Galaxy X would have joined PanAmSat's fleet of dual-payload spacecraft serving the United States. It was the first satellite to be carried on the new Boeing Delta III rocket. The launch occurred on August 26, 1998, but the satellite was lost when the Delta III failed. In October 1998, PanAmSat ordered a replacement Hughes 601HP satellite, Galaxy X-R, which was successfully launched in January 2000.

The satellite was a Hughes 601HP body-stabilized model built by Hughes Space and Communications Company in El Segundo, Calif. Galaxy X was to significantly increase PanAmSat's domestic U.S. communications capabilities, delivering analog as well as digital cable TV channels and serving as a major pipeline for satellite-based telecommunications networks in the United States. Located at 123 degrees West longitude, Galaxy X would have provided broadcast and telecommunications service to all 50 states and the Caribbean.

All Hughes 601-now Boeing 601-spacecraft use the same basic bus design, allowing the company to realize efficiencies gained by production volume, tooling investments, and quantity buys. The 601 was introduced in 1987, and it has become the world's best-selling large satellite model, with more than 81 ordered by the third quarter of 2000. The standard HS 601 model, with silicon solar panels, provides up to 4-5 kilowatts. The 601HP version uses gallium arsenide solar panels and other technological advances to provide as much as 10 kilowatts.

Stowed (left); In Orbit (right)

Galaxy X would have had 5.8 kilowatts at beginning of life, with power provided by a combination of solar cells. Each of the two solar wings had three panels of silicon solar cells, plus one panel of single-junction gallium arsenide cells.

The Boeing 601 body is composed of two modules. The first contains the primary bus structure that carries all launch vehicle loads and contains the propulsion subsystem, bus electronics, and battery packs. The second payload module is a structure of honeycomb shelves that hold the communications equipment, electronics, and isothermal heat pipes. Reflectors, antenna feeds, and solar arrays mount directly to the payload module, and antenna configurations can be placed on three faces of the bus. This modular approach allows work to proceed in parallel, thereby shortening the manufacturing schedule and test time.

PanAmSat is the world's leading commercial provider of satellite-based communications services. The company operates a global network of 19 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 world's leading manufacturer of communications satellites. It is also a major supplier of spacecraft for communications and space exploration to the U.S. government, and builds weather satellites for the United States and Japan.