Reply to thread

Message: <blockquote data-quote="Analoguesat" data-source="post: 1084441" data-attributes="member: 176362">Well MEV1 has to move both its own mass plus the dead weight of I-901, plus kill the accumulated inclination plus wait for the right time to slide back down towards 27.5W dodging all the other satellites (both operational & derelict) that are on or around the geostationary arc. Its thrusters are electric grid & the pushing power of those is tiny compared to chemical hydrazine thrusters.9 times out of 10 the limiting factor in a satellites useful life as a tv broadcast bird is depletion of station keeping fuel. There is a fine trade off between adding extra fuel before launch for longer station keeping - which costs more to launch . Or tanking less fuel for a cheaper launch but reducing the useful none inclined life.Its fairly rare for a bird to have to be retired due to electronics failure. It does happen & itseems more breakdowns have happened in recent years but thats probably just due to the higher number of tv satellites being launched compared to 10-15 years ago. In the case of I-901 there will be contingency plans in place to turn off transponders if the solar sails have degraded.. And lets be honest 27.5W isnt exactly the busiest slot on the European arc. There wouldnt be much lost if a couple of tps had to be turned off at some pointAs I said earlier there will be a LOT of testing checking and rechecking of everything before the MEV1 thruters are lit up in anger. Northrop has to prove to Intelsat and future custromers the combined stack is stable and isnt going to do anything unexpected - which will be why I-901 ws punted up to graveyard orbit for this to be tested. If anything does go wrong and debris is created the birds are safely out of the way of the operational sats. In a few years time this will be routine and the MEV's will do their stuff directly onto satellites whilst they are operational on the orbital geosat arc.Intelsat must be confident this is going to work - MEV2 is already booked for a mission on another Intelsat bird (identity not released yet)</blockquote>

Verification