An Experimental Study on Carbon Nanotube Cathodes for Electrodynamic Tether Propulsion
- Paper number
IAC-05-C4.4.07
- Author
Dr. Yasushi Okawa, Japan Aerospace Exploration Agency (ISTA/JAXA), Japan
- Coauthor
Dr. Shoji Kitamura, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Ms. Satomi Kawamoto, Japan Aerospace Exploration Agency (ISTA/JAXA), Japan
- Coauthor
Mr. Yasushi Iseki, Japan
- Coauthor
Dr. Kiyoshi Hashimoto, Japan
- Coauthor
Dr. Etsuo Noda, Japan
- Year
2005
- Abstract
This paper describes an experimental investigation on field emission cathodes (FECs) for electrodynamic tether (EDT) propulsion. In the Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency (JAXA), we are making an effort to develop an EDT propulsion system for space debris removal. In this EDT system, FECs will play very important role because the EDT can be a totally propellant-free propulsion system by using the FEC as an electron-emitter and a bare wire as an electron-collector. In various types of FECs, we selected carbon nanotube (CNT) type emitters for the EDT application because CNT-FECs have high tolerance to high-voltage breakdown and are operable under relatively low vacuum condition. In our preliminary experiments, two types of multi-wall CNTs were tested; CNTs made by thermal chemical vapor deposition (CVD) and ones by arc discharge process. The electron extraction tests were performed in diode mode (without a gate electrode). Results showed that 1) an electron emission current over 120 mA was obtained from 40 mm diameter CVD-CNTs but current stability was not satisfactory and 2) a stable electron current of 2 mA was extracted from 4 mm diameter arc-CNTs. In both the cases, electron emission current densities over 10 mA/cm2 were achieved and this magnitude was large enough for future EDT application. As a next step, we are pursuing the electron extraction tests in triode mode, which is essential for space application. In the triode mode operation, suppressing the electron flow to a gate electrode is important to avoid thermal deformation of the electrode. Numerical calculations were performed to simulate electron trajectories and to determine the appropriate electrode configuration. Results of the electron extraction tests are to be presented in the conference.
- Abstract document
- Manuscript document
IAC-05-C4.4.07.pdf (🔒 authorized access only).
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