Flightweight magnets for space application using carbon nanotubes

In this paper the premise that carbon nanotubes can be used for lightweight airborne magnets with greatly reduced size and weight is explored. The attraction comes from reports in the literature that carbon nanotubes have current densities several orders of magnitude larger than conventional superconductors and that their strength-to-weight ratio is a fifty times that of steel. Measurements of tensile strength pretty well verify the latter claim, although development of the technology to produce the composite material and manufacturing of the carbon nanotubes in the required lengths remain to be accomplished. Their application as high current carrying conductors with low resistance in long lengths and/or bundles is less certain. Although some researchers have reported superconductivity in the carbon nanotubes, in carbon "bucky balls" and in carbon nanotubes filled with bucky balls, there is not sufficient data on current densities as a function of temperature and magnetic field to definitively characterize the desired magnet applications. In this paper, we postulate some characteristics and examine the resulting potential. If the conductors perform anything like the predictions (which are based on the measured properties of MWCNTs of only micron lengths), they will have a dramatic impact on the feasibility of airborne and space borne systems requiring magnets. The main thrusts of the NASA follow-on program are to get that basic superconductivity data and to learn how to manufacture coils using carbon nanotubes.