System optimization of ablative pulsed plasma thrusters for stationkeeping

We present a realistic and easy-to-apply model for the system optimization of ablative pulsed plasma propulsion for stationkeeping missions. The model yields the characteristics of the propulsion module(s) that lead to minimum propulsion system mass for given mission specifications. We show that using an empirical relation for mass production, an expression relating the optimal (minimum) propulsion system mass to the thruster's most important scaling parameter E/I (the ratio of the discharge energy E to the impulse bit I) can be found and, remarkably, is independent of the state of capacitor and power conditioning technologies. This independence allows unfolding the relations between the module mass, E/I, and the mission requirements in a single plot that is applicable for a wide range of delta-v and payload masses. The use of the model to characterize the optimal design of a pulsed plasma thruster system is illustrated with the example of a 10-year north-south stationkeeping of a medium size commercial satellite at geosynchronous orbit. We show that even with off-the-shelf capacitors, the use of such thrusters can result in propulsion mass fractions as low as 6.4%.