An Ariane 5 rocket, launching for the seventh time this year, lifted off from French Guiana on Wednesday with a secure communications satellite for the British armed forces and an all-purpose broadcasting platform for the Mexican government.

The heavy-lifting launcher blasted off at 2149 GMT (4:49 p.m. EST) from the ELA-3 launch zone at the Guiana Space Center, a European-run spaceport in French Guiana at the edge of the Amazon jungle. Launch occurred at 6:49 p.m. local time.

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In Ariane 5's 67 flights since 1996, the rocket has been successful 63 times.

Jean-Yves Le Gall, Arianespace's chairman and CEO, says this 53rd consecutive success of an Ariane 5 rocket shows "extraordinary reliability." The streak dates back to 2003.

Mexsat Bicentenario separation confirmed. Officials in the Jupiter control room have broken into applause and donned Santa Claus hats in celebration.

Plus+35 minutes. The Sylda adapter has jettisoned, setting the stage for separation of Mexsat Bicentenario at Plus +36 minutes, 11 seconds.

Plus+30 minutes. Separation of the Sylda 5 dual-payload adapter is expected at Plus+34 minutes, 37 seconds to reveal the Mexsat Bicentenario satellite for deployment.

The Skynet 5D communications satellite has separated on schedule, beginning a 15-year mission for Astrium Services and the UK Ministry of Defence.

Plus+25 minutes, 15 seconds. The rocket's second stage shut down as scheduled.

Plus+22 minutes, 30 seconds. The rocket is surpassing a speed of 20,000 mph.

Plus+21 minutes. The upper stage will shut down at Plus+25 minutes, 7 seconds, after reaching a target orbit with a low point of 155 miles, a high point of 22,355 miles, and an inclination of 2 degrees.

Plus+18 minutes. The cryogenic HM7B engine continues to functional well.

Plus+15 minutes. Altitude is 170 km and velocity is 7.66 km/s. In this phase of the launch, the Ariane 5 rocket is intentionally losing altitude to gain velocity.

Plus+12 minutes. This upper stage engine burn will last nearly 16 minutes.

Plus+9 minutes, 25 seconds. The main cryogenic stage's Vulcain engine has cut off and the spent stage has separated. It will fall back into the atmosphere prior to completing an orbit of Earth.

And the upper stage's HM7B engine is now firing to inject the Skynet 5D and Mexsat Bicentenario satellites into orbit.

Plus+7 minutes. Altitute is 209 km and velocity is 4.31 km/s.

Plus+5 minutes. Altitute is 166 km and velocity is 2.94 km/s.

Plus+3 minutes, 30 seconds. Separation of the rocket's nose cone has been confirmed. The Ariane 5 core stage will continue burning until about Plus+9 minutes into the mission.

Plus+2 minutes, 30 seconds. The solid rocket boosters have been jettisoned from the Ariane 5 rocket's core stage. The liquid-fueled Vulcain 2 main engine continues to fire to propel the vehicle and its satellite payload to space.

Plus+60 seconds. The vehicle is on the proper heading as it rides the power of the twin solid rocket boosters and main stage liquid-fueled engine.

Liftoff of an Ariane 5 rocket, lifting payloads to serve the British armed forces and the Mexican government.

Minus-1 minute. A fast-paced series of events leading to launch will begin at Minus-37 seconds when the automated ignition sequence is started. The water suppression system at the launch pad will start at Minus-30 seconds. At Minus-22 seconds, overall control will be given to the onboard computer. The Vulcain main engine will be readied for ignition with hydrogen chilldown starting at Minus-18 seconds.

The residual hydrogen burn flares will fire beneath the Vulcain engine at Minus-6 seconds to burn away any free hydrogen gas. At Minus-3 seconds, onboard systems take over and the two inertial guidance systems go to flight mode. Vulcain main engine ignition occurs at Minus-0 seconds with checkout between Plus+4 and 7 seconds. If there are no problems found, the solid rocket boosters are ignited at Plus+7.0 seconds for liftoff at Plus+7.3 seconds.

Minus-2 minutes. The Vulcain main engine supply valves are being opened. And the ground valves for engine chilldown are being closed.

Minus-3 minutes. The scheduled launch time has been loaded into the rocket's main computer system. The main stage tank pressures should now be at flight level.

Minus-4 minutes. Pressurization is now underway for the main cryogenic stage's liquid oxygen and hydrogen tanks. Also, final pyrotechnic arming is starting.

Minus-5 minutes. All status panel lights remain green, indicating no problems right now that could prevent an on-time blastoff.

Minus-6 minutes. Liquid hydrogen and liquid oxygen supplies of the main cryogenic stage are being verified at flight level. Also, the pyrotechnic line safety barriers are being armed.

