The next Ariane 5 launch is targeted for mid-December carrying the Skynet 5D military communications satellite for the British Ministry of Defence and Mexsat 3 for communications services to Mexico.

The Ariane 5 rocket has achieved its 52nd consecutive successful launch since 2003 and the vehicle's 62nd overall success in 66 flights since 1996.

Plus+33 minutes, 20 seconds. SPACECRAFT SEPARATION! The Star One C3 communications satellite has been released from the Ariane 5 rocket's upper stage, completing today's launch.

Built by Orbital Sciences using its Star 2.4E design and weighing 7,114 pounds at launch, the spacecraft will join a fleet of geostationary satellites serving South America for Star One S.A. of Rio de Janeiro, Brazil.

It is headed for geostationary orbit a slot of 75 degrees West longitude for a mission exceeding 16 years using 28 C-band and 16 Ku-band transponders for direct-to-home television, broadband internet, long-distance telecommunications services to Brazil, Colombia, Peru, Bolivia and Ecuador.

It replaces the Brasilsat B3 satellite that was launched atop an Ariane 44LP rocket in February 1998 from Kourou.

Plus+31 minutes, 30 seconds. Ariane is 1,820 km in altitude.

Plus+29 minutes, 40 seconds. The barrel-like "Sylda" payload adapter between Eutelsat 21B and the Star One C3 satellites has been jettisoned. This has exposed Star One C3 for its upcoming release from the rocket.

Plus+29 minutes. Ariane is 1,310 km in altitude and coasting higher in its geosynchronous transfer orbit.

Plus+28 minutes, 5 seconds. SPACECRAFT SEPARATION! The Eutelsat 21B spacecraft has been released from the Ariane 5 rocket's upper stage, beginning a planned 15-year life span.

Built by Thales Alenia Space using the Spacebus 4000 C3 satellite design, the craft is equipped with 40 Ku-band transponders to double the transmission capabilities from Eutelsat's geostationary orbital slot of 21.5 degrees East. That position 22,300 miles above Earth covers a swath from Europe to North Africa, the Middle East and into central Asia to provide video relay, government communications, corporate networking, telephone connectivity and rural internet services.

It replaces the Eutelsat 21A satellite, originally known as W3, that was launched atop a Lockheed Martin Atlas 2AS rocket in April 1999 from Cape Canaveral.

The 11,050-pound satellite will be maneuvered from its current geosynchronous transfer orbit in the coming days for use by Eutelsat of Paris. The firm's constellation features 29 satellites going into today's launch operating from 20 orbital positions to beam more than 4,200 television channels and various other telecommunications services to over 150 countries.

Plus+26 minutes. Now orienting the proper attitude for release of Eutelsat 21B. Altitude is 801 km, velocity is 9.2 km/sec.

Plus+24 minutes, 59 seconds. The cryogenic upper stage for Ariane 5 has just shut down to complete its burn for today's launch. The stage will prepare for deployment of the two satellite payloads a few minutes from now.

Plus+24 minutes, 30 seconds. Ariane is 596 km in altitude and traveling at 9.3 km/sec.

Plus+23 minutes, 50 seconds. Ariane is 522 km in altitude and traveling at 9.2 km/sec.

Plus+23 minutes, 15 seconds. Less than two minutes of propulsion remains in the upper stage.

Plus+22 minutes, 30 seconds. Ariane is 399 km in altitude and traveling at 8.99 km/sec.

Plus+21 minutes, 30 seconds. Ariane is 327 km in altitude and traveling at 8.8 km/sec.

Plus+20 minutes, 45 seconds. Ariane is 283 km in altitude and traveling at 8.72 km/sec.

Plus+20 minutes. Just five minutes remain in this firing of the upper stage.

Plus+19 minutes. Ariane is 214 km in altitude and traveling at 8.45 km/sec.

Plus+18 minutes. Ariane is 189 km in altitude and traveling at 8.2 km/sec.

Plus+17 minutes. Ariane is 174 km in altitude and traveling at 8.1 km/sec.

Plus+16 minutes, 30 seconds. The vehicle is on the upward climb again. Ariane is 169 km in altitude and traveling at 8.0 km/sec.

Plus+15 minutes. Altitude is 162 km, velocity is 7.81 km/sec.

Plus+14 minutes. Ariane is 162 km in altitude and traveling at 7.65 km/sec.

Plus+12 minutes, 50 seconds. Ariane is 165 km in altitude and traveling at 7.48 km/sec.

Plus+11 minutes, 50 seconds. Ariane is 169 km in altitude and traveling at 7.33 km/sec.

