Editing Zond program (section)

==Circumlunar missions==
{{main|Soyuz 7K-L1|Moon Race#Onward to the Moon}}

The missions [[Zond 4]] through [[Zond 8]] were test flights for the [[Soviet Moonshot]] during the [[Moon race]]. The [[Soyuz 7K-L1]] (also mentioned just as L1) spacecraft was used for the Moon-aimed missions, stripped down to make it possible to launch around the Moon from the Earth. They were launched on the [[Proton rocket]] which was just powerful enough to send the Zond on a [[free return trajectory]] around the Moon without going into lunar orbit (the same kind of path flown by [[Apollo 13]] in its emergency abort). With minor modification, Zond was capable of carrying two [[cosmonauts]].

In the beginning, there were serious reliability problems with both the new Proton rocket and the similarly new Soyuz spacecraft, but the test flights pressed ahead with some glitches. The majority of test flights from 1967 to 1970 ([[Zond 4]] to [[Zond 8]]) showed problems during re-entry.

The Zond spacecraft made only uncrewed automatic flights. Four of these suffered malfunctions that would have injured or killed any crew. Instrumentation flown on these missions gathered data on [[micrometeor]] flux, solar and [[cosmic ray]]s, [[magnetic field]]s, radio emissions, and [[solar wind]]. Many photographs were taken and biological payloads were also flown.