Minus-7 minutes and counting. The synchronized sequence has started. Computers are now in control of this automated final phase of the launch countdown to prepare the rocket and ground systems for liftoff. There are three computers running the countdown - one aboard the Ariane 5 and two redundant computers at the launch complex.

Minus-10 minutes. The synchronized launch sequence will begin in three minutes.

Minus-12 minutes. All parameters, including weather and technical readiness, are reporting green on the status board inside the Jupiter control room at the Guiana Space Center.

Minus-20 minutes. The Synchronized Sequence is being prepped for activation. This computer-run sequence assumes control of the countdown at the Minus-7 minute mark to perform the final tasks to place the rocket and pad systems in launch configuration. At Minus-4 seconds, the rocket's onboard computer will take over control of main engine start, health checks of the powerplant and solid rocket booster ignition commanding for liftoff.

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Minus-60 minutes. Arianespace's video coverage is set to begin at 2130 GMT (4:30 p.m. EST). Please refresh this page for a window showing the live webcast.

All parameters continue to look good for launch in one hour. A communications check between ground stations and the rocket should be concluding now.

Minus-2 hours. The Ariane 5's first and second stages are now loaded with cryogenic liquid hydrogen and liquid oxygen propellants.

The fluids are stored at super-cold temperatures and naturally boil off in the warm tropical atmosphere in French Guiana. More propellant is slowly pumped into the rocket for most of the countdown to replenish the cryogenic fuel.

The topping sequence ends in the final few minutes of the countdown as the fuel tanks are pressurized and the fueling system is secured.

With the rocket now fully fueled for launch, the vehicle weighs 1.7 million pounds.

The weather outlook seems promising for an on-time launch at 2149 GMT (4:49 p.m. EST). The launch window extends for 79 minutes to 2308 GMT (6:08 p.m. EST).

Minus-3 hours. The fueling process takes about two hours to fill the Ariane 5's first stage and one hour to load propellant into the cryogenic upper stage.

Chilldown of the first stage Vulcain 2 main engine is scheduled to begin about now in the countdown. This procedure flows super-cold propellant through the engine's fuel lines to condition the hardware for flight.

Check out photos of Ariane 5's rollout to the launch pad yesterday. Th rocket's 1.7-mile journey from the final assembly building to the ELA-3 launch zone was accomplished on dual rails.

With less than four hours remaining in the countdown, fueling of the Ariane 5 rocket's core stage has begun. Cryogenic propellants are now being pumped into two tanks inside the first stage.

Some statistics on today's launch:

• 211th Ariane rocket launch since 1979
• 67th Ariane 5 launch since 1996
• 38th Ariane 5 ECA launch since 2002
• 10th launch from Guiana Space Center this year
• 38th military satellite on Ariane
• 5th Mexican satellite on Ariane

Chilldown of the cryogenic liquid hydrogen and liquid oxygen fueling lines has begun in preparation for filling of the Ariane 5 rocket's two cryogenic stages.

The ground propellant tanks must be pressurized and the fuel lines conditioned for propellant loading before the super-cold fluids are pumped inside the Ariane 5 rocket. Liquid hydrogen and liquid oxygen are stored at minus 423 degrees Fahrenheit and minus 298 degrees Fahrenheit, respectively.

The launch team will load 175 metric tons, or about 385,000 pounds, of propellant into the first stage over the next couple of hours. The second stage tanks will contain about 14.7 metric tons, or about 32,000 pounds, of propellant.

The first stage is powered by a Vulcain 2 engine, and the upper stage features an HM7B engine.

The Ariane 5's large strap-on boosters are each packed with more than 500,000 pounds of solid propellant, generating 90 percent of the rocket's thrust at liftoff.

The launch countdown has begun at the Guiana Space Center for this evening's scheduled liftoff of an Ariane 5 rocket with the Skynet 5D and Mexsat Bicentenario communications satellites.

The weather forecast calls for a moderate chance of lightning, but there is a 79-minute window to get the 166-foot-tall rocket off the ground. The window opens at 2149 GMT (4:49 p.m. EST; 6:49 p.m. local time), about a half-hour after sunset in French Guiana.

Other weather conditions, including upper level winds, are forecast to be acceptable for liftoff today.

An Ariane 5 rocket is positioned on a launch pad in French Guiana for liftoff Wednesday with communications satellites to serve the British military and the Mexican government.

The 166-foot-tall rocket rolled to the Guiana Space Center's ELA 3 launch zone Tuesday, and the booster was connected to ground utilities, including electrical and fueling systems. Workers at the South America launch site planned to fill the Ariane 5's helium pressurant system later Tuesday.

Liftoff of the Ariane 5 rocket is set for 2149 GMT (4:49 p.m. EST; 6:49 p.m. French Guiana time) Wednesday. The launch window extends for 79 minutes.

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