The countdown continues… NASA reports:

STS-115 Countdown Status Briefing
STS-115 Commander Brent Jett boards the Shuttle Training Aircraft this morning, to practice landing the shuttle. The STA simulates the atmospheric flight characteristics of the Orbiter. NASA PHOTO NO: KSC-06PD-2025At the 10 a.m. EDT countdown status briefing on Monday, all systems were reported “go” for the scheduled launch of Atlantis on Wednesday at [12:29PM EDT].

Jeff Spaulding, NASA test director, said that the loading of both the liquid hydrogen and liquid oxygen has been completed and they are “tracking no issues at this time and we’re right on track with all of our timelines.” Spaulding indicated that the retraction of the rotating service structure is currently planned for 3 p.m. on Tuesday. Spaulding said, “I’m pleased to announce that the wait is nearly over and we’ll be ready on Wednesday for Atlantis’ launch.”

Robbie Ashley, STS-115 payload manager, explained that the STS-115 payload had “no work planned or required during the delay” and that the only payload work remaining would be an experiment stow on Tuesday.

Kathy Winters, shuttle weather officer, reported favorable weather for the midday launch time on Wednesday, with only 20 percent chance of weather interfering with liftoff.

Later today, NASA TV will also carry the Launch Readiness News Conference live from Kennedy. Updating the launch status and answering questions from the media will be LeRoy Cain, launch integration manager, Mike Leinbach, shuttle launch director, and U.S. Air Force First Lt. Kaleb Nordgren of the 45th Weather Squadron at Cape Canaveral Air Force Station. Coverage will begin at approximately 4 p.m.
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The countdown officially began at 8 a.m. Sunday, at the T-43 hour mark, which includes over 30 hours of built-in hold time prior to a targeted 12:29 p.m. launch on Wednesday. The launch time is the middle point in the launch window that extends for 10 minutes.

Check the links at right for play-by-play and NASA TV.