Spaceflight Now: Breaking News

Hughes satellite will launch technology to new era
Galaxy 11 is first powerhouse HS 702
Posted: Dec. 15, 1999

  Galaxy 11
Galaxy 11, the world's largest commercial communications satellite and the first HS 702 to be built, during final preparations. Photo: Hughes
Hughes Space and Communications Company (HSC) will open a new era in communications satellites with this month's launch of Galaxy 11, the company's first HS 702 satellite, built for PanAmSat Corp.

Galaxy 11, with a total of 64 transponders and end-of-life power of more than 10 kW, will be the largest commercial communications satellite ever deployed into space.

The 10-minute Ariane 4 launch window at the Guiana Space Center opens at 9:50 p.m. (4:50 p.m. PST, Dec. 21, 12:50 a.m. GMT, Dec. 22).

"The launch of Galaxy 11 is a major event for PanAmSat and Hughes as well as the entire satellite communications industry, as we deploy this powerful new satellite," said R. Douglas Kahn, PanAmSat's president and chief executive officer. "The HS 702-model Galaxy 11, with its large communications payload and high power, represents exciting new satellite technology from HSC. Galaxy 11 will enable PanAmSat to deliver state-of-the-art satellite services to video, Internet and telecommunications customers throughout North America."

"Hughes has anticipated this launch with great excitement, for it reaffirms Hughes as the world's premier supplier of the most capable and powerful satellites available anywhere," said Tig H. Krekel, president and chief executive officer of HSC. "And we won't stop with the HS 702. Recognizing our customers' growing requirements, we are currently developing even more powerful satellites. But Galaxy 11 is clearly a milestone launch for us, and I congratulate PanAmSat and the employees of Hughes on this stellar achievement."

Galaxy 11 is the first of seven new satellites that Hughes is manufacturing for PanAmSat, and will provide video distribution, telephony and data services to North America and Brazil from an orbital position of 99 degrees West longitude, before being migrated to 91 degrees West at a later date. The remaining six spacecraft are scheduled for launch by mid-2001. Galaxy 11 will carry 40 Ku-band and 24 C-band transponders and will provide more than 15 years of service.

"The HS 702 leverages many of the efficiency-producing technologies inherent in Hughes' other satellite models, and extends these enhancements into more capable and longer-lived revenue-producers for our customers," Krekel added. "As a result, nine HS 702 satellites are currently on order from four different customers."

The HS 702, when fully deployed, is 102 feet in length and 29.5 feet wide. At time of launch, Galaxy 11 will weigh 9,886 pounds. To achieve higher power and longer life, the solar array of the HS 702 carries angled reflector panels along both sides of the solar wings, forming a shallow trough that concentrates more of the sun's rays onto the solar cells. The dual-junction solar cells are among the most efficient available, able to convert nearly one-quarter of the sun's rays into spacecraft power.

In order to handle the increased heat generated by this higher-power satellite, the bus and payload thermal environments on the HS 702 spacecraft have been separated, and the heat radiators have been substantially enlarged. This results in a cooler, more stable thermal environment for both the spacecraft bus and the payload. The deployable radiators use flexible heat pipes, which make it possible to utilize more of the radiators' surface for heat dissipation.

The HS 702 also carries Hughes' established xenon ion propulsion system, XIPS. Unlike its 13-centimeter predecessor, carried on the HS 601HP satellite model and used for north-south stationkeeping, the 25-centimeter XIPS thruster will perform all stationkeeping maneuvers and orbit-raising.

The primary benefit of XIPS is its fuel efficiency; up to 90 percent of spacecraft propellant mass can be eliminated by using XIPS. The HS 702 XIPS thrusters require only 5 kg of xenon fuel per year. The bottom-line benefit of XIPS is that it allows for the addition of more revenue-producing payload.

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. PanAmSat plans to launch seven additional satellites by mid-2001.

HSC is the world's leading manufacturer of commercial communications satellites, having built nearly 40 percent of those in operation. It also is a major supplier of spacecraft and equipment to the U.S. government, and a builder of weather satellites for the United States and Japan. HSC is a unit of Hughes Electronics Corp. Hughes Electronics is the world's leading provider of digital television entertainment, and satellite and wireless systems and services.

Flight data file
Vehicle: Ariane 44L
Payload: Galaxy 11
Launch date: Dec. 22, 1999
Launch window: 0050-0100 GMT (1950-2000 EST on 21st)
Launch site: ELA-2, Kourou, French Guina

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