Abstract: A plurality of indexing brackets having indexing apertures are secured to a retractable boom in spaced relation. A like plurality of indexing bulkheads are hinged to a foldable panel array (or collapsible spiral antenna) at spaced hinge axes. The bulkheads have indexing prongs which engage the indexing apertures, the brackets pullings the bulkheads therewith as the indexing apertures and prongs engage. Force contact spring motors urge the brackets and bulkheads together in the engaged state. Alignment guides align the brackets and bulkheads during engagement and disengagement of the indexing apertures and prongs.