An artist's concept of the Galaxy 10R communications satellite in space. Photo: Hughes

Hughes Space and Communications Company (HSC) has begun using an innovative, high-performance engine to boost its satellites toward their final orbit.

The first use of the engine was in January on the Galaxy 10R satellite, a Hughes 601HP model built for PanAmSat Corporation. PAS-9, another Hughes 601HP satellite being built for PanAmSat, will also use this new engine. It is scheduled for launch this year.

Galaxy 10R received a 34,000-kilometer (22,000-mile) lift from its new on-board liquid apogee engine (LAE), built by Kaiser Marquardt of Van Nuys, Calif. The engine raised the satellite to a circular geosynchronous orbit after Galaxy 10R was successfully placed in an elliptical transfer orbit (200 km, or 124 miles, at its low point) by an Ariane 4 rocket Jan. 24. Hughes satellite engineers then put Galaxy XR through its paces, deploying solar wings and antennas and testing the payload. They also activated the xenon ion propulsion system (XIPS), which provides stationkeeping for the satellite.

The new engine provided the heavy lifting with its 445 Newtons (100 pounds) of thrust, using the standard satellite bipropellants, monomethyl hydrazine and nitrogen tetroxide. The XIPS uses xenon gas to provide the small amounts of thrust (17.7 milliNewtons) necessary to keep the satellite on station during its expected 15 years of service. (Hughes Electron Dynamics builds XIPS, which has been carried on Hughes satellites since 1997.)

Kaiser Marquardt calls the apogee engine its High Performance Thruster, and conducted space qualification tests on the advanced materials incorporated into this design for Hughes. This particular design is exclusive to Hughes for use on its 601 and 702 series of satellites.

Because it uses advanced materials, the new, high-performance engine operates about 700 degrees Fahrenheit hotter than conventional satellite engines, resulting in greater propellant efficiency and higher performance. It provides a specific impulse of approximately 322 seconds as compared to the 315 seconds provided by standard apogee motors used by HSC. This means less fuel is required to reach geostationary orbit, which in turn results in reduced launch cost, increased payload mass capability, increased satellite life or any combination thereof. The benefits vary with the satellite's mission and the launch vehicle used. For example, it could allow about a 120-pound payload or satellite mass increase for a Hughes 601 satellite.

Galaxy 10R facts
Spacecraft	HS 601HP
Life	15 years
Orbital Slot	123 degrees West
Dimensions	86 feet long 23 feet wide
Weights	7,661-lb at launch 4,711-lb in orbit
Power	2 solar wings with 4 panels each 8.8 kw beginning of life
Payload	24 C-band transponders 24 Ku-band transponders
Source: Hughes Space and Communications

Besides using the new boost engine, Galaxy XR is also the first spacecraft to fly Propellant Management Device (PMD) tanks employing the HSC-patented etched disk concept. The PMD consists of a series of paper-thin metallic disks placed in a stack and used to draw propellant out of the tank. The robust, lightweight PMD design provides gas-free propellant delivery during spinning as well as zero-gravity mission phases with substantial margins. It results in greater operational flexibility for the spacecraft.

Dowty Space Projects of the United Kingdom designed, developed, qualified and built the tanks to HSC's specifications.

"Hughes is dedicated to maintaining our technology leadership role in the industry, and to applying that technology to add value for our customers," said HSC President and CEO Tig H. Krekel. "And we rely on top-quality suppliers such as Kaiser Marquardt and Dowty to keep us on the leading edge."

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 Corporation.

PanAmSat (Nasdaq:SPOT), based in Greenwich, Conn., is a leading provider of global video and data broadcasting services via satellite. The company builds, owns and operates networks that deliver entertainment and information to cable television systems, TV broadcast affiliates, direct-to-home TV operators, Internet service providers, telecommunications companies and corporations. With 21 spacecraft in orbit today, PanAmSat has the world's largest commercial geostationary satellite network. The company will expand its global fleet to 24 spacecraft by mid-2001. PanAmSat is 81 percent owned by Hughes Electronics.