Inmarsat-4 (I-4) satellites are among the largest and most sophisticated commercial communication satellites built to date, and are capable of delivering advanced voice and broadband data communications to mobile phone users.
"The ILS joint venture...signed a new contract with Inmarsat plc, a European satellite communications operator, to deliver the Inmarsat-4 F3 satellite on board a Proton-M carrier rocket into orbit," the Federal Space Agency said in a statement.
The third and final satellite in the Inmarsat-4 cluster will be launched from the Baikonur space center in Kazakhstan in March or April 2008.
The first in the series, I-4 F1, was launched in March 2005, and has an orbital slot over the Indian Ocean. The second, I-4 F2, was launched in November 2005, and provides coverage for customers in North and South America.
International Launch Services, is a U.S.-Russian joint venture with exclusive rights for worldwide commercial sales and mission management of satellite launches on Russia's Proton carrier rockets.
The joint venture partners are Space Transport Inc., a privately held corporation based in the British Virgin Islands, the Khrunichev State Research and Production Space Center, and RSC Energia of Moscow.
ILS has conducted over 45 commercial Proton launches since 1996, and has a current portfolio of 22 launches through 2013, worth over a billion dollars.
The Proton vehicle launches both commercial ILS missions and Russian government payloads from the Baikonur space center, which is operated by the Russian space agency under lease from the Republic of Kazakhstan.
ILS successfully put into orbit on July 7 a U.S. telecommunications satellite, DirecTV-10, which has approximately the same weight as the Inmarsat 4-F3, about 6 metric tons.