Plus+11 minutes, 30 seconds. The cryogenic upper stage motor continues to fire as the rocket starts the next portion of the trajectory where it gives up a little bit of altitude to obtain even quicker speeds.

Plus+10 minutes, 55 seconds. Ariane is 173 km in altitude and traveling at 7.2 km/sec.

Plus+10 minutes. Ariane is 176 km in altitude and traveling at 7.0 km/sec.

Plus+9 minutes, 20 seconds. The upper stage of the Ariane 5 ECA rocket is up and burning to accelerate the payload into geosynchronous transfer orbit.

Plus+9 minutes, 2 seconds. The main cryogenic stage's Vulcain engine has cut off and the spent stage has separated. It will fall back into the atmosphere.

Plus+8 minutes, 30 seconds. Ariane is 179 km in altitude and traveling at 6.4 km/sec.

Plus+8 minutes. Coming up on main stage shutdown in about one minute.

Plus+7 minutes, 45 seconds. Ariane is 180.1 km in altitude and traveling at 5.4 km/sec.

Plus+7 minutes, 30 seconds. The rocket's climb has leveled out as designed. This temporary trajectory is needed in order to gain speed.

Plus+7 minutes. Ariane is 179 km in altitude and traveling at 4.5 km/sec.

Plus+6 minutes. The main stage's Vulcain 2 engine continues to fire as it burns a mixture of liquid oxygen and liquid hydrogen rocket fuel.

Plus+5 minutes. Ariane is 156 km in altitude and traveling at 3.0 km/sec.

Plus+4 minutes. Ariane remains right on course. The rocket is 135 km in altitude and traveling at 2.6 km/sec.

Plus+3 minutes, 33 seconds. Separation of the rocket's nose cone has been confirmed, uncovering the Eutelsat 21B satellite in its upper position in the dual payload stack.

Plus+3 minutes. The vehicle is 97 km in altitude, traveling at 2.21 km/sec.

Plus+2 minutes, 22 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+2 minutes. A spectacularly clear early evening ascent by Ariane 5!

Plus+1 minute, 30 seconds. Less than a minute left in the burn by the solid rocket boosters. The boosters are providing 90 percent of the liftoff thrust.

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

Plus+35 seconds. Pitch and roll maneuvers has been performed by the Ariane 5 vehicle to position itself on the correct eastward trajectory bound for its highly elliptical orbit to drop off two telecommunications satellites.

LIFTOFF! Liftoff of the Ariane 5 rocket, providing commercial access to space for Eutelsat 21B and Star One C3. And the vehicle has cleared the tower!

Minus-50 seconds. The vehicle is running on internal power.

Minus-1 minute. Final 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 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 2 main engine supply valves are being opened. And the ground valves for engine chilldown are being closed.

Minus-3 minutes. The upper stage cryogenic tanks are charging to flight pressures. And the scheduled launch time has been loaded into the rocket's main computer system.

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

Minus-5 minutes. Still heading for a launch at the opening of today's window.

Minus-6 minutes and counting. Liquid hydrogen and liquid oxygen supplies of the main and upper cryogenic stages are being topped off at flight levels. Also, the pyrotechnic line safety barriers are being armed.

Minus-7 minutes and counting. The Synchronized Sequence is starting. Computers are now in control of this final segment of the launch countdown to prepare the rocket and ground systems for liftoff. There are two computers running the countdown -- one aboard the Ariane 5 and a redundant one at the ELA-3 launch complex.

Minus-10 minutes and counting. Still all green across the status board in launch control as the countdown heads for the Synchronous Sequence.

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Minus-12 minutes and counting. No launch constraints are being reported with the Ariane rocket, its double satellite payload, ground systems or the weather. The Synchronized Sequence will assume control of the clock at 2058 GMT to govern the final seven minutes to launch.

Minus-15 minutes and counting. Both satellites going up today will be replacing aging spacecraft in their respective operators' constellations. Eutelsat 21B will replace the 21A craft deployed by an Atlas 2AS rocket from Cape Canaveral in April 1999 and Star One C3 takes over the orbital slot of Brasilsat B3 than an Ariane 44LP rocket launched in February 1998.

Minus-20 minutes and counting. Today's mission represents the 66th launch for the Ariane 5 rocket dating back to 1996 and the sixth this year. It is the 210th flight overall for the Ariane family of launchers since 1979.

What's more, it is the 26th Eutelsat spacecraft entrusted to Arianespace over the past quarter-century and the 9th Brazilian satellite to fly on the European launcher since 1985.

