PPT Development for Nanosatellite Applications: Experimental Results
In this paper, the design and performances of a pulsed plasma thruster (PPT) for nanosatellite applications will be presented. The breadboard model PPT presented in this paper will be a part of six PPTs propulsion system designed to provide attitude and translational control for a 20-kg nanosatellite for a total delta-V of 40 m/s. The thruster performances have been characterized in terms of electrical parameters, mass bit, impulse bit, and specific impulse. The thruster was found to be compliant with the mission requirement. Moreover, preliminary electromagnetic noise interference measurements have been performed. The spark plug discharge was found to be the main source of noise as already found by previous authors. From the collected data, it can be inferred that the noise is mostly radiated.
An impulsive thrust balance for applications of micro-pulsed plasma thrusters
This paper describes the design and testing of a direct torsional impulsive thrust balance. The design philosophy allows the balance to measure impulse bits (Ibit) in the range of 20–120 µN s typical of pulsed plasma thrusters (PPTs) for pico- and nano-satellites. The uncertainty in the Ibit measurement is quantified to be about 8.8%, smaller than the typical values of this kind of balance (between 12% and 15%). This has been possible due to an in-depth analysis of all the possible sources of disturbance, which allows the choice of the most suitable measurement and estimation methods to minimize the errors. The balance has successfully been used for testing two PPTs with different propellant feeding system, nominal energy, mass and delivered impulse bits.
A new power measuring circuit using a bridge-connected magnetic circuit and another magnetic core
The authors describe the operating characteristics of an oscillating circuit using a bridge-connected magnetic circuit and another magnetic core. A square-shape output voltage is obtained in the oscillating circuit. The pulsewidth in positive and negative half cycles of output voltage changes with the current of the U-form core windings and with the signal voltage applied to the exciting windings. The mean value of the output voltage varies in proportion to the product of the current and the signal voltage. Utilizing this feature, an application of the oscillating circuit to a novel power measuring circuit of simple construction is presented. >