>>11846110Space tugs are also usefull for when you need to ship payload in both directions.
Let's take GEO as an example:
One needs to accellerate new satellites up to GEO and de-orbit old ones.
The mass ratio between up and down is about 1:1.
An ion thruster powered space tug could take payloads + xenon reaction mass from LEO up to GEO and take GEO satellites down to LEO to de-orbit.
The only question is if the power source of the space tug shall be solar or nuclear.
It could also perform refueling missions on older satellites in GEO, given that these satellites have the required conections to do so.
A standard to conect satellites would be required to do so.
(except to de-orbit, a net and a teather would be sufficient here)
