Zond 4

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Zond 4
Zond L1 drawing.png
Names Soyuz 7K-L1 s/n 6
Mission type Lunar flyby
Spacecraft test
Operator OKB-1
COSPAR ID 1968-013A
SATCAT no. 03134
Spacecraft properties
Bus Soyuz 7K-L1
Manufacturer OKB-1
Launch mass 5,140 kilograms (11,330 lb)
Dimensions 4.5 m x 2.2 m x 2.72 m
Start of mission
Launch date 2 March 1968, 18:29:23 UTC
Rocket Proton-K/D
Launch site Baikonur 81/6
End of mission
Disposal deorbited/destroyed
Decay date March 7, 1968 (1968-03-07)
Landing site Gulf of Guinea
Orbital parameters
Reference system Geocentric
Regime Low Earth
Perigee 192 kilometres (119 mi)
Apogee 205 kilometres (127 mi)
Inclination 51.53°
Period 88.41 minutes

Zond 4, part of the Soviet Zond program and an unmanned version of Soyuz 7K-L1 manned Moon-flyby spacecraft, was one of the first Soviet experiments towards manned circumlunar spaceflight. It was launched to test the spaceworthiness of the new capsule and to gather data about flights in circumterrestrial space. It was the first Soviet spacecraft to possess a computer, the 34 kg Argon 11.[1]

The spacecraft was successfully launched into a 354,000 km apogee orbit 180 degrees away from the Moon, It was launched away from the Moon probably to avoid trajectory complications with lunar gravity. However on re-entry the L1's guidance system failed. It hit the atmosphere precisely at the calculated time, but was not guided to generate lift and fly out of the atmosphere again. A ballistic re-entry would mean no recovery on Soviet soil, so the APO destruct system automatically blew up the capsule at 10 to 15 km altitude, 180–200 km off the African coast at Guinea.


  1. ^ Huntress; Marov (2011). Soviet Robots in the Solar System: Mission Technologies and Discoveries. p. 172. 

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