ABSTRACT TO ENABLE DEEP SPACE EXPLORATION MISSIONS SPACECRAFT STRUCTURES WITH LARGE SURFACE AREA SUCH AS SOLAR SAILS SOLAR ARRAYS AND ANTENNAS ARE NECESSARY FOR DELIVERING PROPULSION POWER AND COMMUNICATION CAPABILITIES. THIN-PLY COMPOSITES ARE A PROMISING BUILDING BLOCK TECHNOLOGY FOR CONSTRUCTING DEPLOYABLE STRUCTURES DUE TO THEIR EFFICIENT MASS AND PACKAGING EFFICIENCY. A CHALLENGE FACING THIN-PLY COMPOSITES IS DEPLOYMENT RELIABILITY. DURING OPERATIONS DEPLOYABLE COMPOSITE STRUCTURES ARE FOLDED KEPT STOWED FOR AN EXTENDED PERIOD OF TIME WITH VARYING TEMPERATURES AND DEPLOY IN ORBIT. BECAUSE OF VISCOELASTICITY OF THE MATRIX THE DEPLOYMENT COULD POSSIBLY COME TO A STALL. ALSO THE DEPLOYED SHAPE IS NOT ACHIEVED IMMEDIATELY BUT IS GRADUALLY RECOVERED OVER TIME. BOTH THE DEPLOYMENT AND SHAPE RECOVERY IS HEAVILY INFLUENCED BY THE STOWAGE TIME AND TEMPERATURE. IT IS CRITICAL TO DEVELOP A SYSTEMATIC MEANS TO EVALUATE VISCOELASTIC RESPONSE OF COMPOSITE STRUCTURES TO ENSURE DEPLOYMENT RELIABILITY AND SHAPE ACCURACY IN SPACE. THE OBJECTIVE OF THIS PROJECT IS TO STUDY THE EFFECT OF VISCOELASTICITY ON THE DEPLOYMENT BEHAVIOR THROUGH COMPUTATIONAL MODELING AND EXPERIMENTAL CHARACTERIZATION. THE VISCOELASTIC RESPONSE OF THIN-PLY COMPOSITES IS HIGHLY DEPENDENT UPON THE ORIENTATION AND GEOMETRY OF THE TOWS AND THE MECHANICAL PROPERTIES OF THE MATRIX AND FIBER. WE PROPOSE FOUR TASKS TO MODEL AND CHARACTERIZE COMPOSITE MATERIALS BASED ON THEIR LAMINATE CONFIGURATIONS AND MATERIAL PROPERTIES AND APPLY THESE MODELS TO PREDICT RESPONSE OF THIN-PLY COMPOSITE TAPE-SPRINGS AND BOOMS DURING STOWAGE AND DEPLOYMENT.