BY SPACEFLIGHT NOW

Follow the launch of Arianespace's Ariane 5 rocket carrying the SATMEX 6 and THAICOM 5 communications spacecraft. Reload this page for the latest on the mission.

SATURDAY, MAY 27, 2006
2144 GMT (5:44 p.m. EDT)

Arianespace has set a record by launching over 8 metric tonnes into geosynchronous transfer orbit -- the combined weight of SATMEX 6 and THAICOM 5. Chief executive officer Jean-Yves Le Gall confirms the launch has been a success, completing the second Ariane 5 flight of 2006. Four more launches are expected this year.

2141 GMT (5:41 p.m. EDT)

Plus+32 minutes, 17 seconds. SPACECRAFT SEPARATION! The THAICOM 5 communications satellite for Thailand has been released from the Ariane 5 rocket's upper stage, completing today's launch.

2139 GMT (5:39 p.m. EDT)

Plus+30 minutes, 30 seconds. Altitude is 1,590 km, velocity is 8.6 km/sec.

2138 GMT (5:38 p.m. EDT)

Plus+29 minutes, 55 seconds. The the barrel-like "Sylda" payload adapter between SATMEX 6 and the THAICOM 5 satellite has been jettisoned.

2136 GMT (5:36 p.m. EDT)

Plus+27 minutes, 2 seconds. SPACECRAFT SEPARATION! The Mexican SATMEX 6 spacecraft has been released from the Ariane 5 rocket's upper stage.

2136 GMT (5:36 p.m. EDT)

Plus+27 minutes. Altitude is 939 km, velocity is 9.1 km/sec.

2135 GMT (5:35 p.m. EDT)

Plus+26 minutes. Altitude is 785 km, velocity is 9.2 km/sec.

2133 GMT (5:33 p.m. EDT)

Plus+24 minutes, 53 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.

2133 GMT (5:33 p.m. EDT)

Plus+24 minutes. Altitude is 528 km, velocity is 9.2 km/sec.

2132 GMT (5:32 p.m. EDT)

Plus+23 minutes. Less than two minutes of propulsion remains in the upper stage. Altitude is 430 km, velocity is 9.1 km/sec.

2131 GMT (5:31 p.m. EDT)

Plus+22 minutes. Altitude is 351 km, velocity is 8.9 km/sec.

2130 GMT (5:30 p.m. EDT)

Plus+21 minutes. Altitude is 289 km, velocity is 8.7 km/sec.

2129 GMT (5:29 p.m. EDT)

Plus+20 minutes. Just under five minutes remain in this firing of the upper stage. Altitude is 241 km, velocity is 8.6 km/sec.

2128 GMT (5:28 p.m. EDT)

Plus+19 minutes. Altitude is 206 km, velocity is 8.4 km/sec.

2127 GMT (5:27 p.m. EDT)

Plus+18 minutes. No problems have been reported during the flight. Altitude is 182 km, velocity is 8.2 km/sec.

2126 GMT (5:26 p.m. EDT)

Plus+17 minutes. Altitude is 167 km, velocity is 8.1 km/sec.

2125 GMT (5:25 p.m. EDT)

Plus+16 minutes. Altitude is 158 km, velocity is 7.9 km/sec.

2124 GMT (5:24 p.m. EDT)

Plus+15 minutes. The vehicle is beginning its upward climb again. Altitude is 154 km, velocity is 7.79 km/sec.

2123 GMT (5:23 p.m. EDT)

Plus+14 minutes. Altitude is 153.2 km, velocity is 7.62 km/sec.

2121 GMT (5:21 p.m. EDT)

Plus+12 minutes. Altitude is 156 km, velocity is 7.3 km/sec.

2119 GMT (5:19 p.m. EDT)

Plus+10 minutes, 5 seconds. Altitude is 158 km, velocity is 7.0 km/sec.

2118 GMT (5:18 p.m. EDT)

Plus+9 minutes, 19 seconds. The cryogenic upper stage of the Ariane 5 ECA rocket has ignited.

2118 GMT (5:18 p.m. EDT)

Plus+9 minutes, 3 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.

2117 GMT (5:17 p.m. EDT)

Plus+8 minutes. Coming up on main stage shutdown in about a minute. Altitude is 157 km, velocity is 5.5 km/sec.

2116 GMT (5:16 p.m. EDT)

Plus+7 minutes. Altitude is 160 km, velocity is 4.5 km/sec.

2115 GMT (5:15 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 159 km, velocity is 3.7 km/sec.

2114 GMT (5:14 p.m. EDT)

Plus+5 minutes. The main stage continues to fire. Altitude is 149 km, velocity is 3.0 km/sec.

2113 GMT (5:13 p.m. EDT)

Plus+4 minutes. The rocket is tracking along the proper trajectory. Altitude is 129 km, velocity is 2.5 km/sec.

2112 GMT (5:12 p.m. EDT)

Plus+3 minutes, 20 seconds. Arianespace says the protective payload fairing enclosing the payload has been separated from the Ariane 5.

2112 GMT (5:12 p.m. EDT)

Plus+3 minutes. Altitude is 95 km, velocity is 2.1 km/sec. All systems are reported normal.

2111 GMT (5:11 p.m. EDT)

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.

2111 GMT (5:11 p.m. EDT)

Plus+2 minutes. Altitude is 47 km, velocity is 1.8 km/sec.

2110 GMT (5:10 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.

2110 GMT (5:10 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.

2109 GMT (5:09 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, as it punches through cloud cover over the launch site.

2109 GMT (5:09 p.m. EDT)

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

2108 GMT (5:08 p.m. EDT)

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

2108 GMT (5:08 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.

2107 GMT (5:07 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.

2106 GMT (5:06 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.

2105 GMT (5:05 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.

2103 GMT (5:03 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.

2102 GMT (5:02 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.

2055 GMT (4:55 p.m. EDT)

Minus-14 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 2109 GMT.

SATURDAY, MAY 27, 2006

An Arianespace Ariane 5 rocket will launch Mexican and Thai telecommunications satellites today from the Guiana Space Center on the northeastern shore of South America.

The launch window extends from 2109 to 2154 GMT (5:09-5:54 p.m. EDT).

This will be the second 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 rocket is carrying the SATMEX 6 communications spacecraft for Mexico and THAICOM 5 for Thailand.

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, 15 seconds. The cryogenic first stage will exhaust its propellant supply at Plus+8 minutes, 56 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, 51 seconds.

SATMEX 6 deployment is set for 27 minutes into the mission. THAICOM 5 will be released at Plus+32 minutes, 19 seconds.

Watch this page for live updates during the launch.