A new fission powered space power and propulsion system based on using a non-moving fissile gas is proposed. The main innovation in the proposed fission based propulsion system is the use of well-established fusion plasma confinement and compression method to achieve supercritical condition in a highly subcritical fissile gas. In particular, electromagnetic induced shock wave compaction and gas dynamic trap techniques are merged to bring a relatively small volume (~ 1 m3) of a fissile (235U, 233U, or 239Pu) compound gas to prompt supercriticality condition, thereby, releasing an intense pulse fission power. A magnetic field compaction scheme is designed to directly convert the fission energy to electricity. The specific energy of the proposed nuclear electric system for megawatt level power operation is well above 1 KWe/Kg. An alternative direct propulsion system is designed based on using a merger between Magnetized Target Fusion (MTF) and hydrodynamic confinement techniques to achieve long duration (~ 100 to 1000 ms) criticality and ultrahigh burnup in a fissile gas. The MTF technique induces large pressure ratio (~ 10) adiabatic compaction of fissile gas by rapid collapsing of a cylindrical layer of a low neutron absorbing metal (Al or Zr). Hydrodynamic confinement in a leaky reversed mirror configuration is used to contain and direct the fission plasma through a nozzle, thereby, generating intense thrust (~ 100?s of Klb) at specific impulse levels in excess of 2000 seconds. POTENTIAL COMMERCIAL APPLICATIONS An open magnetic configuration scheme to drive fission power system utilizes fissile materials in highly subcritical condition. The low nuclear material inventory combined with the active nature of the criticality inducing process is a unique feature of the proposed space nuclear power and propulsion system. The exceptional simplicity and safety of the proposed concept provides an unlimited potential for a wide range of space power and propulsion applications. Furthermore, the success of the proposed project will potentially lead to terrestrial applications including commercial nuclear power generation at a very competitive cost with improved safety features
