|Country of origin||Ukraine|
|Designer||Yuzhnoye Design Bureau|
4 / UDMH
|Thrust (vac.)||2,452 newtons (551 lbf)|
|Chamber pressure||2.04 MPa (296 psi)|
|Isp (vac.)||315.5 seconds|
|Burn time||up to 667s|
|Dry weight||15.93 kilograms (35.1 lb)|
The RD-843 is a Ukrainian single nozzle liquid propellant rocket engine burning pressure-fed UDMH and nitrogen tetroxide. It is rated for up to 5 restarts, and can gimbal up to 10 degrees in each direction.
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 Satan 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 8201 s, which is approximately 12 service lives on 4 engines. As of June 2020 it has been successfully used on 14 orbital launches.