Several studies over the past few decades have recognized the need for advanced propulsion to explore the solar system. As early as the 1960s, Werner Von Braun and others recognized the need for a nuclear rocket for sending humans to Mars. The great distances, the intense radiation levels, and the physiological response to zero-gravity all supported the concept of using a nuclear rocket to decrease mission time. These same needs have been recognized in later studies, especially in the Space Exploration Initiative in 1989. One of the key questions that has arisen in later studies, however, is the need to utilize a nuclear fuel form that does not emit fission products into the exhaust stream. Unlike the Rover/NERVA programs in the 1960s, the rocket exhaust in a current day nuclear rocket should contain no radioactivity. We will investigate a series of coated fuel forms that will inhibit fission products and actinides from diffusing out into the surrounding coolant. A demonstration experiment will be designed that will allow fuels containing uranium-238 to be fissioned, heated to very high temperatures, and assessed for emission of any products.
