FIELD: space engineering. SUBSTANCE: invention relates to space propulsion systems, mainly to cruise electric rocket engine plants of space vehicles and complexes. In proposed electric rocket engine plant containing solar or nuclear power source, electric current converter, engine module and bus made of conducting material depending on working temperature and connecting output of electric power source with input of electric current converter, blacking coating is applied to outer surface of bus and each bus is made in form of electric conductor of rectangular section areas S, sq.m., of section being chosen from equation S = {N[ργp]1/2}/{U[T4fδd]1/2}, where 
, d = 0,6T4-0,8T3/α+0,8ToT3+0,2T4
o
, ρ, (Ohm. m) is specific resistance of bus material; N (W) is electric power transmitted along heat radiating bus from electric power source to electric current converter; To(K) (K) is temperature of by bus t no current, T(K) is working temperature of bus; δ (kg/m3) kg/cu.m is density of bus material; α (K-1) is temperature coefficient of bus material electric resistance; γ (kg/Wt) (kg/W) is specific mass of electric power source, f≤1, is coefficient; V (V) is working voltage of electric power source. Ratio of thickness h to width b of bus outer surface is chosen from equation h/b = [A+(A2-S)1/2]2/S, where A=A = {N[δρd]1/2}/{4Uσε[fT4pγ]1/2}, σ, (Wt/m2K4)) is Stefan-Biltzmann constant, ε is emissivity factor of bus radiating surface. Aluminum or beryllium is used as material for bus operating at temperature from 300 K to 600 K, copper, molybdenum or niobium is used at temperatures from 600 K to 800 K, molybdenum is used at temperatures from 800 K to 1100 K and lithium filled niobium tube is used at temperatures from 1100 to 2000 K. Invention improves efficiency of electric rocket engine plants owing to optimization of energy transmission from power source to electric rocket engines along buses featuring enlarged range of working voltages and power transmission range. EFFECT: improved efficiency of electric rocket engine installations. 5 cl, 2 dwg
