Spherical collectors versus bare tethers for drag, thrust, and power generation

Sanmartín Losada, Juan Ramón and Lorenzini, Enrico C. (2006). Spherical collectors versus bare tethers for drag, thrust, and power generation. "IEEE Transactions on plasma science", v. 34 (n. 5); pp. 2133-2139. ISSN 0093-3813.

Description

Title: Spherical collectors versus bare tethers for drag, thrust, and power generation
Author/s:
  • Sanmartín Losada, Juan Ramón
  • Lorenzini, Enrico C.
Item Type: Article
Título de Revista/Publicación: IEEE Transactions on plasma science
Date: 2006
ISSN: 0093-3813
Volume: 34
Subjects:
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Física Aplicada a la Ingeniería Aeronáutica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Deorbit, power generation, and thrusting performances of a bare thin-tape tether and an insulated tether with a spherical electron collector are compared for typical conditions in low-Earth orbit and common values of length L = 4−20 km and cross-sectional area of the tether A = 1−5 mm2. The relative performance of moderately large spheres, as compared with bare tapes, improves but still lags as one moves from deorbiting to power generation and to thrusting: Maximum drag in deorbiting requires maximum current and, thus, fully reflects on anodic collection capability, whereas extracting power at a load or using a supply to push current against the motional field requires reduced currents. The relative performance also improves as one moves to smaller A, which makes the sphere approach the limiting short-circuit current, and at greater L, with the higher bias only affecting moderately the already large bare-tape current. For a 4-m-diameter sphere, relative performances range from 0.09 sphere-to-bare tether drag ratio for L = 4 km and A = 5 mm2 to 0.82 thrust–efficiency ratio for L = 20 km and A = 1 mm2. Extremely large spheres collecting the short-circuit current at zero bias at daytime (diameters being about 14 m for A = 1 mm2 and 31 m for A = 5 mm2) barely outperform the bare tape for L = 4 km and are still outperformed by the bare tape for L = 20 km in both deorbiting and power generation; these large spheres perform like the bare tape in thrusting. In no case was sphere or sphere-related hardware taken into account in evaluating system mass, which would have reduced the sphere performances even further.

More information

Item ID: 21740
DC Identifier: http://oa.upm.es/21740/
OAI Identifier: oai:oa.upm.es:21740
Deposited by: Biblioteca ETSI Aeronauticos
Deposited on: 22 Nov 2013 10:56
Last Modified: 21 Apr 2016 12:28
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