See the regular Hohmann transfer [0]. Adding Δv at one point causes the orbit to become elliptic and will still pass through the same altitude, the yellow line

See the regular Hohmann transfer [0]. Adding Δv at one point causes the orbit to become elliptic and will still pass through the same altitude, the yellow line in the picture. To increase the lower altitude, also called the periapsis, you need to add Δv higher up, which is the opposing side of the orbit for 100% efficiency and through that you create the circular red line. [0]: https://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Hohmann_transfer_orbit.svg/440px-Hohmann_transfer_orbit.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Ho...