Dateline Asia
The APSTAR Satellite System
by Mark Long
Portions of this
article first appeared in the
July/August 2000 issue of Broadband Asia magazine
© copyright 2000 MLE INC. All Rights Reserved.
Established in
1992, APT Satellite Holdings Limited (APT) is a Hong Kong based company that provides
satellite transponder leases and services for the broadcast and telecommunication sectors
of the Asia/Pacific region. In 1999, APT achieved a net profit attributable to
shareholders of HK$375 million (1998: HK$59 million). The earning per share was 89.18 HK
cents, or a 532 percent increase from the previous year. The company is listed on both the
Hong Kong and New York stock exchanges.
APT greatly benefits from its close relationship with satellite partners on the Chinese mainland such as ChinaSat. During 1999, the Chinese market generated more than 58 percent of the company's revenues. The US market came in a distant second, generating just 14 percent of the company's annual turnover.
APT's principal Shareholders are:
- China Telecommunications Broadcast Satellite Corporation (ChinaSat);
- China Aerospace Corporation;
- Chia Tai International Telecommunication Co., Ltd.;
- China Travel Fok Tai (Macau) Ltd. (a corporation with 50 percent equity owned by China Travel Service (Holdings) Hong Kong Ltd.);
- SingaSat Pte., Ltd. (a wholly-owned subsidiary of Singapore Telecommunication Limited);
- and Kwang Hua Development and Investment Ltd. (a Hong Kong corporation jointly owned by the Ruentex Group and China Development Corporation).
THE APSTAR-I & APSTAR-IA SATELLITE
PLATFORMS
APT currently operates three satellites: APSTAR-I, APSTAR-IA and APSTAR-IIR. The
three spacecraft collectively cover more than 100 countries in Asia, Europe, Africa and
Australia--an area that represents 75 percent of the world's population. APT also operates
a 19,000 square foot satellite control centre located at the Tai Po Industrial Estate in
Hong Kong. The facility employs about forty satellite engineers and communications
specialists, who control and continuously monitor the three APSTAR satellites. The Tai Po
facility is equipped with six antennas (13m, 5.5m, 11m, 6.1m and 9m for C-band, and 8.1m
for Ku-band) and nine transmission facilities as well as associated equipment and
facilities.
On 21 July 1994, a Chinese Long March 3 rocket deployed APSTAR-I to an orbital assignment of 138 degrees East Longitude. The satellite is expected to remain in service until mid-2004 when it is scheduled to be replaced by APSTAR V. Launched on 3 July 1996 to 134 degrees East Longitude, APSTAR IA has an estimated mission life of ten years.
Based on the enormously successful Hughes HS-376 spin-stabilized spacecraft bus, each satellite carries 24 active C-band transponders (with six inactive spares) powered by 15-watt traveling-wave tube (TWT) amplifiers. Four of the transponders aboard either spacecraft offer 72 MHz of bandwidth, while each of the remaining twenty transponders has a bandwidth of 36 MHz.
During 1999, the average utilization rate for capacity aboard APSTAR-I was 58.6 percent, while APSTAR-IA achieved a substantially higher utilization rate of 69 percent. The annual lease charge for a transponder on either satellite was 1.5 million U.S. dollars as of year-end 1999.
APSTAR-I's satellite footprint covers China, Hong Kong, Indonesia, Japan, Singapore, and Vietnam. On APSTAR IA, this coverage beam has been expanded slightly to include India and Pakistan as well. The average radiated power that each of satellite generates over China is 35 dBW.
Power, however, is not the only important criteria for those customers who downlink signals from the APSTAR satellites. The ultimate figure of merit for satellite receiving systems is called the G/T (pronounced "Gee" over "Tee). This term represents the gain of the receiving antenna divided by its noise temperature. APSTAR-I and APSTAR-IA are located at 134 and 138 degrees East Longitude, respectively. These orbital positions over the Pacific Ocean present low elevation angles to most of the receiving antennas located on the Asian mainland. The lower the elevation of the dish, the lower its G/T performance will be at the receiving location.
To correct for this deficiency, the telecommunication authority of the PRC has applied for new orbital positions for the deployment of future APSTAR spacecraft. The orbital assignments of 93, 85.5 and 89.5 degrees East Longitude are located directly south of the Chinese mainland. From these new orbital slots, future APSTAR satellites will present much higher elevation angles so that virtually all receiving antennas can achieve higher G/T performance levels than what can be obtained from either APSTAR-I or APSTAR-IA today.
APSTAR SATELLITE TRAFFIC
According to the company's 1999 Financial Report, more than 70 percent of APT's
revenues came from the lease of satellite capacity to regional TV broadcasters. The
customer base of the APSTAR-I and APSTAR-IA satellites currently includes TV programmers
such as HBO, Walt Disney, Sony, ESPN, Turner, WTCI, MRFT, ChinaSat, CCTV, CETV, China
Unicom and many others.
