High Performance Iodine Feed System

Busek is developing an advanced iodine feed system for Hall Effect Thrusters (HETs), ion engines, cathodes, and other plasma generators. The feed system features an innovative piezo driven valve that saves volume, mass, cost, and energy with respect to state of the art alternatives. The feed system also features a low mass plastic propellant tank that may be manufactured through additive processes. This allows low cost, complex shapes that can maximize the use of available space inside volume-restricted spacecraft. The feed system will be especially attractive for small spacecraft and CubeSats. Iodine stores as a solid and sublimates at modest temperatures as the molecule I2, which allows many benefits with respect to traditional Hall effect thruster fuels such as xenon and krypton. These advantages include higher storage density, lower storage pressure, the ability to test high power systems at space-relevant conditions in modest facilities, the capability to store propellant in space without active regulation, and the capacity to transfer propellant at low-pressure conditions in space. In a space-limited spacecraft, using iodine instead of state of the art xenon could increase available delta-V by a factor of three (3) or more. In Phase I, Busek developed a feed system featuring the advanced components, which was integrated into the iSAT spacecraft form factor. The system was then tested with an iodine compatible Hall effect thruster in relevant space conditions. In Phase II, an improved feed system will be designed, built and tested. Major Phase II technical objectives include developing an engineering model iodine resistant, piezo driven flow control valve, finalizing the feed system control architecture, identifying and evaluate commercial components to fill out the system, and building and characterizing the system. At the conclusion of the Phase II effort, engineering model valves will be delivered to NASA for further characterization.