[ggm]

I always assumed it had an ability to relocate. I guess sustained movement in a 2y mission is hard, you have to budget for non-replaceables to make thrust work, ion thrusters consume stuff too.

I kind-of get it, that for a sufficiently timed orbit, it sees all places.. eventually. Being able to relocate means you can be where you want to be, without predictable periodicity.

[Cogito]

It's hard to explain without calling out to Kerbal Space Program, but it's really hard to figure out what you mean by 'able to relocate' in the context of orbital flight.

Your orbital period is determined by size of your orbit, and the difference between that and the earth's rotation causes your land track to precess. For most this means your land track will eventually be over every possible point. Raising or lowering your orbit will let you find a 'flyover' intercept in fewer orbits, but it will still take time to get there. Hard to do accurately and you normally want to keep that fuel around for boosting your orbit when it degrades due to atmospheric drag.

Other kinds of orbital manoeuvres could be used, but they are even more expensive and less likely to get you were you want to be (as long as you are in an inclination that passes over your desired target).

The main reason for this is that orbits are characterised (pretty much exactly) by your position/velocity pair. Every orbit your position and velocity will repeat, absent any external forces. Modelling any acceleration as instantaneous (which is pretty close) you can see that you can only ever directly change your velocity. Accelerate prograde and your orbit will be raised on the other side of your orbit; when you complete one of your new orbits you will be back in the exact same location, but with your new speed.

[ggm]

but it's really hard to figure out what you mean by 'able to relocate' in the context of orbital flight.

I mean make a change of plane in unpredictable ways. You can't just scoot sideways for no apparent reason, clearly orbit means what it says. But the point would be to make changes of orbit at cost, to get somewhere faster than waiting for the orbit you are in, to get there.

(height and speed over a point on the ground being assumed to be less important than actually being over it, when you want it to be over it)