This last one is the one that makes the most sense to me. It requires the least extra engineering on delivery vehicles and could work for most larger satellites that may need to be able to maneuver on orbit anyway. Vehicles delivering cube sats might need a de-orbiting booster on their stage though. In that case it probably makes most sense to build the final stage with a little extra dv and just burn retrograde after delivery.
There will have to be some cost trade-offs for the big GEO sats. What is the extra fuel worth to the satellite owner? Or expedited delivery to the target orbit? Is it worth the cost of sending a separate little deorbit tug up for the 2nd stage? Or a separate refuelling mission somewhere down the line?
This last one is the one that makes the most sense to me. It requires the least extra engineering on delivery vehicles and could work for most larger satellites that may need to be able to maneuver on orbit anyway. Vehicles delivering cube sats might need a de-orbiting booster on their stage though. In that case it probably makes most sense to build the final stage with a little extra dv and just burn retrograde after delivery.
There will have to be some cost trade-offs for the big GEO sats. What is the extra fuel worth to the satellite owner? Or expedited delivery to the target orbit? Is it worth the cost of sending a separate little deorbit tug up for the 2nd stage? Or a separate refuelling mission somewhere down the line?
Well one of the options was to park them in graveyard orbits which for geo stationary orbits is probably the most effective