Catching up to the Lunar Module
Edited Apollo 17 image (taken from the ascending Lunar Module) of the Command Service Module in a lower lunar orbit than the Lunar Module. This was to let the CSM catch up with the Lunar Module (lower orbits are faster than higher orbits which leads to the weird (but true!) situation in orbital mechanics: if you want to go faster around a planet (or moon), you need to brake).
Catching up to the Lunar Module
Edited Apollo 17 image (taken from the ascending Lunar Module) of the Command Service Module in a lower lunar orbit than the Lunar Module. This was to let the CSM catch up with the Lunar Module (lower orbits are faster than higher orbits which leads to the weird (but true!) situation in orbital mechanics: if you want to go faster around a planet (or moon), you need to brake).