The trends today are toward smaller satellites with increased capability. These two trends place enormous demands on the technology used to power such space systems. Typical power sources are nuclear, photovoltaic, and chemical. As the power available on a typical satellite decreases, the use of long pulsed power sources becomes more attractive. Technologies such as electrochemical capacitors, pulsed batteries and flywheels offer the possibility of employing high power subsystems for limited times without undue burden on the spacecraft power train. The state of the art in each of the pulsed storage devices is discussed and preliminary experiments described which use an electrochemical power source to power a spacecraft propulsion unit such as an arc-jet or Hall effect thruster.