Sharif Digital Repository

Unsymmetrical dimethyl hydrazine (UDMH) is a strong propellant, which due to its very good physical properties and high power of repellency has been utilized as a liquid fuel for fighter jet engines for so many years. There are different methods for production of this material. One of the more efficient ones which results in higher yields compared to others is the catalytic hydrogenation of Nitroso Dimethylamine (NDMA). In this work hydrogenation of NDMA to UDMH on a 5% Pd/C in aqueous solution of NDMA was studied experimentally. Experiments were carried out in a Semi-batch three phase STR reactor under constant pressure and temperature in the range of 40 to 70°C, pressures of up to 15 bar... 

A review of worldwide activities in liquid-fed pulsed plasma thruster (LPPT) is discussed. Pulsed plasma thruster are extensively recognized as one of the most promising electric space propulsion systems to perform propulsive tasks on micro- and nanosatellites, including cubesats, because they offer many advantages compared with other electric space propulsion systems. The low plasma exhaust velocity measured by a Langmuir probe showed that thrust is mainly produced by 0.3 μg mass ionized by the first trigger and a much greater quantity of propellant introduced by the main discharge remained neutral at low speed. Various propellant feeding and discharge initiation methods have been applied... 

Reaction thrusters (RTs) are used as an alternative to momentum exchange devices when disturbance torques exceed the control authority of momentum exchange devices. The reaction control system (RCS) can employ some rocket thrusters to provide attitude control during the thrusting or coast phase. Within the control loop, the RCS's target could be either achieving and keeping a certain attitude or controlling the rate of an attitude change. In the coast phase, some tasks such as preacceleration, settling of liquid propellant, damping of structural vibrations, providing a velocity increment to separate stages and payloads, and carrying out orbital and nonorbital maneuvers may be included in its...