AMSC 1

USA

Spacecraft n°:

USA satellite n°:

American Mobile Satellite Corporation 1
Also called: MSAT-2

Launch data:

Designation	23553 / 95019A
Launch date	07 Apr 1995 - 23:47 UT
Launch site	CC, LC-36A
Launch vehicle:	Atlas 2A (AC-114)
Operator	AMSC
Mission	Telecommunications
Geostationary orbit on:
Perigee / Apogee	km
Eccentricity
Inclination	deg
Period	min
Location	101°W

Operated by 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.

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

Location:

Begin	Position	Remarks
	101°W
5 Mar 2008	259° E	manoeuvred off-station

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) Carribean (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, Carribean, 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.

Ref.: #7, #15, #225 - update: 15.08.08

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