Okay, since sometimes there's conflicting information on Russian stuff, I checked with my two favorite websites for this stuff: astronautix.com and russianspaceweb.com. The problem is complicated by the fact that "Zond" actually describes more spacecraft than you might think, thanks to the Soviet tendency to obscure their intentions in case of failure. The one's we're actually interested in are Zonds 4-8. These were Soyuz 7K-L1 spacecraft launched by Proton rockets. There were additional 7K-L1 spacecraft which either did not reach orbit (and which consequently received no descriptor at all) and ones used for other testing in Earth orbit (which received Cosmos designators).<br /><br />Zond 4 - self-destructed<br />The guidance system failed, making the double-skip reentry impossible. Capsule could still acheive a theoretically-survivable ballistic descent, but it would be outside the Soviet Union. Automated self-destruct package had been armed, and the vehicle destroyed itself over the Gulf of Guinea at an altitude of 12 km when the computer detected that the intended mission would not be achieved. After some dispute, it was decided that if there was a repeat of this circumstance, the vehicle would be allowed to reenter for an attempted recovery by Soviet naval vessels.<br /><br />Zond 5 - splashdown in the Indian Ocean<br />The star tracker failed and the mission controllers had to revert to using the less accurate earth tracker. This made a double-skip reentry impossible. The self-destruct package was not armed, and the vehicle survived a 20-G reentry, after which it was recovered in the Indian Ocean. Given how long it was at 20Gs, this would probably not have been survivable.<br /><br />Zond 6 - depressurized and then crashed<br />After a series of problems, Zond 6 depressurized during the cruise back to Earth. It did, however, manage the first successful double-skip reentry. But when it returned, a parachute malfunction caused it to crash violently into Kazakh <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>