BY JUSTIN RAY

Follow the countdown and launch of the Lockheed Martin Atlas 3A rocket with the MBSAT mobile broadcasting communications satellite. Reload this page for the very latest on the mission.

THURSDAY, MARCH 11, 2004

After resolving last-minute insurance issues, builder of the MBSAT mobile broadcasting satellite has affirmed plans to launch the craft in the predawn hours Saturday atop a Lockheed Martin Atlas 3A rocket. Read our full story.

2235 GMT (5:35 p.m. EST)

Go for launch! Officials have approved plans to launch the MBSAT spacecraft on Friday night/Saturday morning. Liftoff is scheduled for 12:40 a.m. EST (0540 GMT). Weather forecasters are calling for a 100 percent chance of favorable conditions.

1915 GMT (2:15 p.m. EST)

The MBSAT mobile broadcasting satellite could be grounded until at least summer if its builder cannot resolve last-minute insurance issues before the available window in the Atlas rocket launch schedule closes Saturday. Read our full story.

We will update this page as soon as information becomes available this evening.

1615 GMT (11:15 a.m. EST)

Forecasters continue to predict a 100 percent chance of acceptable weather for the Friday night/Saturday morning launch attempt of Atlas 3 carrying the MBSAT mobile communications satellite. See today's updated forecast here.

WEDNESDAY, MARCH 10, 2004
2125 GMT (4:25 p.m. EST)

Space Systems/Loral, the builder of MBSAT, requested that Friday morning's launch attempt be postponed one day. No specific information has been released about the reasons behind the delay.

Pending resolution of Loral's constraints, liftoff of the Atlas 3A rocket will occur Friday night/Saturday morning at 12:40 a.m. EST (0540 GMT). The available launch window extends 90 minutes.

Lockheed Martin says the Atlas vehicle remains in good shape with no issues or concerns.

The launch countdown is slated to commence at 3:50 p.m. EST (2050 GMT) on Friday.

1643 GMT (11:43 a.m. EST)

DELAY. Launch of the Atlas 3A rocket and MBSAT spacecraft has been pushed back 24 hours. Saturday's predawn launch window extends from 12:40 to 2:10 a.m. EST (0540-0710 GMT). There is a 100 percent chance of favorable weather for the liftoff attempt.

Details about the problem that forced this 24-hour postponement have not yet been formally announced. We'll update this page as additional information is released.

1500 GMT (10:00 a.m. EST)

It is a rarity for Cape Canaveral launches not to worry about the fickle Florida weather, which often provides drama during countdowns. In the latest forecast for tomorrow night's Atlas 3 launch, meteorologists are now predicting a 100 percent chance of favorable weather. Officials have removed the 'less than 10 percent chance' of showers that had been in the forecast earlier. It is unusual for meteorologists to take away any doubt of weather hiccups this far in advance. See today's updated forecast here.

TUESDAY, MARCH 9, 2004
1420 GMT (9:20 a.m. EST)

Meteorologists are now expecting less than a 10 percent chance of conditions violating the launch weather rules Friday morning. See today's updated forecast here.

0501 GMT (12:01 a.m. EST)

Lockheed Martin's next-to-last Atlas 3 rocket is ready to launch a satellite that will broadcast video, radio and data services to portable receivers across Japan and South Korea for mobile users on the go.

Liftoff from pad 36B at Cape Canaveral Air Force Station on Florida's east-central coast is scheduled for Thursday night/Friday morning. The 90-minute launch window extends from 12:41 to 2:11 a.m. EST (0541-0711 GMT).

The weather outlook appears favorable with just a 10 percent chance of showers spoiling the liftoff attempt for this second Atlas launch of 2004.

Powered by a Russian-made RD-180 first stage engine and a single Pratt & Whitney RL10 Centaur upper stage powerplant, the Atlas 3A rocket will propel the Mobile Broadcasting Satellite into geosynchronous transfer orbit during the 29-minute flight.

Called MBSAT for short, the 9,133-pound spacecraft will be released from the rocket in a highly elliptical orbit with an apogee high point between 17,755 and 19,408 nautical miles, a perigee of 98 nautical miles and inclination between 23.43 and 26.6 degrees to the equator.

The rocket's control system is programmed to conduct so-called "in-flight retargeting" of its trajectory based on the vehicle's actual performance and fire the Centaur upper stage until the fuel supply is used up in a procedure called minimum residual shutdown. Those variables are designed to deploy MBSAT into the most optimum orbit possible, and thus the pre-flight orbit predictions have a wide range unlike other launches that target a specific orbit.

The MBSAT spacecraft, built by Space Systems/Loral of Palo Alto, California, will circularize its orbit to geostationary altitude and appear fixed above 144 degrees East longitude to relay MPEG-4 video, CD-quality audio and data to mobile receivers across Japan and South Korea.

According to the designers of this first Digital Multimedia Broadcasting System, programming will be transmitted up to the orbiting MBSAT and then the satellite distributes the video, radio and data offerings to its coverage zone using a large, 40-foot parabolic antenna.

With hand-held and other portable receivers, subscribers can received dozens of music channels, video selections and data-cast services while in driving in cars, riding on trains or sitting in their offices.

Ground-based signal repeaters will fill the satellite reception gaps, which can be created by large buildings blocking the space transmissions.

Mobile Broadcasting Corp. of Tokyo and SK Telecom of Seoul will operate the system.

Friday morning's launch marks the fifth for Lockheed Martin's Atlas 3 rocket fleet since debuting in 2000. Developed as a transitional vehicle between the older Atlas models and next-generation Atlas 5, the Atlas 3 has successfully proved the reliability of the new Russian RD-180 engine and stretched Centaur upper stage used by the Atlas 5 family.

Now, Atlas 3 is being phased out in favor of Atlas 5. The Atlas 3 has just one additional launch scheduled for early next year carrying a classified U.S. National Reconnaissance Office spy satellite payload.

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

MONDAY, MARCH 8, 2004

The early weather projection shows a favorable outlook for Friday's predawn launch of the Atlas 3 rocket from Cape Canaveral. Read the complete weather forecast and the odds for Saturday and Sunday here.