I'd say the reasoning for the specific positions is because of neighbouring allocations. For example, Arabsat were originally allocated 19°E in C-band, so Astra were slotted in at 19.2. Additionally, Kopernikus were allocated 28.5°E, which was taken over by Eutelsat, so Astra were assigned 28.2°E. The 28.2/28.5 split still exists today.Very interesting it is too, been reading a fair few articles up there, the ill fated launch of Astra 1K I didn't know about. That was an impressive bird 6 meters long.
Yeah I know Sky needed the capacity. My question was really concerned about what decides the orbital position, why did Astra decide upon 28.2e, seems very specific. As far as the UK is concerned 5w to 1e have to be better orbital positions as they satellite sits higher in the sky, so less chance of obstruction interfering with reception.
This is probably true. There's two "libration points" at 105°W and 74°E where an uncontrolled satellite in geosynchronous orbit will drift towards and eventually settle at.My uncle (professor of communication at a large UK university) says that gravity is not constant along the equator, and you in effect have troughs and peaks of gravity. It uses more fuel to keep the birds on the "peaks", so they would prefer them in the troughs where they have a tendency to stay.
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Thanks. I was taught that 75 East and 105 West were the gravity wells. Not just GEO either.This is probably true. There's two "libration points" at 105°W and 74°E where an uncontrolled satellite in geosynchronous orbit will drift towards and eventually settle at.