Figure 2.11
The ATS-6 satellite in orbit. (
Source:
NASA.)
2.2.3.5
Japan
As the leading industrialized country in Asia, Japan has aggressively sought to be
a power in the field of satellites and satellite communication systems. The Japanese
government funded several satellite projects for experimental and industrial devel-
opment purposes.
The first true Ku-band direct broadcast satellite (DBS) satellite was developed
by GE for the national broadcast network, NHK. There were technical problems
with high-power traveling wave tube amplifiers (TWTA) and their associated power
supplies, so the spacecraft failed to meet expectations. A follow-on DBS program
in Japan included satellites designed and built by RCA Astro Electronics and
Hughes. Interestingly, the Japanese government became one of the most successful
DBS operators in the world (in terms of the number of viewers) by offering a
package of U.S. programming material. Regular cable channels like ESPN and
Financial News Network (now merged into CNBC) and TV networks like ABC
and CBS were combined into a continuous feed of non-Japanese material that was
available only on DBS. Another unique feature of the system is that it was used
2.2
Evolving Satellite Coverage
57
Figure
2.12
An
illustration
of
the
spot
beams
produced
by
the
ACTS
satellite,
using
fixed
and
switched
Ka-band
channels.
(
Source:
NASA.)
58
Evolution of Satellite Communication
to transmit high-definition TV (HDTV) on a trial basis. The NHK channels were
joined by private service providers who used the same space segment to deliver
subscription services.
Satellite communications began to be privatized in 1987, when licenses were
granted to Japan Communications Satellite Corporation (JCSAT) and Space Com-
munications Corporation (SCC). JCSAT was an extremely interesting company
because of its ownership: 40% Itochu, 30% Mitsui and Company (both highly
respected Japanese trading companies), and 30% Hughes. The combined company
successfully launched two Ku-band satellites and largely cornered the domestic
market. These Ku-band satellites became the delivery system for Sky PerfecTV, a
successful Japanese DTH operator. SCC, heavily backed by Mitsubishi, the largest
trading group in Japan, was plagued by problems with its first satellites supplied
by Ford Aerospace (later Space Systems/Loral) but eventually went into operation
using satellites built by Loral and Hughes. A third satellite operator, Satellite Japan,
never went into business, but the partners ended up buying out Hughes’ interest
in JCSAT (renamed JSAT). Subsequently, JSAT has grown into the largest satellite
operator in Asia and was renamed Sky Perfect JSAT.
2.2.3.6
India
India has conducted an extensive scientific and technological research program in
space, under the stewardship of the Indian Space Research Organization (ISRO).
Headquartered in Bangalore, India’s fifth-largest city and the capital of the southern
state of Karnataka, ISRO has created a domestic industrial base capable of designing
and building spacecraft and placing them in orbit with an indigenous rocket. The
first domestic satellite for India, called INSAT 1, was launched in 1981 and per-
formed the dual function of providing communication services at C- and S-band (for
TV broadcast) and meteorological imaging. The first-launched of these complicated
three-axis spacecraft, designed and built by Ford Aerospace, reached orbit but
experienced technical problems with deployment of antennas and operation of
propulsion. A modified second spacecraft was launched in 1983 and met its service
objectives.
ISRO successfully transferred technology to develop INSAT 2, the second-
generation spacecraft that continued to offer domestic transponders and weather
imaging. A trend toward limited privatization of telecommunications started in
1995, and other satellites were introduced into the domestic market.
2.2.3.7
Middle East
After many years of planning and discussion, the Arab League countries embarked
in 1976 on a regional system called the Arab Satellite Communications Organiza-
tion. It was structured along the lines of EUTELSAT, with membership including
Algeria, Bahrain, Egypt, Iraq, Djibouti, Jordan, Kuwait, Lebanon, Libya, Maurita-
nia, Morocco, Oman, Palestine, Qatar, Saudi Arabia (the largest and most powerful
member), Somalia, Sudan, Syria, Tunisia, the United Arab Emirates (UAE), and
Yemen. The satellite and system were to become known as Arabsat.
2.2
Evolving Satellite Coverage
59
Design and construction of the first series of satellites were contracted to
Aerospatiale, with a significant portion of the three-axis technology provided by
Ford Aerospace. The satellites, first launched in 1985, had communication capabil-
ity similarly to Insat in that C- and S-band services are possible. What ensued was
a number of years of technical and political difficulties, which negatively affected
the initial business prospects. Eventually, Arabsat developed a more functional and
businesslike structure and became profitable. Arabsat 2B, for example, provides
TV and telecommunication services at 30.5
°
East. All services are delivered at
Ku-band, including DTH television.
