Two concepts for space propulsion based on thermal nuclear fusion
- Paper number
IAC-12,C4,7-C3.5,6,x13791
- Author
Mr. Roland Antonius Gabrielli, Institute of Space Systems, Universität Stuttgart, Germany
- Coauthor
Prof.Dr. Georg Herdrich, Institute of Space Systems, Germany
- Coauthor
Dr. Dejan Petkow, Advanced Concepts Team, ESA, The Netherlands
- Coauthor
Prof. Hans-Peter Röser, University of Stuttgart, Germany
- Year
2012
- Abstract
In the present work, two different concepts for fusion based space propulsion are compared. While the first concept is based solely on propulsion by hypothetic ejection of fusion products and hence may be called “ash drive”, the second one uses an additional coolant for thrust enhancement. Since this coolant was initially assumed to be gaseous and to do most of the propulsion work, the name of “working gas drive” has been proposed. The comparison is based on the evaluation of analytic models describing the system from the fusion plasma to propulsion subsystems. The plasma models use a generalised Lawson criterion [1] including both reactants and products. Characteristic timescales, temperature and mixture ratios are considered as parameters. The plasma models yield volume specific parameters as a function of the temperature. Further models scale system masses assuming generic spherical geometries and manage the system power flow. The propellant mass flow rate is estimated considering ash production [1] for ash drives and cooling requirements for working gas drives [2]. The model for specific exhaust velocities respects relativistic effects in view of prospectively high thrust power. The thrust is calculated classically from exhaust velocity and mass flow rate. The models for both types of fusion drives are evaluated for four major fusion reactant couples (D–T; D–3He; 3He–3He; 11B–p) [3]. In working gas drives, hydrogen is considered as coolant due to its caloric and propulsive properties. The results of the comparison show that while ash drives excel working gas drives in terms of specific exhaust velocities the latter yield considerably more thrust than ash drives. Another major drawback of the ash drives are relatively small thrust efficiencies. The plasma power has to be disposed of nearly entirely as waste heat leading to prohibitive radiator masses. \bigskip {\bf References:} [1] D. Petkow, R.A. Gabrielli, G. Herdrich, R. Laufer, H.-P. Röser: “Generalized Lawson criterion for magnetic fusion applications in space”, Fusion Engineering and Design, Volume 87, Issue 1, Pages 30-38, January 2012. [2] D. Petkow, R.A. Gabrielli, G. Herdrich, R. Laufer, and O. Zeile: “A Generic Model for a Transpiration Cooled Fusion Propulsion System”, 27th International Symposium on Space Technology and Science, Tsukuba, Japan, 2009 [3] D. Petkow, G. Herdrich, R. Laufer, R.A. Gabrielli, O. Zeile, H.-P. Röser: “Comparative investigation of fusion reactions for space propulsion applications”, Transactions of Japan Society for Aeronautical and Space Sciences, Space Technology, Japan, Vol.7 (2009) Pb 59 – Pb 63.- Abstract document
- Manuscript document
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