MicroPPT Development for Small Spacecraft Propulsion
Abstract
A class of miniaturized pulsed plasma thrusters (PPT), known as MicroPPTs, is currently in development at the Air Force Research Laboratory. Operating by means of a surface discharge across a Teflon (TM) propellant fuel bar only a few millimeters in diameter, the MicroPPT delivers a thrust-to-power ratio of 5-10 Micro-N-s/J. In the near term, these thrusters can provide propulsive attitude control on 150-kilogram-class spacecraft using one-fifth the dry mass of conventional torque rods and reaction wheels. Eventually these thrusters are designed for primary and attitude control propulsion on future 25-kilogram-class spacecraft. Efforts to characterize MicroPPT performance and the thruster plume are underway. To this end, a modified torsional thrust stand has been developed for the purpose of accurately measuring the low-level thrust generated by the MicroPPT. A Herriott Cell interferometer is introduced to establish the plume electron and neutral densities. Comparison of the measured electron density with modeling predictions shows close agreement. Additionally, a Pockels cell has been developed to provide a zero-impedance MicroPPT breakdown voltage measurement, and an intensified CCD array has been used to characterize the divergence of both the thruster plume and the late-time particulate emission. A synopsis is presented of the status of the thruster's development, including lifetime, thermal, and environmental testing. (2 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 14, 2002
- Accession Number
- ADA410467
Entities
People
- Daron R. Bromaghim
- David White
- Gregory G. Spanjers
- John H. Schilling
- Stewart S. Bushman
Organizations
- Air Force Research Laboratory