Soyuz 7K-LOK

Mission Profile

Soyuz 7K-LOK (Lunar Orbital Craft) was the Soviet crewed spacecraft designed to carry two cosmonauts from Earth to lunar orbit and back as part of the N1-L3 lunar landing program, analogous to the American Apollo Command and Service Module. Larger and more capable than the Soyuz 7K-OK, the LOK featured an extended service module with high-thrust main engine for trans-lunar injection and lunar orbit insertion, a docking system for the LK lander, and a separate orbital module for crew transfer. Two LOK-derived spacecraft were tested unmanned in Earth orbit as Soyuz 7K-L1 (Zond) on circumlunar trajectories. The program was cancelled after the N1 rocket's four consecutive failures made a Soviet crewed lunar landing impossible to achieve before the program's abandonment in 1974.