Approximately how much fuel would be necessary to place a satellite into geosynchronous orbit?
That would give the amount of work just to raise it to the right altitude (i.e., to supply the necessary change in gravitational potential energy). But you'd need more energy to make it orbit circularly. By the virial theorem, the kinetic energy you'd have to add is equal to half of the final potential energy.Originally posted by Inquiring_Mike
Okay... Say the mass is 1000kg... Would using the W(total) = GMm (1/r - 1/r2) equation give the amount of energy needed to place the satellite into orbit...
Atmospheric drag is totally insignificant in GEO, even if your sat is built like a parachute. In LEO, you need to re-boost occasionally to counter drag, but in GEO, the only fuel you'd need would be for stationkeeping (keeping it in the right position in the sky). That's usually up to a few tens of m/s per year, depending on the specific placement of the orbit.Originally posted by Inquiring_Mike
Then would the satellite need more energy to keep it in orbit?
This is a correct statement. However, a convient rule of thumb is that between 1 - 2 % of the total mass of the launch system [satellite, launch vehincle, propellant] can be plaaced in orbit.That depends on (among other things) the specific impulse of the fuel, and the mass of the satelite.