ASC 2

Otherwise known as Spacenet 4, SN-4

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General

Designation	21227 / 91028A
Launch date	13 Apr 1991
Country of origin	United States
Mission	Telecommunications
Geostationary orbit	see below
Launch vehicle	Delta 2 #204

[early 1998] Would have technical malfunctions in the Ku-band

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Location

Begin	End	Position
L: 13 Apr 1991	Jan 2000	101°W
Feb 2000	Sep 2000	81°W
Nov 2000	Jan 2004	172°E
Jan 2004	Apr 2006	172°E, inclined

After its relocation over the Pacific, the satellite provides trans-pacific communications (mainly data). It covers Northern Pacific rim (Russia, Japan, Korea, part of China, Taiwan, The Philippines, part of Vietnam), Hawaii, Alaska, and the US & Canada West coast.

In mid-2005, the antennas are repointed North to provide Ku-band capacity for aircraft operating in the area.

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End of life

Out of service	Apr 2006
Cause	Moved to the junk orbit

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External resources

sat-index articles

Technical data

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EIRP coverage (dBW) (before relocation)

C-band, 36 MHz transponders
C-band, 72 MHz transponders
Ku-band

Specifications
C-band transponder frequency chart
Ku-band transponder frequency chart

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C-band

Main transponders	18
Backup transponders
Power	36 MHz: 12 of 8.5 W (SSPA) 72 MHz: 6 of 16 W (TWTA)
Bandwidth	12 of 36 MHz 6 of 72 MHz
Coverage	Pacific
EIRP max	37 dBW
Polarization	linear

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Ku-band

Main transponders	6
Backup transponders
Power	6 of 16.2 W (TWTA) 2 of 30 W (TWTA)
Bandwidth	72 MHz
Coverage	Pacific
EIRP max	46 dBW
Polarization	linear H
Frequencies	uplink: 14.0-14.5 GHz downlink: 11.7-12.2 GHz

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