At 17:07 Moscow Time (14:07 GMT) Zenit-3SL Integrated Launch Vehicle (ILV) carrying Inmarsat-4 Spacecraft (SC) as a payload was launched from the sea-going Launch Platform (LP) Odyssey as part of the Sea Launch Rocket and Space Complex.

During the launch the LP was floating in equatorial area of the Pacific Ocean, in the vicinity of Christmas Island (154° W).

The objective of the launch is to deliver a 6-ton spacecraft (SC) to a target geosynchronous transfer orbit. Upper Stage (US) Block DM-SL produced at RSC Energia after S.P. Korolev made it possible to put the SC into this orbit from an intermediate orbit formed by Zenit-2S two-stage launch vehicle (LV).

The US Block DM-SL provided a highly accurate delivery of SC to a target geosynchronous transfer orbit with the following design parameters: inclination – 3°; perigee altitude – 310 km; apogee altitude –35786 km.

There were two burns of the US Main Engine under the Mission Program. The first burn lasting about 4.5 seconds was performed following 10 seconds upon separation of the US mated with SC from the LV 2nd stage. The second burn lasting some 7 min. occurred following 55 min. after completion of the first burn.

At 18:32 Moscow Time SC separated from the Upper Stage.

This was the 253rd successful mission of the Upper Stage DM (D) and the fifth mission since the beginning of 2005.

Following its autonomous transfer to the given orbital position in geostationary orbit (53° W), the SC will be made a part of global satellite broadband communication network offering a wide range of mobile telecommunication services (access to Internet, facsimile and telephone communication, transmission of video images at subscribers’ requests, videoconferencing, etc.).

Inmarsat-4 is the first Inmarsat SC inserted into near-earth orbit from the Sea Launch Rocket and Space Complex, which is also the first European Spacecraft launched by means of the launch services provided by international joint stock Sea Launch Company. The satellite was manufactured by “EADS Astrium” under the Inmarsat order.

Sea Launch has the following shareholders: the Boeing Company (USA), Rocket and Space Corporation Energia after S.P. Korolev (Russia), “Kvaerner Invest Norge AS” (Norway) and the Ukrainian aerospace enterprises Production Association Yuzhmash zavod and State Design Office Yuzhnoye after M.K. Yangel. RSC Energia is the prime enterprise for the Sea Launch Complex Rocket Segment. It is responsible for its outfitting and integration into the Complex ensuring along with other subcontracting industrial enterprises US Block DM-SL manufacture and operational use as the 3rd Stage of Zenit-3SL ILV.

Prelaunch processing and launch operations were controlled from the Control Center aboard the Sea Launch Commander Assembly – Command Ship (ACS). The prelaunch operations initiated 6 hours prior to the launch were performed in an automatic mode. 3 hours before the launch, the LP Odyssey’s crew and the LP-based personnel in ILV prelaunch processing had been evacuated by helicopter to the ACS taken away at a safe distance from the LP.

The prelaunch processing and launch operations were conducted under the direction of Sea Launch Company’s Mission Director Mr. D. Dubbs and the Rocket Segment Operations Manager RCS Energia’s Deputy Designer General V.G. Aliev.

Analysis of the mated US/SC flight was performed by RSC Energia’s specialists included in the Lead Operations Control Team (LOCT) based in the Mission Control Center (MCC-M), the city of Korolev, Moscow Region and maintaining continuous communication with the ACS-based Control Center. The LOCT Manager is V.A. Solovyov, RSC Energia’s Vice-President, Deputy Designer General. In support of the Upper Stage–downlinked telemetry data analysis, both American and Russian space data receiving/transmission facilities were used.

Upon the SC separation from the Upper Stage, RSC Energia’s President, Designer General N.N. Sevastiyanov working in the MCC-M mission control room telephoned congratulations on the successful launch to V.G. Aliev, the Rocket Segment Operations Manager, the team of RSC Energia’s specialists directly involved in ILV prelaunch processing and launch at the sea-going cosmodrome, all ACS and LP personnel as a whole.

That was the fourth launch in 2005 under the Sea Launch Program and the 18th launch under the common list of the performed launches within this program.

The next launch from the sea-based Sea Launch Rocket and Space Complex is slated for January 2006.