Mission controllers cleared the rocket for launch Thursday during the mission's readiness review, which validated the status of the Ariane 5 ECA and its two spacecraft passengers, along with the infrastructure at Europe's Spaceport in French Guyana and the network of down-range tracking stations.

With the review's successful completion, the launch campaign has now moved into its final phase, Arianespace said in a statement Thursday. Ariane 5 will be rolled out Friday from the Final Assembly Building at Europe's Spaceport, and transferred to the launch zone. On May 27, the final countdown will include a last series of electrical system checks, followed by the main cryogenic stage's fueling with liquid oxygen and liquid hydrogen.

Liftoff is set at the start of a 45-minute launch window that opens at 6:09 p.m. local time. The combined liftoff mass of the Thaicom 5 and Satmex 6 satellites is about 8,500 kilograms (18,750 pounds), which will mark a new launch vehicle performance record to geostationary transfer orbit.

Thaicom 5 - which is the smaller of the mission's two passengers with a liftoff mass targeted at about 2,800 kilograms - carries a mixed payload of 14 Ku-band transponders and 25 C-band transponders. This Alcatel Alenia Space-built relay platform will join the telecom satellite fleet of Thailand's Shin Satellite Public Company Limited, and is to be located at an orbital position of 78.5 degrees east longitude.

Satmex 6 has a mass at liftoff of approximately 5,700 kilograms, and is to be utilized by Mexico's Satelites Mexicanos, S.A. de C.V. to provide coverage over the Continental United States, Mexico and South America. Produced by Space Systems/Loral, Satmex 6 carries 36 C-band and 24 Ku-band transponders, and will operate from an orbital slot of 113 degrees west.

Related Links
Arianespace