| In this dissertation, the development of the two-stage micro pulsed plasma thruster (muPPT) is described. This development followed from a research effort aimed at overcoming crippling performance limitations of the conventional PPT. Several fundamental causes of this performance shortfall were identified, and attempts to overcome them were uniformly unsuccessful. Furthermore, a trade study of other micropropulsion systems suggested that even an improved conventional PPT would find little use.; However, previous work had suggested that the conventional PPT could be greatly reduced in size and complexity, and the same mission-specific trade study indicated that a micro PPT would be quite useful even if of limited performance. Previous testbed muPPTs, operating in an actively triggered mode, were laboratory curiosities of little practical value. The two-stage muPPT, with triggering performed in a separate stage, passively coupled to the main discharge, greatly simplifies the device while allowing a much larger propellant loadout and total propulsive impulse. A complete three-axis thruster module with 25 N-s of impulse along each axis, can be constructed from off-the-shelf components with a total mass of less than one kilogram.; The two-stage muPPT was developed and extensively tested, proving to be a robust, reliable system with sufficient performance for near-term missions. Several avenues for further improvement were identified. A flight muPPT has been constructed, representing the current state of the art in this area, and will fly on the USAF FalconSat-3 spacecraft in early 2007. |
