Space exploration is the present inevitable challenge for researchers. Various theoretical propulsion concepts have been evolved over the past years for space missions. Their potential remains as a key factor for the spacecraft to travel deeper into space in a shorter mission duration. The propulsion concept UNIT is an integrated nuclear propulsion technique that provides high entry, descent and landing (EDL) performance in such short duration to conquer other galaxies. This paper describes the theoretical approach of the UNIT propulsion system in detail. UNIT produces the highest energy possible by consuming nuclear fuel and possess the highest potential that opens new opportunities for space exploration. The principle is that the neutrons from the fusion are deliberately allowed to induce fission. It uses National Ignition Facility's laser beam for inertial confinement fusion followed by utilizing the power from tubular solid fuel cell. Thus, the net thrust is produced from the expansion of the combined plasma of the nuclear fusion and nuclear fission reactions through the nozzle.