BY JUSTIN RAY

Follow the countdown and launch of the Lockheed Martin Atlas 2AS rocket with the Japanese Superbird 6 communications satellite. Reload this page for the very latest on the mission.

1845 GMT (2:45 p.m. EDT)

Liftoff of the Atlas rocket and Superbird 6 communications satellite is now six hours away. Activities are progressing as expected this afternoon as technicians work their way through standard pre-launch tests and chores. The navigation test of the rocket's guidance system has just begun.

1745 GMT (1:45 p.m. EDT)

It is a beautiful spring day along Florida's east coast as the countdown continues for this evening's planned 8:45 p.m. EDT (0045 GMT) blastoff of the Atlas rocket from Cape Canaveral's Complex 36.

"I am 100 percent confident the weather will be absolutely perfect for tonight," weather officer Joel Tumbiolo told the pre-launch news conference this morning.

"The inclement weather we had earlier in the week -- Sunday though Tuesday -- is long gone. Looking outside, you see we have clear skies. The winds were a little bit of a concern yesterday, but they also diminished.

"I don't anticipate any weather concerns at T-0 tonight. We will have virtually clear skies, a temperature in the low 60s, a northeast wind in the low-to-mid teens. Again, an absolute zero percent chance of a weather violation for tonight."

You can see latest weather forecast here.

1555 GMT (11:55 a.m. EDT)

START COUNTDOWN. Clocks at Cape Canaveral's Launch Complex 36 are beginning to tick down for today's launch of the Lockheed Martin Atlas 2AS rocket carrying the Superbird 6 communications satellite. Launch is slated to occur at 8:45 p.m. EDT (0045 GMT), the opening of a 33-minute window.

"At 10 o'clock we started charging the batteries," Dave Ryan, president of Boeing Satellite Systems, which built Superbird 6, told reporters at a morning news conference. "The (satellite) right now is working perfectly. We are all looking forward to an excellent launch."

"The weather is going to be absolutely perfect. Everything is working fine on the vehicle," added launch director Adrian Laffitte.

Throughout the day crews at pad 36A and in the Complex 36 blockhouse will proceed through their standard countdown chores needed to ready the Atlas booster and its twin-engine Centaur upper stage for launch, as well as the ground systems and Superbird 6 spacecraft.

Highlights of activities planned, in the order they are scheduled to be performed, include Centaur propulsion launch preps, powering up the rocket's flight control system, Atlas propulsion and hydraulic systems preps, launch pad umbilical tower and mobile service structure preps, performing the flight control operational test, the internal power test of Atlas-Centaur, performing a navigation test of rocket's guidance computer, starting Centaur helium purges and starting liquid hydrogen and liquid oxygen system final preps.

The Integrated Launch Operations -- the final portion of the countdown in which all members of the launch team participate -- will start at 5:30 p.m. EDT (2130 GMT). Retraction of the mobile service tower from around the rocket is slated for 5:45 p.m. EDT.

Countdown clocks will enter a planned 30-minute hold at the T-minus 105 minute mark starting at 6:15 p.m. During this time the launch team will have a chance to catch up on any work that could be running behind schedule.

Fueling operations will commence at 6:59 p.m. with super-cold liquid oxygen flowing into the Centaur upper stage. Loading of liquid oxygen into the Atlas booster stage should start at 7:25 p.m. The final segment of fueling begins at 7:39 p.m. when liquid hydrogen is pumped into the Centaur. The Atlas stage was previously fueled with its supply of RP-1 kerosene propellant.

A final planned hold is scheduled at T-minus 5 minutes for 15 minutes starting at 8:25 p.m. If there are no problems standing in the way of liftoff, the countdown will resume at 5:40 p.m. for an on-time launch.

WEDNESDAY, APRIL 14, 2004

With no problems being addressed and a perfect weather outlook, senior managers have given their approval for Thursday's countdown and launch of the Lockheed Martin Atlas 2AS rocket carrying the Superbird 6 spacecraft from Cape Canaveral, Florida.

"We're looking really good," Atlas launch director Adrian Laffitte said in an interview this morning. "We finished our Launch Readiness Review. We have no open items, no flight constraints, we are working no issues. Everything has gone really well."

The rocket arrived at Cape Canaveral on February 17 from its manufacturing plant near Denver. The Atlas first stage was erected on pad 36A on February 20. All four solid rocket boosters were added one week later. The Centaur upper stage was hoisted atop the first stage on March 1.

