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AMSC 1


American Mobile Satellite Corporation 1
Also called MSAT 2

General


Designation 23553 / 95019A
Launch date 7 Apr 1995
Country of origin United States
Operator AMSC
Mission Telecommunications
Geostationary orbit see below
Launch vehicle Atlas Centaur

Operated by MSV (successor of Motient Services aka AMSC).
This satellite is a twin of MSAT 1. Both satellites were ordered at the same time (with separate contracts). Both operators will provide complementary mobile telephone, radio, data, and positioning service to land, aviation, and maritime users. Each operator also will provide the other with backup and restoration capacity.

While testing a transmission was sent to the satellite which caused certain components of the communication payload to overheat. The overheating damaged one of eight output hybrid matrix ports that serve the spotbeams covering the Eastern and Central United States. The other seven hybrid ports are operating in accordance with specifications. The remaining four spotbeams, covering the Mountain and Western portions of the United States, Alaska, Hawaii and the Caribbean, were not affected. Furthermore, adjustments in the operation of the satellite will be made to compensate for the power loss.

The satellite experienced in mid-1995, on separate occasions the shutdown of two solid state power amplifiers (SSPA) serving the Mountain, Central, Alaska/Hawaii and Caribbean spotbeams. These spotbeams were designed to be served by eight SSPAs with two spares. As a result of these unusual occurrences, AMSC is currently operating these spotbeams in a seven SSPA configuration which preserves one spare SSPA for such spot beams.

Was to be leased to African Continental Telecommunications Ltd (ACTEL) of Gibraltar through 2003. Cost: $182 million. ACTEL cancelled the lease in 1999.

The license this satellite expired on 31 Dec 2016 and extension till 31 Dec 2018 was awarded to Ligado Networks Subsidiary LLC

Location


Begin End Position
L: 7 Apr 1995 Nov 2010 100.95°W
Dec 2010 Sep 2018 103.3°W
Sep 2018   106.5°W
Went inclined in Nov 2004.


sat-index articles


Technical data



Specifications


Prime contractor Hughes
Hughes (bus) and SPAR Aerospace (payload)
Platform HS-601
Mass at launch 2550 kg
Mass in orbit 1510 kg
Dimension 2.5 m x 3.5 m x 7.9 m
Solar array 20.96 m span
Stabilization 3-axis
DC power BOL: 3600 W
Design lifetime 12 years

Springback antennas: 6.7 x 4.9 m x 20 kg (for launch the 2 antennas as rolled together into a 4.9 m high cone shape atop the satellite)

L-band (1545-1559/1646.5-1660.5 MHz)


Main transponders 16
Backup transponders 4
Power 38 W (SSPA)
Bandwidth  
Coverage North America (4 spot beams)
Alaska and Hawaii (1 beam)
Caribbean (1 beam)
EIRP max 58 dBW

Total bandwith: 3200 x 5 KHz

Each beam transponder is equipped with eight surface acoustic wave filters covering the 29 MHz L-band allocation, allowing selection of filters to math traffic needs and to coordinate with other international users. Frequency reuse is incorporated between the North American east and west beams. The beams are combined into two L-band power pools, one covering the east and central beams, and the other covering the remaining service areas. Each power pool is generated by a hybrid matrix amplifier assembly.

Ku-band


Main transponders 2
Backup transponders 2
Power 100 W (TWTA)
Bandwidth 24 MHz
Coverage CONUS, Caribbean, Canada, Alaska and Hawaii
EIRP max 36 dBW
Polarization linear V
Frequencies 10.760-10.910 GHz

The downlink frenquencies can be mapped to: 10.760, 10.790, 10.820, 10.850, 10.880 or 10.910 GHz.


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