HUGHES SPACE AND COMMUNICATIONS COMPANY Communications and Customer Relations P.O. Box 92919 (S10/S323) Los Angeles, CA 90009 Media Relations (310) 364-6363 Investor Relations (310) 662-9688 www.hughespace.com

Hughes is responsible for supplying the MDR communications and crosslink payloads on Milstar. The MDR payload dynamically sorts incoming data and routes them to the proper downlinks to establish networks and provide bandwidth on demand. If necessary it crosslinks the data between satellites.

The current payloads undergoing test are for the F-5 spacecraft, scheduled for launch in 2000. After conducting a series of thermal-vacuum and antenna range tests, HSC integrated antennas and electronic units onto the MDR structure, called the -X (minus X) wing. Final wing-level testing is under way. The wing is scheduled for delivery by May 1999 to prime contractor Lockheed Martin Missiles and Space Company (LMMS). HSC delivered the F-4 -X wing in June 1998, with launch of the F-4 spacecraft set for late 1999.

The F-5 wing will be HSC's third MDR payload and the fifth crosslink payload delivered to LMMS. HSC subcontracts with TRW for the MDR antennas and digital subsystem. LMMS is responsible for the space and mission control segments of the Milstar program.

"HSC is proud to have been part of the Milstar satellite team since 1982," said Tig H. Krekel, president and chief executive officer. "With the launch of F-1 and F-2 in 1994 and 1995, respectively, Milstar became the world's first communications satellite constellation to employ crosslinks." These crosslinks provide rapid, ultra-secure communications by enabling the satellites to pass signals to one another without assistance from ground stations.

The MDR payload uses a 32-channel extremely high-frequency (44 GHz) uplink and a super-high-frequency (20 GHz) downlink. It sends real-time voice, video and data to military personnel in the field at rates that range from 4.8 Kbps to 1.5 Mbps. That is up to 50 times faster than a common PC modem. The crosslinks provide communications capability at 60 GHz between Milstar satellites for both the MDR payload and the 2.4 Kbps low-data-rate (LDR) communications payload on the satellites.

The MDR antennas consist of eight narrow spot beam antennas: six distributed user coverage antennas (DUCAs), and two narrow spot beams with nulling capabilities, known as nuller antennas. In contrast to commercial communications satellites, whose beams can cover entire continents, Milstar's beams are very narrow, providing less opportunity for enemy detection and penetration. The nuller antennas resist jamming from within their respective coverage areas by changing their gain patterns when a jamming signal is detected.

HSC is a major supplier of state-of-the-art radio frequency, microwave and antenna subsystems on Milstar. In addition to the crosslink payloads on the first two satellites, Hughes provided elements of the LDR payload under subcontract to TRW. The MDR payload was incorporated beginning with the F-3 spacecraft, also called the first Milstar II satellite. F-3 is scheduled for launch in April 1999. The complete Milstar constellation will consist of six geosynchronous satellites.

HSC is the world's leading manufacturer of commercial communications satellites, having built about 40 percent of those geosynchronous satellites in operation. It also is a major supplier of spacecraft and equipment to the U.S. government, and a builder of weather satellites. HSC is a unit of Hughes Electronics Corporation. The earnings of Hughes Electronics are used to calculate the earnings per share attributable to GMH (NYSE symbol) common stock.