Annotation: The Ukrainian companies Yuzhnoye SDO and SE PA YMZ supply VG143 main engine assembly for Vega LV AVUM upper stage, which is a one-chamber LRE of 250 kg thrust with five ignitions in flight. By the present, 11 successful launches of Vega LV have been made. In the process of flight operation, there were no critical comments on engines operation. This LRE has a combination of attractive characteristics, such as high specific pulse, low mass, multiple ignitions in flight, high reliability confirmed by good results of flight test of the prototype engines. The reserve of this engine from the viewpoint of further modernization is far from being exhausted. Enhancing the capabilities of payload injection by launch vehicles into various orbits of artificial Earth satellites is the main task for the developers of ILV as a whole and for the developers of separate assemblies and systems, such as LRE being part of ILV. With consideration for the experience of prototype engines testing, we should note the following ways of main engine assembly modernization: – increasing the specific pulse due to the increase of nozzle expansion ratio; – decreasing the volume of internal manifolds and mass of chamber; – increasing the operation time; – increasing the ignitions number; – increasing the duration of pauses between ignitions and orbital functioning time. Increasing the thrust and specific pulse of Vega LV VG143 main engine assembly and AVUM stage takes place due to the use of pneumopump propellant feeding system instead of standard pressure feeding. Besides, the information is presented on RD859, RD864, RD866 and RD869 prototype engines, the data on their basic characteristics, testing and operation. The below information is of interest to LRE and LV developers.

Annotation: One of the important directions in the development of Yuzhnoye SDO liquid rocket engines is creation of the engines for launch vehicle upper stages, boosters, space tugs and takeoff-and-landing vehicles. The article presents an overview of Yuzhnoye SDO – developed liquid rocket engines, their basic characteristics, distinctive features and the current status of development and operation. The article presents the information on the following engines: RD858 and RD859 operating on storable propellants, for lunar takeoff-and-landing Block E module; RD809M and RD809K operating on liquid oxygen + kerosene created on the basis of RD8 serial control engine of Zenit launch vehicle second stage. In this case, RD809M engine is RD8 version with tight integration and RD809K engine is its one-chamber version; RD805 engine operating on liquid oxygen + kerosene created on the basis of combustion chamber of RD8 serial control engine of Zenit launch vehicle second stage.; RD835 engine operating on liquid oxygen + kerosene created for the second stages of launch vehicles of Mayak type; the engines and propulsion systems operating on storable propellants, such as RD861K (main engine of Cyclone-4 third stage and Cyclone-4M launch vehicle second stage), DU802 (liquid propulsion system of Krechet autonomous space tug of conversion Dnepr launch vehicle), RD840 (apogee liquid rocket engine of liquid propulsion system of geostationary communication satellite bus), VG143 (main engine assembly of the fourth stage of European Vega launch vehicle), RD864 and RD869 (main engines of Dnepr launch vehicle upper stages). The information presented in the article is of interest to liquid rocket engines and launch vehicles developers.