DESIGN AND ANALYSIS OF TENSIONING AND INFLATION SYSTEM FOR GOSSAMER SPACE STRUCTURE

Abstract

The present space innovation is empowering the activities of satellite configuration in higher orbits to enhance gain capabilities. The large size of the space structures is the most generalised solution for the increasing the gain of the satellite reflector antennas. Inflatable membrane structures are greatly attracting the interests of scientists as a scientific platform in outer space exploration missions due to their outstanding performance in weight and stowage volume. The inflatable membrane structures are extremely lightweight and high structural efficiency. The membrane structures are possesses negligible bending stiffness therefore the maintaining its surface profile is the challenging task for the space industries in the world. Therefore, the anchor point configuration and the tension forces are important design parameter in the design of the space borne membrane structures. The next level of research will require connecting and inflation system for the spaceborne membrane reflector considering the space environmental conditions. Hence, this research work presents the numerical and experimental analyses of tensioning, connecting and inflation technique for inflatable planar and parabolic reflector. First part of the present work discusses the tensioning analysis of the planar and paraboloid membrane structures. The novel methodology for finding the tension force with different anchor point configuration of the membrane reflector is presented. The minimum number of anchor points needed are found from the tension force and anchor point relation. The novel trend-line equation for the tension force and the scaling factor is established. The tension force can be directly calculated using the same trend-line equation with a scale factor of Radio-Frequency (RF) area for any size of reflector. The Taguchi orthogonal array was deployed for the reducing the margin geometry optimization for objective function as minimization of the mass penalty to the satellite system. The tension forces are required to maintain the state of stresses are found out. The three types of the tensioning methods such as Kevlar chord, constant force spring, and wave sprigs are studied for their advantages and limitations. The tensioning device are developed for the single layer and multi-layered planar membrane reflector antenna. The second part of this study covers the design of the connecting mechanism for the planar membrane reflector antenna. The developed flexural-based canister mechanism acts as a housing part of an inflatable membrane reflector, which is used to deploy the membrane reflector into a predefined position once the satellite reaches orbit. The proposed flexural-based canister also acts as a connecting part between the satellite and reflector. The developed mechanism uses flexural linkages so that significantly less actuation power source is required to perform the required motion. The last part of the analysis is focused on inflation system for the inflatable spaceborne membrane structure. The study is carried out using for the residue gas inflation method for the complete deployment of the spaceborne inflatable boom through analytical, numerical and experimental approaches. The effect of different mass of the residue gases along with three folding patterns on the deployment behaviour is investigated. The novel relation was developed for the calculation of the safe mass of residue gases which can be carried for the full deployment of the inflatable boom. The developed analytical relation can use to find out the safe of residue gases for any size of boom. The results show that the total inflation time is inversely proportional to the mass of the residue gases. Through the comparative study, it has been observed that the change in the inflation time is negligible for different folding patterns with the same mass of residue gas. The result shows that a sufficient amount of residue gas is successfully deploying the inflatable boom in the vacuum environmental condition keeping the stresses in the boom in the tolerance limit. The residue gas inflation method is a simple and cost-effective solution for the inflation of spaceborne membrane structures.