Microwave Propulsion - Progress in the EmDrive Programme
- Paper number
IAC-08.C4.4.7
- Author
Mr. Roger Shawyer, Satellite Propulsion Research Ltd, United Kingdom
- Year
2008
- Abstract
This paper provides an update on the programme of research and development into a new form of electric propulsion. EmDrive technology provides direct conversion of electrical energy to thrust, using radiation pressure at microwave frequencies in a tapered, high Q, resonant cavity. The work has been carried out with both UK government funding and private investment. A summary of the theory behind EmDrive is given, followed by answers to the most frequently asked questions concerning the production of net force, conservation of momentum and conservation of energy. The theory clearly derives equations for both static and dynamic thrust from the basic laws of physics. The experimental work completed to date is described. A feasibility study, leading to proof of concept, was carried out over two years. This work included extensive testing of an S Band experimental thruster which gave a measured static specific thrust of 19 mN/kW for a Q of 5,000. The test programme was specifically designed to eliminate all spurious forces from the results. Development of a Demonstrator Engine was carried out over a further 3 years. This engine gave a static specific thrust of 214 mN/kW at a Q of 35,000. The engine was once again subject to extensive thrust balance tests and fully documented. Independent reviews were carried out on the technical reports from both programmes. The Demonstrator Engine was then dynamically tested on an air bearing rig to simulate a 100 kg spacecraft being accelerated under weightless conditions. The resulting thrust was calculated from the measured acceleration, and gave a specific thrust of 287 mN/kW. The paper also gives a progress report on current programmes. These include an experimental superconducting thruster. This low power, HTS device operates at liquid nitrogen temperature, and is designed for very high Q and consequently high specific thrust. A second programme covers the design and development of a 300 Watt C Band flight thruster, with a specified thrust of 85 mN. A Demonstrator Satellite proposal is also described, based on an existing 100 kg microsatellite design, propelled by a 67 W thruster. The mission objectives include LEO satellite inspection, LEO to GEO transfer, and a terminal velocity of 16.5 km/sec after 7 years of continuous operation. This modest satellite proposal illustrates the potential impact of this new technology on future mission planning.
- Abstract document
- Manuscript document
IAC-08.C4.4.7.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.