thrust performance comparison of a ppt using solid propellant and powdered propellant
- Paper number
IAC-08.C4.4.10
- Author
Mr. Takefumi Saito, The University of TOKYO, Graduate school, Japan
- Coauthor
Dr. Hiroyuki Koizumi, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Dr. Hitoshi Kuninaka, Japan Aerospace Exploration Agency (JAXA), Japan
- Year
2008
- Abstract
A pulsed plasma thruster with solid propellant PTFE is now expected as one of the most adequate thrusters to be used on microspacecraft, which are called “microthrusters” because of their simple structure. However, there are some motivations for researching on propellant type of PPTs furthermore. An APPT has a restriction of configuration of solid propellant. We suggest an entirely new idea of using powdered propellant instead of such solid propellant for a PPT. Powdered propellant has a fluidical nature, that is, it can be supplied freely. So the problem of restriction of propellant configuration can be solved. Additionally, typical PPTs with solid propellants have a problem of nonuniform ablation. Generally, ablation of solid propellant does not occur uniformly. Therefore, after long-life-time operation, the surface of propellant changes its shape and the performance of the thruster should changes gradually. Using powdered propellant, and controlling its supply, we can renew the propellant surface exposed to plasma in optional timing. So a powdered propellant PPT could have an advantage over traditional solid propellant PPTs in long time operation. In order to compare the thrust performance of a powdered propellant PPT with that of a solid propellant PPT, we have made a test model thruster with parallel plate electrodes. Solid PTFE or powdered PTFE is used as propellant. Experimenting as a solid propellant PPT, we put a rectangular solid PTFE between the electrodes. Experimenting as a powdered propellant PPT, we put a rectangular solid ceramic between the electrodes in the same configuration as the above solid PTFE, and spread PTFE powder (0.25 ?m diameter) on the ceramics with a uniform thickness of about 1 mm. To measure impulse bit and propellant consumption, we made a “Thrust Mass Balance”, with which we can measure them simultaneously in vacuum. This is a torsion balance type of thrust stand with horizontal rotation axis. As a result, the specific impulse of the powdered propellant PPT was 240s, which is much smaller value than 1100s; that of the solid propellant PPT. To improve thrust performance, we used a porous ceramic and spread PTFE powder as thinly as possible. The specific impulse of this type of powdered propellant PPT was 1040s. In this way, we have succeeded in improvement of thrust performance of the powdered propellant PPT to a similar extent to the solid propellant PPT. Considering above merits of powdered propellant, we proved availability of powdered propellant PPTs.
- Abstract document
- Manuscript document
(absent)