Zond (KSP 1.8.1/RSS/RO/Principia)

The Zond program (1967-1970) was an attempt by the Soviet Union to beat America to the Moon by sending two cosmonauts in a modified Soyuz spacecraft on a circumlunar flight. Despite the successful return of several spacecraft, including a number of small animals on Zond 5, most flights experienced failures that would have killed any human crew and the program was cancelled before any manned flights could take place.

That however, is entirely no fun. Instead, I explore an alternate timeline where a crewed circumlunar flight actually happened.