posted 04-04-2011 03:38 AM               

Ariane 5 launch with Yahsat Y1A and Intelsat New Dawn: Launch countdown interrupted

The launch countdown for tonight's [March 30] Ariane 5 mission with the Yahsat Y1A and Intelsat New Dawn satellites was interrupted prior to liftoff when an anomaly detected during the automated checkout procedure stopped the sequence before ignition of the solid boosters.

The synchronized countdown was conducted as planned, including the startup of Ariane 5's cryogenic main engine. Following the normal procedures for an Ariane 5 launch, this cryogenic engine's operation is fully validated during a period of seven seconds before an ignition command is given to the two solid boosters - which commits the vehicle to liftoff.

Arianespace Chairman & CEO Jean-Yves Le Gall said the cryogenic main engine's checkout process was not completed successfully because of an anomaly detected on the launcher, preventing the boosters' ignition and thereby averting the launch. The Ariane 5 and its two payloads were then switched to a safe mode on the launch pad.

Le Gall stated that while data analysis is underway to determine the anomaly's source, the Ariane 5 will be rolled back to the Spaceport's Final Assembly Building, where it is to be returned to a flight-ready condition. "We do not take any risks, and therefore it is very important we determine the causes," he added.

Arianespace will set a new launch date as soon as possible.

posted 04-23-2011 02:33 PM               

Ariane 5 delivers a record performance with two payloads for new Arianespace customers

A heavy-lift Ariane 5 successfully orbited two satellite payloads today that will supply telecommunications services for two new customers who join the growing list of Arianespace commercial launch services users.

In a flight conducted from the Spaceport in French Guiana, the Ariane 5 deployed Yahsat Y1A, the first satellite to be operated by the United Arab Emirates' Al Yah Satellite Communications Company; along with Intelsat New Dawn, which was built for the new joint venture of Intelsat and Convergence Partners.

Adding to this mission's milestones was the lift performance record for Ariane 5: delivering a total mass of 10,050 kg. to geostationary transfer orbit, of which 8,956 kg. was the combined weight of its two satellite payloads.

Lifting off on time at 6:37 p.m. in French Guiana, the Ariane 5 climbed through a partial cloud cover at sunset, and continued its downrange flight in clear skies. This allowed a direct view of the separation for Ariane 5's two solid propellant boosters at an altitude of 66.5 kilometers, followed by the payload fairing's jettison at a 105-kilometer altitude.

It marked another of Ariane 5's highly accurate flights, with the following estimated orbital parameters at the injection of its cryogenic upper stage:

• Perigee: 249.8 km. for a target of 249.7 km.
  
• Apogee: 35,975 km. for a target of 35,956 km.
  
• Inclination: 5.98 deg. for a target of 6.00 deg.

For tonight's mission, Yahsat Y1A was positioned in the upper passenger slot of Ariane 5's dual-payload "stack," and was released at 27 minutes into the flight. This spacecraft was built by Astrium based on the Eurostar E3000 platform, while its Ku-band and C-band communications payload was supplied by Thales Alenia Space.

Yahsat Y1A will have a coverage footprint spanning the Middle East, Africa, and Southwest Asia, creating regionally-focused capacity to meet the region's expanding requirements for government, commercial and consumer satellite communication services. Operating from an orbital slot of 52.5 deg. East, it will support Abu Dhabi's ambition to become a hub for media broadcasting and telecommunications services - enabling customers from Europe and South Asia to connect with customers across the entire coverage area.

Intelsat New Dawn - which was deployed from Ariane 5's lower payload position at 35 minutes into tonight's flight - is owned by a joint venture of Intelsat and a consortium led by Convergence Partners. This satellite's C-band and Ku-band transponders are to support the communications infrastructure for African customers who have experienced exceptional growth, and contribute to the region's development. It is tailored for voice, wireless backhaul, Internet and media applications services.

Built by Orbital Sciences Corporation using its STAR-2 platform, Intelsat New Dawn will be integrated with Intelsat's global satellite fleet and stationed at the 32.8 deg. East orbital location. It was the 52nd satellite launched by Arianespace for Intelsat, the world's leading satellite operator.

Following today's successful mission, Arianespace Chairman & CEO Jean-Yves Le Gall announced the date for its next Ariane 5 launch: a May 19 liftoff from the Spaceport with the ST-2 payload for ST-2 Satellite Ventures Pte Ltd., and the GSAT-8 spacecraft for the Indian Space Research Organisation.