of 239Pu. It has a very high cross section for fission, and is destroyed relatively quickly in a nuclear reactor. Another report claims that 242mAm can sustain a chain reaction even as a thin film, and could be used for a novel type of nuclear rocket. Since the thermal absorption cross section of 242mAm is very high, the best way to obtain 242mAm is by the capture of fast or epithermal neutrons in Americium-241 irradiated in a fast reactor. However, fast spectrum reactors are not readily available. Detailed analysis of 242mAm production in existing PWRs was provided in. Proliferation resistance of 242mAm was reported by Karlsruhe Institute of Technology 2008 study. In 2000 Carlo Rubbia at CERN further extended the work by Ronen and Chapline on fission-fragment rocket using 242mAm as a fuel. Project 242 based on Rubbia design studied a concept of 242mAm based Thin-Film Fission Fragment Heated NTR by using direct conversion of the kinetic energy of fission fragments into increasing of enthalpy of a propellant gas. Project 242 studied the application of this propulsion system to a crewed mission to Mars. Preliminary results were very satisfactory and it has been observed that a propulsion system with these characteristics could make the mission feasible. Another study focused on production of 242mAm in conventional thermal nuclear reactors. See also Fission fragment reactor Pulsed nuclear thermal rocket Nuclear salt-water rocket References Americium Nuclear spacecraft propulsion