Large Deployable Space Antennas Based on Usage of Polygonal Pantograph

This paper describes large space antenna projects based on application of a closed polygonal pantograph truss used for transforming, deploying, and prestressing the reflector structure. Their reflecting surfaces represent a flexible mesh fabric. Two means of maintaining the surface are discussed herein. The first technique is associated with employment of forces of the gravity field gradient. The second is based on the use of a flexible carcass prestressed by internal forces applied to the pantograph. Reflectors of the second kind have a rather complicated mechanical structure depending on the way of their attachment to a carrier. Provisions are made for supporting the reflector by an articulated arm linked with its central interface and through the use of tube beams, supporting the reflector periphery structures. During the design of the reflectors, special attention was paid to the problems of their structural simulations at the stages of their launching, deployment, and orbital motion. The deployable antennas considered can be enabling elements for many space missions ranging from communications to other satellite systems, including radar, remote sensing, interferometry, wireless power transmission, etc. They exhibit an enhanced stiffness of structure, required for the digit tele- and radio-communication and navigation, which makes it possible to diminish ray scattering, to raise the power of the accepted signals, and to prevent frequency losses.