The ICO F-1 satellite is shown prior to shipping from the Hughes Space and Communications Co. factory for launch. It stands about 16 feet tall. Photo: Hughes

Two innovative technologies for mobile communications will debut on the ICO F-1 satellite, built by Hughes Space and Communications Co. (HSC) and scheduled for launch Sunday.

Hughes has modified its popular HS 601 spacecraft to build a network of 12 medium-earth-orbit satellites for ICO Global Communications. The first satellite is set for launch at 6:49 a.m. PST Sunday (3/12/00) by Sea Launch, from a platform in the middle of the Pacific Ocean.

The satellites use a unique active phased-array antenna design and a state-of-the-art, digital beam-forming processor developed by HSC.

"The digital signal processor is an incredible invention -- it has more computing power than 600 Pentium III-based computers," said Tig H. Krekel, HSC President and Chief Executive Officer.

"Our dedicated team worked many long hours to develop it over three and a half years. It's 300 times more capable than any previous digital payload launched by Hughes."

The ICO satellites are about 25 percent taller than typical HS 601s, bringing the new design to roughly 16 feet high (5 meters) to accommodate the innovative transmit and receive antennas. These S-band active direct radiating arrays are the direct air link to users. They form multiple beams for high-gain performance and, with multiple satellites in orbit, provide full earth coverage.

The antennas are driven by the digital beam-forming processor. This "smart" processor, designed in the mid-1990s, is the most complex and capable ever flown on a commercial satellite.

The processor constantly changes the beam configuration to match fluctuating usage patterns and make the most efficient use of the bandwidth available. This gives ICO unprecedented flexibility to meet ever-changing market demands.

HSC is responsible for the space segment of the ICO project. This includes not only the manufacture of and launch services for 12 three-ton satellites (10 active and 2 spares), but also for the ground systems that operate the spacecraft from six access nodes around the world and the main ICO control center outside London.

The first ICO satellite is enclosed inside the protective payload fairing. Photo: Sea Launch

HSC built a backup satellite control center at its own facilities near Los Angeles International Airport. Controllers there will fly the ICO F-1 satellite after it separates from Sea Launch's Zenit rocket Sunday, and conduct about a month of in-orbit testing before handing the satellite over to ICO's control. The system will have five operating satellites and a spare in each of two intersecting orbits to provide worldwide coverage.

Besides modifying the height of the HS 601 satellite to accommodate the innovative ICO antennas, HSC extended the thermal radiators to better dissipate the heat created by the high-power electronics. The two solar wings with dual-junction gallium-arsenide solar cells -- built by Spectrolab Inc. -- provide nearly 9 kilowatts of end-of-life power.

The satellites carry a simplified propulsion system because the launch vehicles inject them directly into their operating altitude of 6,456 miles (10,390 km), inclined 45 degrees to the equator. The satellites have an expected life span of 12 years.

HSC and Spectrolab are units of Hughes Electronics Corp. HSC is the world's leading manufacturer of commercial communications satellites. HSC also supplies spacecraft for communications and space exploration to the U.S. government, and builds weather satellites for the United States and Japan. Hughes Electronics is the world's leading provider of digital television entertainment, satellite services and satellite-based private business networks.

The earnings of Hughes Electronics, a unit of General Motors Corp., are used to calculate the earnings per share attributable to the General Motors Class H common stock (NYSE:GMH).