Fixed-Satellite Services
Satellites providing Fixed-Satellite Services (FSS) transmit
radio communications between ground Earth stations at fixed locations,
hence the name. (All satellite-transmitted information is carried in the
form of radio-frequency signals.) Any number of satellites may be used
to link these stations. Earth stations that are part of fixed-satellite
services networks also use mobile units that move to temporary broadcast
points, such as sporting events or newsworthy occurrences. In addition
to such video programming, FSS satellites provide a wide variety of services.
These services might include paging networks and point-of-sale support,
such as credit card transactions and inventory control.
The following SS/L-built satellites provide FSS.
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Broadband-Satellite Services
Broadband satellites transmit information, primarily Internet
connections and data services, at high speed for individuals and organizations
of all types. Markets for broadband services include also include interactive
TV, wholesale telecommunications, telephony, and point-of-sale communications,
such as credit card transactions and inventory control.
The following SS/L-built satellites provide Broadband-Satellite Services.
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Upcoming SS/L satellites providing Broadband-Satellite Services.
Direct-Broadcast Services
Direct-broadcast satellites (DBS) transmit signals for direct
reception by the general public, for instance, satellite television. Satellite
signals are sent directly to users through their own receiving antennas
(satellite dishes) in contrast to satellite/cable systems in which signals
are received by a ground station, and re-broadcast to users by cable.
The following SS/L-built satellites provide DBS.
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Weather
These satellites are typically self-contained
systems that carry their own communications systems for distributing the
data they gather in the form reports and other products for analyzing
the condition of the environment. Satellites are particularly useful in
this case because they can provide continuous coverage of very large geographic
regions. Air Traffic Control (ATC) The following SS/L-built satellites provide
weather and/or ATC services. International
Space Station
Government Communications and
Sensors
Government communications use different
frequency bands and waveforms than commercial communications. Additionally,
the military's needs for secure and undetectable communications require
different, and often less efficient methods of transmitting information.
Government sensors, beyond environmental
applications, gather intelligence in various forms, including radar, infrared
imaging, and optical sensing.
The following SS/L-built satellites provide
Government Communications and/or Sensors.
Communications Repeaters
and Payloads Payloads are the mission-specific equipment
packages that perform revenue-generating tasks for the satellite's owner.
Payloads might include transponders, which receive, amplify, and send
radio-frequency signals that encode all types of information; receive
and transmit antennas; or optical or other sensing equipment that gathers
images or environmental data.
SS/L provided communications repeaters
and/or payloads for the following satellites.
Weather satellites carry highly sensitive imagers and sounders to monitor
the Earth's environment, including the vertical thermal structure of the
atmosphere; the movement and formation of clouds; ocean temperatures;
snow levels; glacial movement; and volcanic activity. Large-scale computers
use this data to model the entire earth's atmosphere and create weather
forecasts such as those provided by national weather services in the U.S.
and abroad.
Satellites can provide two types of communication services to support
air traffic control functions. Air traffic control satellites collect
navigation data from ground monitoring systems and broadcasts it to aircraft
aloft, greatly increasing the navigational accuracy and reliability of
the global positioning system (GPS) for aircraft location and safe take-offs
and landings. These satellites also provide a highly reliable digital
communications path for air traffic controllers and pilots to share vital
flight information.
The largest power storage system on-orbit is Space Systems/Loral's nickel-hydrogen
battery system aboard the International
Space Station. The system stores and manages the power generated by
the Space Stations huge solar arrays. It consists of battery orbital replacement
units, battery charge/discharge units, and sequential shunt units.
Providing X-band satellite communications
services to governments is a new commercial application with substantial
growth potential. SS/L will design and build two X-band satellites, which
will be available for lease to government users in the United States and
Spain, as well as other friendly and allied nations within the satellites'
extensive coverage areas.
All satellite-transmitted information, whether
it is originally video or data or whatever, is carried in the form of
radio-frequency signals. Communication repeaters comprise the collection
of elements that receive, amplify, and re-transmit these radio-frequency
signals, usually at a different frequency level than the original signal.
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