 Leasat F4 was subsequently powered down and moved to a graveyard orbit with a large amount of station keeping fuel in reserve.This was fortuitous; when another satellite suffered a loss of its fuel ten years later, Hughes engineers pioneered the use of alternative propellants with Leasat F4.Long after its primary mission had failed, F4 was powered back on to test whether a satellite could be kept on station using nonvolatile propellants.