The Atlas 5 rocket on the move from the pad to Vertical Integration Facility on Wednesday. Photo: Justin Ray/Spaceflight Now

Lockheed Martin's next-generation Atlas 5 rocket cleared its last major launch pad test this week, putting the vehicle on course to begin final preparations for blastoff on the much-anticipated inaugural voyage August 12.

Sitting atop it's mobile launch platform, the rocket was moved from the Vertical Integration Facility assembly building to the open-air pad at Cape Canaveral's Complex 41 on Monday for the third and final countdown dress rehearsal.

On Tuesday, the launch team conducted a complete countdown and fully fueled the rocket. Technicians followed the launch day timeline to realistically demonstrate how the countdown will be run.

"We performed this test exactly the way we will do the launch countdown, except that we did not lift off at T-zero," said John Karas, vice president of Atlas 5 development. "With three successful rehearsals, the team is confident we're ready to begin the final preparations for launch."

"We had a lot of little things that crept up, nothing major," Atlas launch director Adrian Laffitte said of Tuesday's countdown. "As we knew this was our last Wet Dress Rehearsal, we were just very cautious. We were checking everything, double-checking everything."

Workers on Wednesday safed the rocket and then rolled it back to the Vertical Integration Facility where it will remain until August 11. The nose cone and mass simulator that has been atop the rocket for all three countdown tests will be removed in the days ahead.

Managers and engineers will spend the next couple of weeks reviewing paperwork and documentation to ensure everything is ready for launch.

"There is a lot riding on this vehicle and we want to make sure we have done reviews of the reviews," Laffitte said.

Meanwhile, at the commercial AstroTech spacecraft processing facility in nearby Titusville the Atlas 5 rocket's cargo -- the Eutelsat Hot Bird 6 direct-to-home TV broadcasting satellite -- is undergoing its last checks.

Lockheed Martin has given the spacecraft team a "go" to mount the satellite atop its payload adapter this week, which is the precursor to encapsulation of the Alcatel Space-built craft inside the rocket's two-piece nose cone.

Once shrouded in the fairing, the satellite will be trucked to the Vertical Integration Facility and mated to the Atlas 5. The joining of spacecraft and rocket is targeted for August 1.

Testing of the completed launcher and cargo will follow.

After rolling back to the pad on August 11, the first stage will be re-loaded with its supply of RP-1 propellant, a highly refined kerosene, and auto-coupling connections between the pad and launch platform will be engaged in preparation to load the cryogenic liquid oxygen and liquid hydrogen into the vehicle during the final hours of the countdown.

The launch window on August 12 opens at 6:09 p.m. EDT and extends for 83 minutes to 7:32 p.m. EDT.

Lockheed Martin has secured August 13 and 14 as backup launch days, if needed. The launch time would be 6:08 p.m. on August 13 and 6:09 p.m. on August 14.