TV Satellite Designed for Wide Reach

The APSTAR II satellite was designed to serve two-thirds of the world's population--from China, Japan, and Vietnam on the east; to Russia, Eastern Europe, and India on the west; and to Australia on the south. APT Satellite Company, Ltd., of Hong Kong, ordered the high-power Hughes HS 601 spacecraft model in November 1993, as well as satellite control facility equipment and operator training.

APSTAR II was to complement the smaller Hughes-built APSTAR I and be used primarily for television broadcasting. APSTAR II was launched Jan. 26, 1995, on a Long March 2E rocket from Xichang, China, but it was destroyed in an explosion shortly after liftoff.

The APT/Hughes business relationship began in May 1992 with the signing of a contract for APSTAR I and an option for a second satellite. APSTAR I is an HS 376 spin-stabilized model having 24 transponders operating in C-band for a variety of communication traffic such as voice, data, and facsimile. The APSTAR I coverage encompasses North and Southeast Asia. APSTAR II, which was designed to be significantly larger and more powerful, used the body-stabilized HS 601 design. Its coverage area extended into Europe, Russia, India, and Australia. After the loss of APSTAR II, APT ordered APSTAR IA from Hughes. It is another HS 376 model similar to the first, with extended coverage to India and Pakistan. All three spacecraft were built at Hughes Space and Communications Company facilities in El Segundo, Calif. In 2000, the company became Boeing Satellite Systems, Inc.

Stowed (left); In Orbit (right)

APSTAR II was to have provided video services for program distribution and syndication; data services for business applications; and services for video, radio, data, and telephone transmission. The C-band payload, using 52-watt traveling-wave tube amplifiers (TWTAs), had 26 active and six spare transponders. The Ku-band payload had six active channels (with two spares) powered by 50-watt TWTAs and two high-power channels (with one spare) powered by 120-watt TWTAs.

Like others in the Hughes 601 series, the APSTAR II satellite consisted of a cube-shaped center payload section, with the solar panel wings extending from the north and south sides, and an antenna array. The Hughes 601 is composed of two modules: the primary structure, which carries all launch vehicle loads and contains the propulsion system, bus electronics, and battery packs; and a payload module, which holds communications equipment and isothermal heat pipes. Reflectors, antenna feeds, and solar arrays mount directly to the primary module, and antenna configurations can be placed on three faces of the bus. Such a modular approach allows work to proceed in parallel on both structures, thereby shortening the manufacturing schedule and test time.

APSTAR II was designed to generate 4300 watts with its two solar wings, each carrying four panels of K-4 3/4 solar cells. The APSTAR II configuration included two dual-surface, hexagonal reflectors, each with a diameter of 2.1 meters, located on the east and west sides. A 30-cell nickel-hydrogen battery was included to power the spacecraft during eclipse. APSTAR II used Hughes' advanced shaped-reflector technology, which concentrates the satellite's beam over targeted land areas while avoiding uninhabited oceans. Hughes' patented, highly efficient design eliminates the need for multiple feedhorn configurations.

For launch, the solar arrays and antennas were folded alongside the spacecraft, forming a compact arrangement of 2.7 meters by 4 meters by 3.6 meters. With the solar wings unfolded and the antennas deployed, APSTAR II measured 26 meters from end-to-end and 7 meters across. The bipropellant propulsion system included an integral 490-Newton (110 lbf) Marquardt liquid apogee motor plus thirteen 22-Newton (5 lbf) thrusters for stationkeeping.

APT Satellite Company was formed in 1992 by the China Yuan Wang (Group) Corp., China Telecommunications Broadcast Satellite Corp., Ever-Victory System Company, and the Chia Thai Group of Thailand to purchase APSTAR I. APSTAR I's mission is to provide infrastructure telecommunications, business communications, and television to the Asia Pacific region. With additional investment from companies in Singapore, Macao, and Taiwan, APT purchased APSTAR II for higher power and expanded coverage.