After completing initial testing, the team turned its focus to the mid-March the launch of an Atlas 3 rocket with the MBSAT satellite from neighboring pad 36B. Once that mission was successfully flown, attention returned to preparing this Atlas 2AS for the Superbird launch.

A simulated flight was performed March 24, followed by the March 31 Wet Dress Rehearsal countdown test in which the rocket was fueled to practice launch day activities.

Superbird was prepped, fueled and then encapsulated in the rocket's nose cone at a hangar in Titusville. The payload was delivered to the pad and attached to the Centaur on April 7.

Workers had Easter weekend off, and today are putting the final touches on the rocket and buttoning up equipment.

The launch countdown begins at 11:55 a.m. EDT tomorrow. The mobile service tower is scheduled to be retracted from around the rocket at 5:45 p.m. Fueling operations will commence at 6:59 p.m.

The available launch window extends 33 minutes from 8:45 to 9:18 p.m. EDT.

The weather forecast is still predicting a 100 percent chance of favorable weather. You can read all of the details here.

If the launch is delayed for any reason, the available launch window for Friday is 8:45 to 9:18 p.m. The window on Saturday is 8:45 to 9:17 p.m.

We will have live coverage all day long Thursday. Look for our reports beginning around 12 p.m. after the pre-launch news conference and continuing through the countdown and launch of Atlas with Superbird.

TUESDAY, APRIL 13, 2004
1545 GMT (11:45 a.m. EDT)

The weather outlook continues to look impressive as meteorologists predict a zero percent chance of conditions violating the launch weather rules during Thursday evening's launch attempt. See the latest forecast here.

MONDAY, APRIL 12, 2004

Rocketing toward an exceptionally high orbit Thursday evening, a Lockheed Martin Atlas 2AS booster will heave a communications satellite into space to relay television and provide Internet services across the Asia-Pacific region.

Liftoff is scheduled for 8:45 p.m. EDT from pad 36A at Cape Canaveral Air Force Station, Florida. The available launch window extends 33 minutes to 9:18 p.m. EDT.

The early forecast for Thursday's launch opportunity is calling for perfect weather conditions. Air Force meteorologists say there is a 100 percent chance of acceptable weather. See the full forecast here.

The Superbird 6 satellite's home in space is geostationary orbit some 22,300 miles above the equator at 158 degrees East longitude. From that altitude, the craft will match the planet's rotation and appear parked over one spot of the globe.

To each its final destination, the 6,978-pound satellite must first ride the Atlas-Centaur rocket into an egg-shaped supersynchronous transfer orbit stretching from 104 statute miles at its closest to Earth to 74,909 statute miles at the high end, and inclined 25.5 degrees to the equator.

Optimizing the delivery of Superbird into orbit, the launcher will conduct "in-flight retargeting" of its trajectory based on the actual performance achieved and the twin-engine Centaur upper stage is programmed to fire until it depletes its fuel supply.

Deployment of the satellite from the rocket is expected 30 minutes, 5 seconds after liftoff while soaring above central Africa.

The Boeing-built Superbird then takes over control of its journey, using an onboard engine to maneuver into the circular perch 22,300 miles up and removing the orbital inclination.

Space Communications Corp. of Tokyo will operate Superbird 6, putting the satellite into service to replace the aging Superbird A spacecraft launched in 1992. Controllers will rename their new satellite "Superbird A2" once it begins a decade-plus lifetime.

Manufactured upon the Boeing 601 satellite platform, Superbird 6 is equipped with both Ku- and Ka-band transponders to provide a wide-range of services for Japan, Australia, Micronesia, Hawaii, Taiwan, Korea and New Zealand.

"Superbird 6 benefits from a long heritage of innovations and recent improvements in our design, assembly and test processes that have enabled us to provide robust transmission technologies for emerging high-data-rate services," said David Ryan, president of Boeing Satellite Systems.

"This satellite carries a payload with 23 active Ku-band and four Ka-band transponders for high-data-rate communications that will provide television news gathering, distance learning, Internet access, VSAT and other services to customers throughout the Asia-Pacific region."

This launch will be the third Atlas in 2004, the second to use the Atlas 2AS configuration that features four strap-on solid motors. Including Thursday's mission, there are just four Atlas 2- and Atlas 3-series launches remaining to launch from Cape Canaveral's Complex 36. Those vehicle families are being retired in favor of the next-generation Atlas 5 that flies from Complex 41.

Watch this page for live play-by-play updates throughout Thursday's countdown and launch!