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SKYNET 4E (25639)
COSPAR: 1999-009B | Alt Name: Skynet 4E
Image
Additional Sources
Launch Details
Launch Date
February 26, 1999
Launch Site
FRGUI
Launch Pad
ELA2
Launch Vehicle
Ariane 44L
Orbital Elements
NORAD ID
25639
International Designator
1999-009B
Epoch
Fri, 03 Jul 2026 21:24:52 GMT
Apogee
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Perigee
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Inclination
12.08°
Right Ascension
9.01°
Eccentricity
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Argument of Perigee
248.14°
Period
1454.11 min
Mean Motion
0.99 rev/day
Latitude
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Longitude
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Altitude
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Velocity
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Polar Plot
3D Visualization
Basic Satellite Info
Name
SKYNET 4E
Alternative Name
Skynet 4E
Type
Payload
Status
Non-operational
Owner
MOD
Country
United Kingdom
Constellation
N/A
Related Satellites
Major Events
N/A
Latest TLEs
1 25639U 99009B 26184.89227125 -.00000276 00000-0 00000-0 0 9995
2 25639 12.0781 9.0074 0001389 248.1435 120.1403 0.99029768 51326
Source: Celestrak
Summary
SKYNET 4E, also known as Skynet 4E, is a military communication satellite launched on February 26, 1999, from the ELA2 launch pad at Kourou using an Ariane 44L vehicle. The spacecraft measures 2.1 meters in length and 1.9 meters in diameter with a span of 16 meters and has a dry mass of 719 kg. It was manufactured by MMSS for the UK Ministry of Defence (MOD) under the ECS-Bus configuration. SKYNET 4E is equipped with two deployable solar arrays, batteries, and various transponders including four SHF, two UHF, and two C-band for its communication mission. Its design includes a box shape with two panels, and it has an RCS of 5.2477. The satellite was designed to have a lifetime of six years.
Physical Characteristics
Length
2.1
Diameter
1.9
Span
16
Dry Mass
719
Launch Mass
823
Shape
Box + 2 Pan
Radar Cross Section
5.2477
Visual Magnitude
Unknown
Color
Unknown
Material Composition
Unknown
Technical Details
Payload
Skynet 4E
Purpose
Military communication
Mission
Military communication
Manufacturer
MMSS
Life Expectancy
6 years
Bus
ECS
Configuration
ECS-Bus
Motor
Star 30
Equipment
4 SHF transponders (all), 2 UHF transponders (all), 2 C-band transponders (#D-F)
Power System
2 deployable solar arrays, batteries
ADCS
Unknown
Transmitter Frequency
Unknown
Map
Next Pass
Azimuth Elevation Time (Local)
Start Azimuth
Max Elevation
Stop Azimuth
Time Until
Pass Duration
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