Arianespace successfully placed a further two commercial satellites into geostationary transfer orbit today.
After an on-time lift-off from Europe’s Spaceport in French Guiana, the Ariane 5 launch vehicle went on to deploy DIRECTV 9S for U.S. digital TV service provider DIRECTV, along with the Optus D1 telecommunications spacecraft for Australia’s Optus.
The launch occurred at 5:56 p.m. local time, providing a rare daytime view of the Ariane 5’s ascent, since most missions occur after sunset. As it climbed into clear skies, the vehicle’s trajectory was followed downrange by tracking cameras, providing an excellent view of its progress – including the jettison of its solid propellant boosters.
Ariane 5 once again demonstrated its excellent accuracy. Provisional parameters at the injection of its ESC-A cryogenic upper stage were:
> Perigee: 249.4 km for a target of 249.5 km (±3)
> Apogee: 35,940 km for a target of 35,946 km (±160)
> Inclination: 6.98 º for a target of 7.0 degrees (±0.06º)
It was Arianespace’s fourth dual-satellite Ariane 5 mission this year, bringing the total payload mass delivered by the workhorse launcher so far in 2006 to more than 31,670 kg. Overall, Ariane vehicles have orbited a combined total payload mass of over 600 metric tons.
DIRECTV 9S weighed approximately 5,535 kg., for today’s mission. It was the sixth satellite to be launched by Arianespace for DIRECTV, Inc., the leading provider of digital multi-channel television service in the United States. The broadcast platform was built by U.S. satellite manufacturer Space Systems/Loral in Palo Alto, California.
Optus D1 was released as the second payload in Ariane 5’s mission sequence. This 2,350 kg. spacecraft is to provide fixed communications and broadcasting satellite services over Australia and New Zealand for Australia’s Optus. The satellite was built by Orbital Sciences Corporation in Dulles, Virginia, and is based on the company’s successful STAR series of smaller-sized spacecraft.
Riding as a piggyback payload on the mission was Japan’s LDREX-2, which is designed to validate the deployment process for a large, lightweight antenna reflector that will be used on Japan’s ETS-8 engineering test satellite. Mounted to the base of Ariane 5’s payload "stack," LDREX-2 was to be commanded through its unfurling sequence after the release of DIRECTV 9S and Optus D1.