Second-Generation Spacecraft for AsiaSat

Height stowed	4 m (13.1 ft)
Width stowed	3.1 m (10.1 ft)
Solar arrays deployed	26.2 m (85.8 ft)
Antennas deployed	10 m (32.9 ft)
Weight  in orbit    Beginning of life	2534 kg (5581 lb)

Asia Satellite Telecommunications Co. Ltd. (AsiaSat) selected Hughes Space and Communications International, Inc., in February, 1996 to build a Hughes 601HP (for high-power) satellite, provide a launch vehicle, and perform ground station upgrades. The satellite, AsiaSat 3, was to serve Asia and neighboring regions. In October 2000, Hughes Space and Communications Company became Boeing Satellite Systems, Inc.

AsiaSat 3 was launched on December 25, 1997, aboard a Proton rocket from the Baikonur Cosmodrome in Kazakhstan. The launch failed, however, in the fourth stage of the launch vehicle's second burn. Designed to last 110 seconds, it cut off prematurely after 1 second. As a result, AsiaSat 3 never reached geosynchronous orbit.

In March 1998, AsiaSat ordered a replacement satellite from Hughes. Designated AsiaSat 3S, the new satellite is a replica of AsiaSat 3.

Hughes provided the first AsiaSat satellite, AsiaSat 1, a Hughes 376 spin stabilized satellite. It was launched in 1990.

The body-stabilized AsiaSat 3 was to be used primarily for television distribution and telecommunications services throughout Asia, the Middle East, Australasia, and the Commonwealth of Independent States, with multiple spot beams for selected areas. It carried 28 active C-band transponders and 16 active Ku-band transponders. The C-band transponders were powered by 55-watt traveling wave tube amplifiers (TWTAs). The Ku-band transponders used 138-watt TWTAs.

As a high-power Hughes satellite model, AsiaSat 3 was to generate up to 9900 watts using two sun-tracking four-panel solar wings covered with gallium arsenide solar cells. A 29-cell nickel-hydrogen battery was to provide full power to the spacecraft during eclipse operations. The satellite was to use a bipropellant propulsion system for stationkeeping.

AsiaSat 3 had two 107-inch diameter Gregorian shaped-surface antennas. One of these antennas, to operate in C-band and to provide broad-area coverage of Asia and Australasia, was mounted on the east side of the satellite. The other antenna, to operate in Ku-band and to provide focused-area coverage of East Asia, was mounted on the west side.

Focused area coverage of South Asia was to be provided by a 50-inch-diameter, dual-gridded shaped reflector operating in the Ku-band. A 40-inch-diameter Ku-band steerable spot-beam antenna was to provide the spacecraft with the ability to direct 5-degree coverage of any area on the Earth's surface visible to AsiaSat 3 from its orbit location. Both of these antennas were mounted on the nadir side of the spacecraft.

The HS 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.

During launch, the solar wings fold alongside the spacecraft bus and the reflectors fold on top of the spacecraft bus. After separation from the launch vehicle in transfer orbit, the satellite's on-board 490-Newton (110 lbf) liquid apogee motor is fired to circularize the orbit at the 36,000 km (22,300 miles) altitude. Stationkeeping is accomplished with 12 conventional bi-propellant thrusters. Once on-station, the satellite would have weighed approximately 2500 kg. AsiaSat 3 was to operate from the orbital position of 105.5° East longitude.

AsiaSat 3, as well as AsiaSat 1, was to be controlled from an integrated satellite control facility, built by Hughes and located in Hong Kong.

The Hughes 601 is the most-purchased commercial communications satellite model. Boeing Satellite Systems is the world's leading manufacturer of geostationary commercial communications satellites, and is also a major supplier of spacecraft for communications and space exploration to the U.S. government and builder of weather satellites for the United States and Japan.

Public Relations
Boeing
P.O. Box 92919 (S10/S323)
Los Angeles, CA 90009
USA
(310) 364-6363
www.boeing.com/satellite