremely High Frequency spacecraft, intended to handle the most critical military communications even in the event of a nuclear war, Florida Today reported.
The 13,500-pound satellite is the first in a $6.5 billion program intended to replace the U.S. Air Force's aging Milstar satellites.
Forecasters at Cape Canaveral say conditions for Saturday's launch window appear good, with an 80 percent chance of weather acceptable for launching.
If the launch of the 19-story-tall rocket, with its three strap-on solid boosters, is scrubbed for any reason, officials say, the next attempt would be Monday.
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