To support NASA's vital interest in developing much larger solar array structures over the next 20 years, MotionPort LLC's Phase I SBIR project will strengthen validated modeling analysis and simulation techniques by developing a vertical application to simulate the nonlinear dynamics of the various stages of deployable space structures. This application which will support RecurDyn Multi-Body Dynamics (MBD) software, acquired by NASA in 2013, will increase efficiency and reduce errors, time and the need for advanced knowledge. Currently, modeling complex flexible body non-linear structures can be time consuming and prone to error. Existing nonlinear structural analysis simulation software does not effectively simulate structural assemblies with significant motion. Creation of a custom vertical application for the simulation of deployable space structures would provide a large reduction in the specialized knowledge needed to develop models and would automate tedious tasks. The proposed innovations of this Phase I SBIR project are: 1. A focused vertical software application for the dynamic simulation of the rollup, deployment and maneuvering operation of large solar array structures consisting of a set of functions that are layered on commercial Multi-Body Dynamics (MBD) simulation software that also has the capability of the nonlinear simulation of flexible (Finite-Element [FE] or mesh-based) bodies; and 2. Development of an active, nonlinear controller that will reduce the deflection of a roll-out solar array (ROSA) during spacecraft maneuvers. This development includes the creation and use of a unique simulation environment that couples the controller simulation with the nonlinear structural response of the ROSA. The Phase II project will add capabilities and improve integration of functions, including new support of the simulation of lanyards and tape springs. Additional type of deployable space structures can be simulated, including antennas.