The Nuclear Thermal Turbo Rocket - A Conceptual High-Performance Earth-to-Orbit Propulsion System

Abstract

A new propulsion concept called the Nuclear Thermal Turbo Rocket (NTTR) is proposed for Earth to Orbit applications. The NTTR utilizes a nuclear fission reactor to thermally heat hydrogen propellant into a rocket plenum. The rocket nozzles are located at the tips of a variable pitch thrust fan connected to the plenum by passages in the fan blades, and each nozzle is a linear aerospike on the trailing edge of the blade.The thrust fan is located in a duct such that the heated hydrogen propellant is combusted with ambientsourced oxygen to augment the rocket thrust. The fan is of variable pitch to provide maximum thrust for varying inlet velocity. The duct has a variable geometry inlet, able to provide appropriate mass flow and compression to the combustor throughout the trajectory, and a variable geometry outlet to provide appropriate nozzle area for maximum thrust. The rocket nozzles act as propellant injectors during the airbreathing portion and pure rockets during low atmospheric density portions, with the NTTR utilizing a single gas path from launch to orbital velocity. The propulsion concept is of high performance and is able to transport more than 50% mass fraction in a Single Stage to Orbit (SSTO) via an air-breathing rocket trajectory with intended complete reusability. Payload fractions of up to 19% are predicted (inert mass includes reactor radiation shielding) due to a mission average Specific Impulse (Isp) of 1,662 seconds. Nomenclature m = mass flow η c = compressor isentropic efficiency c p = constant pressure specific heat γ = ratio of specific heats T = absolute temperature P = absolute pressure M = Mach number MW th = Megawatt, thermal M f = Final Mass PR = Pressure Ratio (Outlet/Inlet) ΔV = change in velocity Φ = equivalence ratio k = reactivity coefficient Ψ = absolute temperature ratio β = oblique shock angle  = flow deflection angle

Thrust Augmentation and its Control Methods: Short Overview

“…At low Mach numbers, sufficient thrust will be produced in this NTTR. [9] Seung Hyung Nam(et.al, 2015) said nuclear propulsion is one of the best ways to conquer the hard environment of space. Due to its high thrust and efficiency, NTR is a choice for space missions to Mars.…”