RD-843

The RD-843 is a Ukrainian single nozzle liquid propellant rocket engine. It burns a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide (N₂O₄) oxidizer. It is pressure-fed. It is rated for up to 5 restarts, and can gimbal up to 10 degrees in each direction.^[2]

RD-843 (РД-843 / MEA)

Country of origin	Ukraine
First flight	2012-02-13
Designer	Yuzhnoye Design Bureau
Manufacturer	Yuzhmash
Application	Upper stage
Associated LV	Vega, Vega C
Predecessor	RD-869
Status	In production
Liquid-fuel engine
Propellant	N2O4 / UDMH
Mixture ratio	2.0
Cycle	Pressure-fed
Configuration
Chamber	1
Performance
Thrust, vacuum	2.452 kN (551 lbf)
Chamber pressure	2.04 MPa (296 psi)
Specific impulse, vacuum	AVUM: 314.6 s (3.085 km/s) AVUM+: 315.8 s (3.097 km/s)
Burn time	AVUM: Up to 612.5 seconds AVUM+: Up to 924.8 seconds[a]
Restarts	Up to 5
Gimbal range	±10°
Dimensions
Dry mass	15.93 kg (35.1 lb)
Used in
AVUM, AVUM+
References
References	[1][2][3][4]

It was developed by Yuzhnoye Design Bureau for Avio and is manufactured by Yuzhmash. It uses the RD-869 thrust chamber, the old Soviet ICBM SS-18 final stage engine from which it is evolved, and which was also designed by Yuzhnoye. The RD-843 ground test campaign included 74 tests, 140 ignitions, reaching a total of 8,201 seconds, which is approximately 12 service lives on 4 engines. As of June 2020 it has been successfully used on 14 orbital launches.^[5]

The Vega and Vega C uses it as the main engine on its AVUM (Attitude & Vernier Upper Module) fourth stage which it calls the MEA (short for Main Engine AVUM).^[6]

See also

• AVUM - The upper stage of the Vega rocket that uses the RD-843 as its main engine.
• Vega - The ESA small rocket that uses AVUM.
• Yuzhnoe Design Bureau - The RD-843 designer bureau.
• Yuzhmash - A multi-product machine-building company that's closely related to Yuzhnoe and manufactures the RD-843.

Notes

1. Engine can burn up to 612.5 seconds per burn. Maximum cumulative burn time of 924.8 seconds.