Nuclear fuels in space rockets

There are three different types of rocket engines; solid propelled rockets, liquid propelled rockets and nuclear rockets. Nuclear rockets work by routing an appropriate gas through a nuclear rector. The reactor is at high temperature. Gas expands as it leaves the nozzle, producing a high amount of thrust. Nuclear rockets don't need an oxidizer and they require much less fuel per pound of payload then liquid or solid fuel rockets. This allows a vehicle using a nuclear rocket to be more versatile than one which uses chemical rockets. Disadvantages of nuclear rocket include radiation effects by the nuclear reactor, and the high weight of the engine assembly. 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 human 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. One of the aspects of the initiative is to develop a nuclear propulsion system for unmanned exploration of solar system. Heat produced from neutron-induced splitting (fission) of /sup 235/U, /sup 239/Pu or /sup 233/U. Heat converted to electricity, or used directly to heat a propellant.