LOX/CH4 and LOX/LH2 Heavy Launch Vehicle Comparison

Abstract

LOX/CH4 is often regarded as a new promising propellant. As a light hydrocarbon the advantage of methane compared to RP-1 is its worldwide availability, higher ISP. From a propulsion point of view methane leads to low soot combustion and a good capability to cool the combustion chamber without the risk of cracking and deposit. Compared to liquid Hydrogen fuel despite its lower IPS, methane presents a higher density and a high vapor pressure.The topic of this paper is to present a trade-off design of two kinds of heavy launch vehicle able to bring to GTO a 6t class payload. Each of three stages of the launcher burn either LOX/LH2 or LOX/CH4. The key factors for comparison are the GLOW, the propellant mass and engines thrust for each stage. NomenclatureFs = Delivered thrust at ground level (kN) Fv = Delivered thrust at sea level (kN) ISPs = Specific impulse at ground level (s) ISPv = Specific impulse at sea level (s) Me = Propellant mass (T) Pc = Chamber pressure (bar)