A number of other companies in the Middle East have embarked on their own
domestic and regional satellite programs. Nilesat 901 was built by EADS Astrium
for the Egyptian Satellite Company. Turksat, from Turk Telekomunikasyon AS of
Turkey, was launched in August 1994, providing Ku-band capacity to the region.
Another program of interest is Thuraya, a GEO mobile system supplied by Boeing.
Thuraya was developed by Etisalat, the public telecommunications operator in the
UAE, and a consortium of telecommunication operators in the Middle East. Capac-
ity is also provided to the Middle East by such established operators as INTELSAT,
EUTELSAT, and AsiaSat. A cooperative spacecraft program called Amos 1 involved
the Israel Aircraft Industries along with Daimler Aerospace and Alcatel. This
Ku-band spacecraft was successfully launched on May 15, 1996, on an Ariane 4
rocket. In addition to a Middle East beam, Amos 1 has a Central Europe beam
that delivers HBO programming to Hungary, Poland, and the Czech Republic.
Amos 2 and 3 have since been launched and colocated with Amos 1 at 4
°
W.
2.2.3.8
Latin America
Latin America embraced satellite communication almost immediately after the
launch of Early Bird. With vast expanses of underdeveloped territory and difficult
natural obstacles between its countries, Latin America proved to be a loyal supporter
of the INTELSAT system. Mexico (technically in North America but close to
South America by virtue of a common heritage) and Brazil (the largest and most
industrialized economy in the region) were among the first in the world to construct
Standard A Earth stations near their capital cities. Later on, Mexico and Brazil
initiated their satellite systems in 1982 using Hughes Aircraft designs. In the case of
Brazil, the first two satellites were assembled in Canada by Spar (now MacDonald,
Dettwiler and Associates, Ltd.) and provided 24 C-band transponders each. Each
satellite incorporated a hybrid C- and Ku-band payload, intended to provide a
variety of communications services to large- and small-diameter Earth stations.
One important Ku-band application was the extension of tele-education to remote
villages in Mexico, something that was previously started with terrestrial micro-
wave.
Both Mexico and Brazil (Brasilsat) were successful in implementing their space
segments in 1985. Other Latin American nations have taken action to develop
their own orbit resources. Argentina initiated its own satellite program called
Nahuel in the 1990s, contracting with DASA for the system. The unique aspect
of Nahuel is that the contract grants DASA the right to operate the satellite to
provide services in Argentina and around the region. Colombia has applied for
60
Evolution of Satellite Communication
orbit positions beginning in 1980 but had not initiated construction of its own
satellite at the time of this writing. Another regional project named Simon Bolivar
(later changed to AndeanSat) has been under development by the nations of the
Andean Pact, which includes Colombia, Venezuela, Ecuador, Peru, and Bolivia.
Venezuela may undertake this project by employing satellite and launch technology
from China.
In the 1990s, Mexico and Brazil were in a position to maintain and expand
their respective satellite systems. Telecommunicaciones de Mexico (Telecomm), the
government agency responsible for Morelos, contracted with Hughes Space and
Communications International for two medium-power hybrid spacecraft, Solidari-
dad 1 and 2. An Ariane 4 rocket launched Solidaridad 1 on November 20, 1993,
resulting in the spacecraft being placed at 109.2 degrees west longitude. The satellite
was the first to carry L-band in addition to C- and Ku-bands. The Mexican govern-
ment spun off the satellite business as SatMex, which was acquired by Telefonica
Autry and Loral Space and Communications. Embratel, the Brazilian long distance
telephone company and operator of the Brasilsat system, was sold to MCI of the
United States in 1998. Brasilsat, on the other hand, was purchased by SES and
renamed StarOne.
2.2.3.9
Africa
The African continent, with the exception of the Middle East, still remains the
area with the lowest level of economic and telecommunications development in
the world. However, it cannot be ignored when considering markets for satellite
capacity and, ultimately, domestic spacecraft. Telephone density in the region is
the lowest in the world at around 5 per 100, although an acceleration is under
way through installation of new lines and cellular coverage.
African nations have long been members and users of the INTELSAT system.
That contributed to the telecommunications development of many countries,
allowing the more politically stable foreign investment in natural resource and
transportation industries. The pooling of demand for those transponders led to the
creation of Regional African Satellite Communications (RASCOM), a 42-member
cooperative of public operators. RASCOM-QAF1 was contracted to Alcatel, but
the launch in 2008 was unsuccessful. Meanwhile, Nigeria lofted its first domestic
satellite in 2007.
Do'stlaringiz bilan baham: |