A report proposes that solar sails for spacecraft be constructed in segments in such a way as to minimize stresses. The segments could be made of metallized fabric or film and could be connected by short, strong tethers. Alternatively, the segments could be like islands, held loosely in pockets bounded by fibers. For stowage during transport to outer space, the sails could be folded along the gaps between segments, so as to minimize folding stresses in the sail material. Because tensile and other stresses in the sail material would be minimal, the sail material could be made in a thickness of the order of a micron and could thus be very lightweight. In cases in which there are requirements for sails to sustain tensile stresses, carbon-fiber nets like those described in the preceding article could be used.
This work was done by Charles Garner of Caltech for NASA's Jet Propulsion Laboratory. To obtain a copy of the report, "Segmented Solar Sail Design," access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Materials category.