As Lockheed Martin's Atlas 5 rocket was passing a comprehensive engineering review this week, spacecraft teams were getting set to resume final pre-flight preparations on the French-built Hot Bird 6 satellite to be carried into space during the launcher's maiden voyage on August 21.

The Atlas 5 rocket on the launch pad earlier this year during a countdown rehearsal. The Vertical Integration Facility can be seen in the distance on the left. High-pressure gas storage tanks are in the foreground. Photo: Lockheed Martin

The formal "President's Review" was held Wednesday to give G. Thomas Marsh, president and general manager of Lockheed Martin Space Systems - Astronautics Operations, and other key officials a thorough presentation on the status of the Atlas 5. The review concluded with a "go" to press ahead with launch activities.

Liftoff from Cape Canaveral's Complex 41 had been scheduled for August 12, but was postponed 9 days at the request of the customer. The Hot Bird 6 direct-to-home TV broadcasting satellite, built by Alcatel Space for operator Eutelsat, is inside the AstroTech processing facility in nearby Titusville. Work to ready the spacecraft was recently suspended for unspecified reasons, but whatever caused the satellite to get behind in the launch campaign has been resolved, officials said.

The craft is expected to be fueled in the next few days, followed by its encapsulation within the two halves of the rocket's nose cone on August 7 or 8. The satellite then will be transported a few miles to the Vertical Integration Facility at Complex 41 -- the Atlas 5's vehicle assembly building. Once at the VIF, the satellite will be hoisted up and bolted to the rocket's Centaur upper stage on August 9 or 10.

The Integrated Systems Test -- the major check of the combined rocket and satellite -- is slated for August 13.

If all goes well, the Atlas 5 will be rolled from the VIF to the open-air launch pad on August 20 to kick off the final countdown to liftoff. After the mobile launching platform is firmly in position at the pad, RP-1 kerosene fuel will be loaded into the rocket's first stage and auto-coupler connectors will be engaged to feed cryogenic liquid oxygen and liquid hydrogen to the rocket the next day. The rocket and pad systems are then secured for the night.

The launch day countdown will last just over 10 hours. The day begins with powering up the Atlas first stage and Centaur upper stage, followed by guidance system testing. As clocks tick down, several hours are spent going through a list of other tests and checks.

After a half-hour planned hold in the countdown at T-minus 170 minutes, work will begin to load the liquid oxygen into Atlas at T-minus 135 minutes and then Centaur at T-minus 122 minutes. Hydrogen tanking for Centaur begins at T-minus 67 minutes. A final 10-minute built-in hold is planned at T-minus 4 minutes.

The launch window on August 21 extends 89 minutes from 6:05 to 7:34 p.m. EDT (2205-2334 GMT).

Lockheed Martin has booked August 22 and 23 for backup launch opportunities on the Eastern Range, if needed.

For future Atlas 5 missions, Lockheed Martin hopes to compress the timelines in order to roll the rocket to the pad and launch it about 14 hours later. But managers say they are focused on conservatism and taking things slow for this inaugural launch.