Thefinal space launch of 2005 powered off the pad Wednesday night when a RussianProton M rocket departed Baikonur Cosmodrome carrying an American satellitebuilt to relay broadband communications to specially equipped jetliners flyingacross the Pacific Ocean.
The mission began at 0228GMT (9:28 p.m. EST) with the roar of the heavy-lift Proton's six main enginespropelling the 200-foot rocket into the predawn skies of Kazakhstan. The launch had been delayed from December 5 because of a problem detected inthe vehicle's control system, forcing the rocket to be returned to itsprocessing facility for replacement of a faulty gyroscope. Wednesday'scountdown hit the target launch time as planned.
Less than 10 minutes intothe flight, the three stages that made up the Proton "core vehicle"had completed their systematic firings and dropped away, leaving the Breeze Mand attached AMERICOM 23 spacecraft on a suborbital trajectory. The upper stagethen performed its first firing into a low-altitude parking orbit roughly 108miles high as the vehicle flew off the eastern-most stretches of Asia.
Four more burns are plannedover nine hours to reach a 4,000 x 22,240 mile deployment orbit for the11,000-pound AMERICOM 23 spacecraft.
This is the seventh Protonmission of the year -- the second sinceSunday -- and the venerable vehicle's 318th flight in four decades. It was thefourth commercial Proton flight performed in 2005 under the control ofInternational Launch Services -- the firm set up to market Proton and AmericanAtlas rockets. ILS has now flown 35 Proton missions over the past 10 years.
AMERICOM 23 will use anonboard kick engine to ascend into geostationary orbit where the spacecraftwill park itself at 172 degrees East longitude along the equator. That vantagepoint will enable the satellite to beam signals northward to Alaska, southwardto Australia and New Zealand and anywhere across the Pacific between California and Bangladesh.
Princeton, New Jersey-basedSES AMERICOM will operate the Spacebus 4000 satellite during its 16-year designlife. The craft was built in Toulouse and Cannes, France by Alcatel AleniaSpace -- the new European firm created by the joining of Alcatel Space andAlenia Spazio.
The Ku-band communicationspayload of 20 high-powered transponders will serve long-haul airline routesover the Pacific to provide broadband connectivity for the Connexion by Boeingsystem. Passengers can use their laptops to check email and access the Internetwith high-speed links.
The 18-transponder C-bandpackage on the satellite will focus on the ground for more conventionaltelecommunications services of television and cable broadcasters, Internetproviders, government and educational customers, and networking links betweenNorth America and the Pacific Rim.
"We compliment theAlcatel Alenia Space team for delivering this very sophisticated satellite,which we designed to address a spectrum of customer applications for the nextdecade and beyond," Ed Horowitz, president and CEO of SES AMERICOM, saidrecently. "We have customers on both sides of the Pacific waiting to useboth payloads in early 2006."
The rocket launchingAMERICOM 23 is the modernized Proton vehicle built by Khrunichev. Russianofficials say the Proton M is friendlier to the environment since its optimizedengines leave less unused fuel in the booster. Any residual propellant is thenvented in the atmosphere before the vehicle stages impact in Kazakhstan, reducing contamination in the landing area.
The rocket also sportsupgraded digital control avionics that improves the accuracy of the launch.
The Breeze M stage, alsomade by Khrunichev, was designed to be relatively compact in size to free upmore space in the rocket's nose cone for the payload. It was derived from theBreeze stage flown on the smaller Rockot vehicle.
The Proton M/Breeze M canhaul heavier payloads into orbit than the older Proton K and Block DM upperstage combination.