<p>Thermionic (TI) power conversion is a promising technology first investigated for power conversion in the 1960&rsquo;s, and of renewed interest due to modern advances in nanotechnology, MEMS, materials and manufacturing. Benefits include high conversion efficiency (20%), static operation with no moving parts and the potential for high reliability, greatly reduced plant complexity, and the potential for low Design, Development. Test and Evaluation (DDT&amp;E) costs. Thermionic emission, credited to Edison in 1880, forms the basis of vacuum tubes and much of 20th century electronics. Heat can be converted into electricity when electrons emitted from a hot surface are collected across a small gap. For example, two &ldquo;small&rdquo; (6 kWe) Thermionic Space Reactors were flown by the USSR in 1987-88 for ocean radar reconnaissance. Higher powered Nuclear-Thermionic power systems driving Electric Propulsion (Q-thruster, VASIMR, etc.) may offer the breakthrough necessary for human Mars missions of &lt; 1 yr round trip.</p><p>This project targets one of the most critical barriers to human deep space exploration &ndash; the means to efficiently power and rapidly propel human missions to Mars and beyond.&nbsp; The project will explore the implementation of a high efficiency &ldquo;Solid-State&rdquo; Thermionic-based nuclear fission power systems to serve Electric Propulsion systems such as Q-thrusters, VASIMR, Hall, or other approaches.&nbsp; A Solid-State approach centered around advanced Thermionic power converters would combine the high efficiency of traditional dynamic power conversion (Rankine, Brayton, Stirling) with the simplicity of a static converter with no moving parts.&nbsp; The resulting system could enable Human Mars missions of &lt; 1 year round trip by affording a system of megawatt power, low specific mass (&lt;10 kg/kWe), greatly reduced plant complexity, and associated savings in development cost.&nbsp;&nbsp; This project provides the initial foundation and confidence for high efficiency solid-state power converters, and early definition of enabled human exploration systems and missions (ex. Megawatt Electric Propulsion, Moon/Mars Surface Power).&nbsp; Subsequent converter development will improve readiness and lifetime, leading to &ldquo;flight ready&rdquo; articles.&nbsp; An intermediate NASA infusion step would demonstrate kilowatt-class nuclear power systems applicable to Moon or Mars surface.&nbsp; Human vehicle system development would then integrate these converters with DOE nuclear reactor technology, NASA balance of plant (ex. radiators, PMAD), and electric propulsion (ex. Q-thrusters, VASIMR, Hall thrusters) to develop an &ldquo;ultimate&rdquo; NASA application of a Human Mars Megawatt-class Nuclear Electric Propulsion vehicle and mission.&nbsp; Terrestrial applications would be informed/infused resulting in high efficiency power systems with greatly reduced complexity and cost.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p>