Galaxy XI opens a new era in communications satellites, as the first in Hughes Space and Communications Company's powerhouse HS 702 series. Hughes built the satellite for PanAmSat Corporation to expand video and telecommunications services to North America and Brazil. The satellite was successfully launched on an Ariane rocket from Kourou, French Guiana, on Dec. 21, 1999.

In October 2000, The Boeing Company acquired three units within Hughes Electronics Corporation: Hughes Space and Communications Company, Hughes Electron Dynamics, and Spectrolab, Inc., in addition to Hughes Electronics' interest in HRL, the company's primary research laboratory. The four are now part of Boeing's newest subsidiary, Boeing Satellite Systems, Inc.

The 20-watt C-band transponders will be used primarily for cable television customers. The Ku-band payload offers two power levels: 140 watts for video distribution, and 75 watts for data networks and other general communications services. This gives Galaxy XI a total payload of 64 active transponders, for much greater capacity than the largest satellites now in its fleet.

The Boeing 702 design offers satellite operators a giant in size, performance and cost efficiency. The model was introduced in October 1995, as an evolution of its popular, proven Hughes 601 and Hughes 601HP (high-power) spacecraft. The body-stabilized Boeing 702 can deliver payloads exceeding 90 active transponders, in any communications frequencies that customers request. Power levels start at 10 kilowatts and climb to 15 kilowatts in the "max power" configuration. The spacecraft is adaptable to medium and geosynchronous earth orbits.

Standard on the Boeing 702 is the advanced xenon ion propulsion system (XIPS) that Hughes pioneered. XIPS is 10 times more efficient than conventional liquid bipropellant fuel systems. Four 25-cm thrusters provide economical attitude control, needing only 5 kg of fuel per year ? a fraction of what bipropellant or arcjet systems consume. Customers can apply the weight savings to increase the revenue-generating payload, to prolong service life or to use to a less expensive launch vehicle, when cost is based on satellite weight.

Stowed (left); In Orbit (right)

As a new feature on the Boeing 702, angled reflector panels along both sides of the solar wings form a shallow trough and concentrate the sun's rays on the solar cells. These high-efficiency, dual-junction gallium arsenide cells supply twice the power of traditional silicon cells.

Separating the bus and payload thermal environments and substantially enlarging the heat radiators achieves a cooler, more stable thermal environment for both bus and payload. This increases unit reliability. The deployable radiators use flexible heat pipes, which increase the packageable radiator area.

PanAmSat is the world's leading commercial provider of satellite-based communications services. The company operates a global network of 20 satellites supported by PanAmSat professionals on five continents. These resources enable PanAmSat to provide video and telecommunications services to hundreds of customers worldwide.

Boeing Satellite Systems is the leading manufacturer of commercial communications satellites, and is also a major supplier of spacecraft and equipment to the U.S. government, and builder of weather satellites for the United States and Japan.

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