Block E (rocket)

Block E

Description
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.

References

1. "LK spacecraft and Block E". Russianspaceweb.com. Retrieved 2013-12-15.
2. "Liquid propellant propulsion systems, Yuzhnoe Design Bureau". yuzhnoe.com. Retrieved 2014-07-10.
3. "RD-858". Astronautix.com. Retrieved 2016-03-18.