Welcome to our live launch coverage of Ariane 5 with the Eutelsat 21B and Star One C3 payloads. Liftoff remains scheduled for 2105 GMT from the Guiana Space Center in Kourou, French Guiana on the northeastern coast of South America.

The Ariane 5 rocket is fully fueled, weather is GO and no technical problems are being reported in the countdown.

The Ariane 5 rocket is being fueled up with supercold liquid hydrogen and liquid oxygen as the countdown ticks for today's launch at 4:05 p.m. EST (2105 GMT). The available launch window remains unchanged from yesterday, lasting 106 minutes to 5:51 p.m. EST (2251 GMT).

SCRUB! Today's launch of the Ariane 5 rocket has been postponed 24 hours to Saturday due to unfavorable high-altitude wind conditions at the Guiana Space Center in Kourou. Officials are expecting better winds aloft for the next shot.

Loaded with a dual payload of satellites for Europe and Brazil, the commercial Ariane 5 rocket today was transported by rail to its launch pad in the equatorial jungles of South America for blastoff on Friday.

Traveling the 1.7-mile trek, the 16-story-tall Ariane 5 was rolled out from its final assembly building where the two payloads had been mounted atop the vehicle.

Friday's liftoff, unleashing 2.6 million pounds of thrust from its hydrogen-fueled main stage and twin solid rocket boosters, is scheduled for 4:05 p.m. EST (2105 GMT). The day's available launch window extends 106 minutes to 5:51 p.m. EST.

Join is for live updates and streaming video of the launch on this page starting about 20 minutes before liftoff time.

Bound for a typical geosynchronous transfer orbit, the rocket will first deploy the Eutelsat 21B craft to provide a range of telecommunications, data relay and Internet capabilities across Europe, the Middle East, Africa and Central Asia, then release the Star One C3 satellite for direct-to-home television and telephone services to Brazil and South America.

The two satellites, plus the dual-payload adapter equipment amount to 20,318 pounds, including 18,188 pounds just for the two spacecraft.

The countdown clock will be started by Arianespace at 4:35 a.m. EST and a complete check of electrical systems occurs at 8:35 a.m. EST.

Fueling of the Ariane 5 with super-cold liquid hydrogen and liquid oxygen propellants begins at 11:15 a.m. EST. First, ground reservoirs will be pressurized, then the fuel lines will be chilled down to condition the plumbing for the flow of super-cold liquid hydrogen and liquid oxygen, which are stored at minus 423 degrees Fahrenheit and minus 298 degrees Fahrenheit, respectively.

It will take approximately two hours to fill the tanks contained within the rocket's main stage.

A similar procedure for the Ariane 5's cryogenic upper stage will commence at 12:15 p.m. EST.

Chilldown conditioning of the Vulcain 2 first stage engine will occur at 12:45 p.m., and a communications check between the rocket and ground telemetry, tracking and command systems is scheduled for 2:55 p.m. EST.

The computer-controlled synchronized countdown sequence will begin seven minutes before launch to pressurize propellant tanks, switch to onboard power and take the rocket's guidance system to flight mode.

The Vulcain 2 main engine ignites as the countdown reaches zero, followed by a health check and lighting the Ariane 5's solid rocket boosters seven seconds later to send the 1.7-million-pound launcher skyward.

Five seconds after blastoff, the rocket will begin pitching east from the ELA-3 launch pad, surpassing the speed of sound less than a minute into the mission. The pair of solid rocket boosters will jettison at T+plus 2 minutes and 22 seconds some 42 miles in altitude.

Once above the dense atmosphere, the launcher's payload fairing will fall away three-and-a-half minutes into flight at an altitude of 72 miles. The Ariane 5's first stage will shut down at T+plus 8 minutes, 51 seconds, followed moments later by stage separation and ignition of the hydrogen-fueled cryogenic HM7B upper stage engine all at altitude of 111 miles.

The rocket's upper stage will fire for nearly 16 minutes, accelerating to a velocity of 20,920 miles per hour to reach an elliptical orbit with an advertised high point of 22,323 miles, a low point of 155 miles and inclination of 2 degrees relative to the equator.

The release of Eutelsat 21B is scheduled for T+plus 28 minutes, 2 seconds. The rocket's barrel-like Sylda 5 dual-payload adapter will be jettisoned 29-and-a-half minutes into the flight to uncover the second passenger.

Star One C3 will separate from the lower portion of the payload stack at T+plus 33 minutes, 17 seconds, capping the ascent.