Leaving the Mun
The landing site was in the part of the Mun that always faces Kerbin (due to tidal locking), near to the terminator. This means that Kerbin is always visible in the sky.
But being near the easternmost terminator also meant that night would fall in a few hours. And because of the Mun's synchronous rotation, the night would last half its orbital period: 3.2 Kerbin days. This was too long a wait for the kerbonauts, so they would have to leave the Mun by night, which made the Lunar Module dependent on stored electrical power as the solar panels would be useless.
The night did offer some spectacular view, however:
It was now time to takeoff from the Mun and meet the Command Module in orbit.
With not much fuel left, the Lunar Module would have to wait two orbits to rendezvous with the Command Module.
Due to the damage to the Lunar Module's docking port, it could no longer dock with the CM. So once the ships got close enough to each other, the kerbonauts had to EVA to the Command Module. The Lunar Module would forever be left in lunar orbit.
An escape trajectory was setup with the Command Module's main engine that would take the ship into a very elongated eliptical orbit around Kerbin, with a periapsis low enough to get caught by the atmosphere:
And so with a final burn, the lunar mission was on its way back home.
Continue to Return to Kerbin ...