Radioisotope Thermoelectric Generators, or RTGs, provide electricity to the atmosphere by converting heat generated by the decomposition of plutonium-238 (Pu-238) gas into electricity using devices called thermocouples. Since they do not have moving parts that can be damaged or worn out, RTGs have historically been considered the most reliable electrical power. Thermocouples have been used in RTGs for a combined period of more than 300 years, and not a single thermocouple has stopped producing energy. The purpose of this research is to study the radioisotope energy generation and power systems. Study power generation capacity and efficiency when compared to nuclear fission and solar arrays. To learn about Electric Ion propulsion drive and its power consumption. To get the energy needed for future Manned and unmanned space missions or interplanetary space explorations. Merits and demerits of Radioisotope Power Systems in the context of power supplying capacity and electric power needed for future explorations. It is found that RPS and RTG are capable of generating energy for a long time but cannot generate high levels of energy i.e. RTG generates only 100-400 KW of electrical power whereas Nuclear fission generates fairly high levels of energy by splitting neutron from atoms. It is expected that energy needed for manned space missions are in tens of megawatts. On comparing Radioisotope Power Systems (RPS) with the nuclear fission and solar arrays power generation, It seems that having Nuclear reactor with the spacecraft could be the first step towards the Megawatt energy generation for Space explorations

Keywords : Thermoelectric Generation, Radioisotope, Power Systems, Thermal Energy, Nuclear Fuel, Alpha Particles, Nuclear fission, solar arrays, Electric Ion Propulsion Drive