Question about low-thrust propulsion

[RulerOfNothing]

I have another astrodynamics question, this time regarding low-thrust propulsion systems such as ion engines. Basically, if an orbiting spacecraft maintains the same orientation, a low-thrust propulsion system cannot be used, since the momentum change on one side of the orbit will be cancelled out by the momentum change on the other side of the orbit. My question is: what is the most propellent-efficient method of causing momentum changes? Is it:

a) only firing the engine on one side of the orbit,

somehow rotating the spacecraft so that the momentum change is always in the same direction as the orbital velocity or

c) something else altogether?

[Rocket Surgeon]

What is it you're trying to achieve, even?

[Richy]

As far as I know, they use your option .

For the 'somehow' you can use a reaction control system driven with rocketfuel, or gyroscopes like the use on the ISS.

That way they achieve the often mentioned 'spiraling-out' of an orbit.

[RulerOfNothing]

As far as I know, they use your option .

For the 'somehow' you can use a reaction control system driven with rocketfuel, or gyroscopes like the use on the ISS.

That way they achieve the often mentioned 'spiraling-out' of an orbit.

Ah, right. Thanks for the answer Richy.