Externally, the sphere is made up of rectangular panels metallic/ceramic composites. About two thirds of these measure 601 by 826 metres, and the remaining third measure 601 by 413 metres. The significance of the dimensions and the proprtion of large to small panels is as yet unknown.
While the shell of the Dyson Sphere is composed of carbon-neutronium, the exterior panels are of more conventional materials. The basic structure of the panels is composed of a foamed tritanium/dikieferate alloy. This is covered by several thin layers of tritanium and duranium.
The purpose of many of the structures on the exterior surface is still unknown, although some are obviously a reaction-control system to keep the Sphere centred on the central star. Others, originally mistaken for communications arrays, appear to be computer interfaces. It is these which, when subjected to a standard Federation hailing frequency or sensor scan, activate the automatic process which opens the portals and tractor beams. One of these has been removed by Starfleet personnel and is being studied at the technological assessment laboratories at Starbase 21.