Hughes is using an innovative assembly process to build the ICO satellite series, enabling the transmit and receive antenna modules as well as the forward and return transponder panels to be constructed simultaneously and then integrated with the satellite's bus module.

Last month, the F-1 bus module, which contains attitude control, power, propulsion, thermal control, and telemetry and command subsystems, was tested under conditions simulating in-orbit operations.

The final elements to be integrated on the F-1 are the state-of-the-art digital signal processors. Custom-designed for ICO, they offer greatly increased processing capacity over traditional analog designs and much greater flexibility in the allocation of bandwidth and channels to antenna beams.

The design of the digital signal processors has been verified through testing of flight engineering models. The flight models for ICO F-1 currently are in the advanced integration stage and will be incorporated into the satellite in the next few weeks.

The F-1 spacecraft will undergo a series of mechanical and thermal environmental tests prior to the final launch preparation testing.

Meanwhile, the Atlas IIAS vehicle scheduled for the first ICO launch is undergoing final booster assembly at Lockheed Martin's facility in Denver and is on schedule for shipment to Cape Canaveral in September. The satellite will be shipped in November.

ICO plans to launch a total of 12 satellites, including two in-orbit spares, during a 20-month period ending in mid-2000. Five satellites are scheduled to be carried on Boeing Delta III rockets, also from Cape Canaveral, three on Proton boosters from Baikonur Cosmodrome in Kazakhstan and three on Sea Launch Zenits.

Hughes Space & Communications International is the prime contractor for the ICO space segment. The ICO body-stabilized MEO satellites are enhanced versions of the Hughes HS 601 flight-proven spacecraft, weighing just over 6,000 pounds (2,750 kilograms) at launch.

The operational satellites will orbit at an altitude of 10,390 kilometers -- divided equally between two orthogonal planes, each at 45 degrees to the equator -- to provide complete, overlapping coverage of the earth. Each satellite will carry payloads operating in C-band and S-band to support 4,500 simultaneous telephone calls. The satellites are designed to operate for at least 12 years.

ICO Global Communications was established in January 1995 as a private company to provide global mobile personal communications services by satellite, including digital voice, data, fax and messaging services. It has currently raised more than $2 billion in equity contributions and has 60 investors, comprising telecommunications and technology companies from over 50 markets around the world. ICO will begin full operation in the year 2000.