LONDON, October 12, 2011 /PRNewswire/ -- Inmarsat plc (LSE:ISAT.L), the leading provider of global mobile satellite communications services announces that Inmarsat SA, one of its subsidiary companies, has successfully completed Critical Design Review for the Inmarsat-5 satellites, under contract with Boeing. The Inmarsat-5 satellites are a key element of the new Global Xpress™ Ka-band network. "This is a fundamental milestone and marks the transition of the project from a design and engineering phase to a manufacturing, integration and test phase," said Franco Carnevale, Inmarsat vice-president, Space Segment. During the review all aspects of the spacecraft design and operation were thoroughly reviewed by Inmarsat's engineering and operation teams and by a Boeing independent review team. "The review was completed earlier than scheduled, and the conclusion of the CDR board was that the design is mature and there are comfortable margins with all key performance parameters" said Carnevale. Much progress has been made with the manufacturing of key elements of the first spacecraft including structure, propulsion systems and flight hardware such as TWTA. This means the Inmarsat-5 F1 is on schedule for completion and launch in 2013. In parallel, plans for construction of the Proton launch vehicle which will lift Inmarsat-5 into orbit will be discussed at a programmatic kick off meeting with ILS and the vehicle manufacturers Khrunichev in early December. Leo Mondale, Managing Director of Inmarsat Global Xpress, commented: "Our new satellite fleet-build is proceeding at pace and with purpose. We are delighted at Boeing's accelerated milestones and testing performance to date. With Global Xpress we will offer up to 50Mbps to a 60 cm antenna, at highly competitive price points. Inmarsat's Global Xpress is unique in its global Ka-band spot beam coverage with state-of-the-art mobility management. In addition, the service will be supported by multiple steerable beams on each satellite, which will enable us to direct significant capacity, in real time, to the exact location it is needed.