The repeated thrust applications at apoapsis would raise periapsis from inside to outside the stationary orbit.

重复在远心点施以推力，心点由轨道内提轨道外。

Now thrust could be generated (for “free” again) at periapsis, progressively increasing the altitude of apoapsis.

这时可以「免费」在心点产生推力，渐渐远心点的高度提。