BY JUSTIN RAY

Follow the launch of Arianespace's Ariane 5 rocket carrying the JCSAT 10 and Syracuse 3B communications spacecraft. Reload this page for the latest on the mission.

FRIDAY, AUGUST 11, 2006

A heavy-lifting Ariane 5 rocket gave two communications satellites a smooth ride into space Friday in a launch originating from a European-run spaceport nestled in the South American jungle. Read our full story.

2257 GMT (6:57 p.m. EDT)

This was the third of perhaps six Ariane 5 flights in 2006. Next up will be mid-September liftoff of the American DirecTV 9S and Australian Optus D1 communications satellites aboard another Ariane 5 ECA rocket.

"Tonight's success is particularly exemplary, and perfectly illustrates why we have launched a total of 237 satellites during the past 26 years, which, by far, is a world record," said Arianespace Chief Executive Officer Jean-Yves Le Gall.

2250 GMT (6:50 p.m. EDT)

This marks the 25th successful launch of the Ariane 5 rocket and the 14th in a row.

2247 GMT (6:47 p.m. EDT)

Plus+32 minutes, 43 seconds. SPACECRAFT SEPARATION! The French military's Syracuse 3B communications satellite has been released from the Ariane 5 rocket's upper stage, completing today's launch.

Built by Alcatel Alenia Space, this Spacebus 4000 B3-model satellite carries 9 super-high frequency and 6 extremely-high frequency channels to serve military forces across Europe and the Atlantic region. It will be operated at the 5 degree West slot in geostationary orbit.

2245 GMT (6:45 p.m. EDT)

Plus+30 minutes, 40 seconds. The the barrel-like "Sylda" payload adapter between JCSAT 10 and the Syracuse 3B satellite has been jettisoned.

2242 GMT (6:42 p.m. EDT)

Plus+27 minutes, 7 seconds. SPACECRAFT SEPARATION! The Japanese JCSAT 10 spacecraft, weighing 4,048 kg, has been released from the Ariane 5 rocket's upper stage.

Built by Lockheed Martin, this A2100AX-model satellite carries 30 Ku-band and 12 C-band transponders to provide telecommunications across Japan and the Asia-Pacific region. It will be operated by JSAT Corp. to replace the aging JCSAT 3 spacecraft at the 128 degree East slot in geostationary orbit.

2241 GMT (6:41 p.m. EDT)

Plus+26 minutes, 45 seconds. Altitude is 826 km, velocity is 9.2 km/sec.

2239 GMT (6:39 p.m. EDT)

Plus+24 minutes, 42 seconds. The new 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.

2239 GMT (6:39 p.m. EDT)

Plus+24 minutes. Altitude is 478 km, velocity is 9.36 km/sec.

2238 GMT (6:38 p.m. EDT)

Plus+23 minutes. Less than two minutes of propulsion remains in the upper stage. Altitude is 389 km, velocity is 9.19 km/sec.

2237 GMT (6:37 p.m. EDT)

Plus+22 minutes. Altitude is 315 km, velocity is 9.0 km/sec.

2236 GMT (6:36 p.m. EDT)

Plus+21 minutes, 30 seconds. Altitude is 287 km, velocity is 8.9 km/sec.

2235 GMT (6:35 p.m. EDT)

Plus+20 minutes. Just under five minutes remain in this firing of the upper stage. Altitude is 220 km, velocity is 8.6 km/sec.

2234 GMT (6:34 p.m. EDT)

Plus+19 minutes. Altitude is 191 km, velocity is 8.4 km/sec.

2233 GMT (6:33 p.m. EDT)

Plus+18 minutes, 30 seconds. Altitude is 180 km, velocity is 8.4 km/sec.

2232 GMT (6:32 p.m. EDT)

Plus+17 minutes, 15 seconds. Altitude is 163 km, velocity is 8.19 km/sec.

2231 GMT (6:31 p.m. EDT)

Plus+16 minutes. The vehicle is beginning its upward climb again. Altitude is 156 km, velocity is 7.9 km/sec.

2229 GMT (6:29 p.m. EDT)

Plus+14 minutes, 30 seconds. Trajectory and onboard systems remain normal. Altitude is 155 km, velocity is 7.7 km/sec.

2227 GMT (6:27 p.m. EDT)

Plus+12 minutes. Altitude is 162 km, velocity is 7.31 km/sec.

2226 GMT (6:26 p.m. EDT)

Plus+11 minutes. Altitude is 166 km, velocity is 7.16 km/sec.

2225 GMT (6:25 p.m. EDT)

Plus+10 minutes. Altitude is 167 km, velocity is 7.0 km/sec.

2224 GMT (6:24 p.m. EDT)

Plus+9 minutes, 6 seconds. The upper stage of the Ariane 5 ECA rocket has ignited. The cryogenic rocket motor is up and burning.

