Block E (rocket)

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Block E
Block E supported in a shop
Block E internal diagram
Role Propulsion Unit
Engines RD-858 and RD-859
Height 1720 mm
Diameter 2380 mm
Empty Mass 525 kg
Fueled Mass 2,950 kg

Block E is the propulsion unit of Soviet lunar module LK, developed in 1960s by Yuzhnoye Design Bureau as a part of the manned lunar landing program. Block E was designed to soft land LK on the surface of the Moon after orbital velocity was cancelled by Block D and later to launch LK to the Moon orbit for the rendezvous with Soyuz 7K-LOK.[1][2]

Block E used RD-858, which has one nozzle and is deeply throttleable (from 2050 kg to 858 kg of thrust),[3] as the primary engine. The backup engine was RD-859, which has two nozzles. Engines were equipped with clam-shell doors to prevent damaging it while staying on the surface of the Moon. There were four additional vernier engines placed between main and backup engine nozzles.


  1. ^ "LK spacecraft and Block E". Archived from the original on 2013-12-30. Retrieved 2013-12-15.
  2. ^ "Liquid propellant propulsion systems, Yuzhnoe Design Bureau". Retrieved 2014-07-10.
  3. ^ "RD-858". Archived from the original on 2016-03-26. Retrieved 2016-03-18.