Lecture 2, Space Segment

Presentation / Lecture 2, Space Segment

Date Submitted: 06 June 2001

Written by RPC Telecommunications Ltd.. Website: http://www.rpctelecom.com

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This is the second in the series of general satcom tutorial lectures submitted by RPC Telecommunications.

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-Section 1
Orbit Theory: Kepler's Laws.
-Section 2
Orbit Theory: Formulae.
-Section 3
The Real World.
-Section 4
Types & Implications of Orbit.
-Section 5
Satellite Hardware.
-Section 6
Launch Vehicles.
-Section 7
Flight Plan & Maintaining Satellite In Orbit.
-Section 8
Stationkeeping & Stabilisation.

Launch Vehicles

Expendable Vehicles
  • Ariane (Europe)
  • Delta (USA)
  • Atlas Centaur (USA)
  • Proton (Russia)
  • Long March (China)
  • Japan + others?

Reusable Vehicles

  • STS - Space Shuttle (USA)
  • Europe (Hermes)?
  • Russia?

Unconventional Approaches

  • Cruise Missiles
  • Floating platforms


Vehicle GTO/kg GSO/kg
Delta 3194 900 480
Delta PAM-D 1250 670
Atlas-Centaur 2000 1070
Titan IIIC - 1400
Ariane 3 2400 1500


Space Transportation System (space shuttle) can deliver to LEO/Parking orbit only. Also the payload must have additional PAM/PKM to achieve GTO. Total STS payload bay launch capability is very large, but must take account of the support cradle and also the PAM stage.

All prices are quoted for a dedicated launch. Estimated prices are shown underlined:

Vehicle Mass to GTO GTO Inclination Reliability Cost (1993)
Ariane 44LP 3900kg 7 94.1% $92M
Ariane 5 6900kg 7 ? $120M
Atlas IIAS 3630kg 28.5 94% $137M
Long March 2E/HO 4800kg 28 92% $30M ($58M)*
SL-12 Proton-KM 4500kg to GEO N/A 98% $30-$40M
Titan III 4500kg 28.5 96.4% $120M
Titan IV Centaur 4500kg to GEO N/A >90% $200 - $300M
Delta II 1819kg 28.5 93.6% $50M
H-II 4200kg 30.5 ? $70M
HOTOL 3700kg ? >98% $1-$5M

*Long March have quoted a price of $30 million, but in order to protect the interests of western launch vehicles, the US has used the COCOM rules to prevent Long Match from launching any vehicle commercially for less than $58 million. This is likely to apply also to the Soviet Proton and other soviet vehicles.

Launch Manoeuvres
Target orbit (e.g. GSO) cannot, usually, be achieved in a single trajectory. Launch vehicles are "multi-staged" so propulsion is a series of distinct "burns".

In-plane manoeuvres:

  • changing orbit shape
  • raising or lowering apogee or perigee height
  • can be achieved with relatively low energy input (i.e. low fuel consumption)

Out-of-plane manoeuvres:

  • change of orbit inclination
  • rotating plane of orbit in space
  • requires relatively high energy input (i.e. high fuel consumption)

Next: Section 7 - Flight Plan & Maintaining Satellite In Orbit.


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