A lunar module is a lunar lander designed to allow astronauts to travel between a spacecraft in lunar orbit and the lunar surface. As of 2020, Apollo Lunar Module was the only lunar module ever used in human spaceflight. Being carried atop a Saturn V launch vehicle, the Apollo LM was used for the Apollo program from 1969 to 1972.
The LK module was developed in the 1960s as a part of several Soviet crewed lunar programs. Several LK modules were flown without crew in Earth orbit, but no LK ever reached the Moon. The development of the N1 launch vehicle required for the lunar flight suffered setbacks (including several launch failures), and the first Moon landings were achieved by US astronauts. As a result, both the N1 and the LK programs were canceled without any further development.