PPE Electric Propulsion Advancing to CDR: 12kW String

String level testing is a vital part of electric propulsion development. With the Power and
Propulsion Element (PPE) spacecraft flying two new models of Hall Thrusters, this work is
even more critical. PPE will have both 6kW and 12kW thruster strings onboard, all powered
by Maxar power processing units (PPU). Both strings have recently undergone end-to-end
string level hot fire testing to verify the ability of all components to work together. This entails
operating the thruster with the Xenon Flow Controller (XFC) and PPUs under both nominal
and off-nominal conditions to stress the system and determine weak points. Such testing has
long been a standard Maxar practice since our first 1.5kW electric propulsion system in 2004.
This paper will focus on Phase 1 of the 12kW testing recently completed at NASA Glenn. The
primary conclusion of the test effort was that the 12kW string operated nominally and that
the PPU and XFC could operate the thruster within specifications.