2224 GMT (6:24 p.m. EDT)

Plus+9 minutes. 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.

2223 GMT (6:23 p.m. EDT)

Plus+8 minutes. Coming up on main stage shutdown in about a minute. Altitude is 166 km, velocity is 5.6 km/sec.

2222 GMT (6:22 p.m. EDT)

Plus+7 minutes. Altitude is 168 km, velocity is 4.5 km/sec.

2221 GMT (6:21 p.m. EDT)

Plus+6 minutes. The rocket's climb has leveled out as designed. This temporary trajectory is needed in order to gain speed. Altitude is 165 km, velocity is 3.7 km/sec.

2220 GMT (6:20 p.m. EDT)

Plus+5 minutes. The main stage's Vulcain 2 engine continues to fire as it burns a mixture of liquid hydrogen and liquid oxygen rocket fuel.

2219 GMT (6:19 p.m. EDT)

Plus+4 minutes, 30 seconds. The rocket is tracking along the proper trajectory.

2219 GMT (6:19 p.m. EDT)

Plus+4 minutes. Ariane 5 is 133 km in altitude and traveling at 2.5 km/sec. All systems are reported normal.

2218 GMT (6:18 p.m. EDT)

Plus+3 minutes, 26 seconds. Arianespace says the protective payload fairing enclosing the payload has been separated from the Ariane 5.

2218 GMT (6:18 p.m. EDT)

Plus+3 minutes. Ariane 5 is 98 km in altitude and traveling at 2.1 km/sec. All systems are reported normal.

2217 GMT (6:17 p.m. EDT)

Plus+2 minutes, 23 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.

2217 GMT (6:17 p.m. EDT)

Plus+2 minutes. A beautiful and on-time liftoff for Ariane 5.

2216 GMT (6:16 p.m. EDT)

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

2216 GMT (6:16 p.m. EDT)

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

2215 GMT (6:15 p.m. EDT)

Plus+35 seconds. Pitch and roll maneuvers has been performed by the Ariane 5 vehicle to position itself on the correct eastward heading bound for geosynchronous transfer orbit.

2215 GMT (6:15 p.m. EDT)

LIFTOFF! Liftoff of the Arianespace Ariane 5 ECA rocket launching Japanese and French communications spacecraft. And the vehicle has cleared the tower!

2214 GMT (6:14 p.m. EDT)

Minus-50 seconds. The vehicle is switching to internal power.

2214 GMT (6:14 p.m. EDT)

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 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.

2213 GMT (6:13 p.m. EDT)

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

2212 GMT (6:12 p.m. EDT)

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.

2211 GMT (6:11 p.m. EDT)

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

2209 GMT (6:09 p.m. EDT)

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

2208 GMT (6:08 p.m. EDT)

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.

2203 GMT (6:03 p.m. EDT)

Minus-12 minutes and counting. All systems remain "go" for launch.

2157 GMT (5:57 p.m. EDT)

Minus-18 minutes and counting. The Ariane 5 rocket is all fueled up with super-cold liquid hydrogen and liquid oxygen propellants. The countdown is headed to the Synchronized Sequence that assumes control of the clock in the final seven minutes to launch. Liftoff remains set for 2215 GMT.

The Arianespace booster will carry the Japanese JCSAT 10 and French Syracuse 3B communications satellites into geosynchronous transfer orbit from the Guiana Space Center on the northeastern shore of South America.

The launch window extends from 2352 GMT (7:52 p.m. EDT).

This will be the third Ariane 5 of 2006, and the vehicle will fly in the more-powerful configuration of the heavy-lift rocket family with the Vulcain 2 upgraded first stage main engine and the ECA cryogenic upper stage.

The final countdown began this morning at the Launch-Minus 11 hour, 30 minute mark. That was followed by a check of electrical systems. Fueling of the first stage and new cryogenic upper stage with super-cold load of liquid hydrogen and liquid oxygen is set to commence in the final five hours before liftoff time.

The countdown will enter the synchronized launch sequence about seven minutes prior to launch. Next will be a fast-paced series of automated events transitioning the rocket and payload to internal power, pressurizing fuel tanks, and taking systems to flight mode. The Vulcain engine will come to life, followed by ignition of the solid rocket boosters and liftoff.

The twin boosters will separate at 2 minutes, 20 seconds, and the payload fairing will be released at Plus+3 minutes, 12 seconds. The cryogenic first stage will exhaust its propellant supply at Plus+8 minutes, 55 seconds, followed six seconds later by the jettisoning. After separation, the cryo upper stage will ignite to begin its 15.5-minute burn to complete the Ariane 5's ascent, shutting down at Plus+24 minutes, 46 seconds.

JCSAT 10 deployment is set for 27 minutes into the mission. Syracuse 3B will be released at Plus+32 minutes, 50 seconds.

Watch this page for live updates during the launch.