In a bid to increase its revenue-generating abilities within the telecom sector, APT recently began offering Very Small Aperture Terminal (VSAT) systems and services to customers on the Asian mainland. In September of 1999, APT signed an agreement with the People's Bank of China, Guangzhou Branch, for the construction of a VSAT network that provides the bank with two-way video conferencing, telephone and data delivery systems. Upon completion of the project, the Guangzhou Branch will be connected to twenty cities in Guangdong province via a network of two-way VSAT terminals.
In 1999, the Hong Kong Special Administrative Region (SAR) government awarded a license to APT that allows the company to uplink and downlink broadcast TV signals on behalf of customers who are not located in Hong Kong itself. To implement this new service, APT has formed an alliance with business partner Combo-Orientstar Satellite TV Ltd., a broadcasting agent that focuses on marketing and distribution of television programmes.
APT's integrated digital television programme transmission platform receives and decodes TV programmes from a variety of sources and then digitally compresses and encrypts the signals before uplinking the converted signals to APSTAR-IIR. A Ku-band transponder aboard this satellite then relays the programmes to authorised end-users located within the satellite's intended coverage area. Within the PRC, authorised end-users are allowed to receive and decode these signals through the use of designated receiver/decoders.
All
spacecraft in the HS 376 satellite line have two telescoping cylindrical solar panels and
an antenna or antenna array which folds down for launch. APSTAR 1 and 1A measure 2.2
meters in diameter and a compact 3.1 meters tall when stowed for launch. With the solar
panels deployed and the antenna unfolded in orbit, they measure 7.5 meters.The solar
panels produce 1130 watts at beginning of life. During a solar eclipse, two super
nickel-cadmium batteries provide power uninterrupted service. With station keeping fuel
the satellites weigh about 726 kg at beginning of life on-orbit. Each satellite’s
transmit and receive beams are created by a 2-meter round antenna with two reflecting
surfaces. One is sensitive to vertical polarisation and the other to horizontal. Separate
microwave feedhorn networks are used to generate the horizontal and vertical senses of
linear polarisation.
(Apstar 1 graphic courtesy of Hughes Space and Communications International.)
APSTAR II-R
APSTAR-IIR is a dual-band satellite deployed to an orbital
assignment of 76.5 degrees East Longitude orbit on 17 October 1997. In 1999, APT leased
100 percent of the capacity aboard this spacecraft to Loral Skynet of the United States in
exchange for US$ 273 million. This dual-band spacecraft is now part of Loral's existing
worldwide constellation of high-powered satellites. APT, however, remains the title owner
for this spacecraft and continues to exercise full control of the satellite through its
control centre in Tai Po, Hong Kong.
Based on Loral’s FS-1300 spacecraft bus, Apstar II-R carries a communications payload comprising twenty-eight C-band transponders powered by 60 watt travelling-wave tube amplifiers and sixteen Ku-band transponders powered by 110 watt travelling-wave tube amplifiers. The spacecraft has been designed for a fifteen year mission life.
(Photo courtesy of Space Systems Loral.)
APSTAR
BROADCAST SATELLITE SERVICE (BSS)
APT intends to use the funds that it acquired through its lease of APSTAR-IIR to Loral Skynet to purchase and launch several new satellites, including two high-power Ku-band spacecraft capable of delivering direct broadcast satellite (DBS) services to private households. The PRC government is considering a broadcast satellite service (BSS) application that APT has submitted for its consideration. Once given the green light, APT intends to launch a new satellite called APSTAR IV that will be capable of transmitting as many as 100 digital TV services to locations throughout Southeast Asia as well as the PRC.
(Apstar 2R photo courtesy of Space Systems Loral.)APT may not need much lead-time to launch its proposed BSS platform. Space Systems/Loral already has constructed two high-power Ku-band satellites with beams that have been optimized for coverage of the Asian mainland. Some design changes undoubtedly would be required in order to modify the two spacecraft to operate at orbital locations that the ITU has assigned to the Chinese government for broadcast satellite service use. However, both spacecraft could be completed and prepared for launch in far less time than it would take to design and build two new satellites from scratch.
The LSTAR satellites were originally built for Asia Broadcasting and Communications Network, Ltd., (ABCN) of Bangkok, Thailand. They were part of an ambitious plan for launching a regional BSS satellite system for Asia. Space Systems/Loral was forced to suspend construction on the two satellites when ABCN ran out of funds. It would not be surprising if the 1999 agreement between Loral Skynet and APT included some provisions governing APT’s eventual acquisition of these two satellites, which just happen to be ideal platforms for launching new DBS services within the region.
APSTAR II-R C-band coverage extends from the Asia/Pacific region to Europe, Russia, Africa, Middle East, India and Australia. The coverage for Ku-band includes mainland China, Taiwan, Hong Kong and Macao.
