Luna Innovations proposes to develop a distributed fiber-optic shape sensor to provide a control system for the deployment of ultra-lightweight inflatable support structures for solar sails. This shape sensing system will provide the full-field 3D shape of the lightweight inflatable booms of solar sails at all points to sub-millimeter accuracy, permitting the monitoring of the dynamics of the structure before, during, and after deployment. These shape sensors, when fully integrated with the booms of solar sails and other inflatable space structures, will permit real-time active control of the deployment by providing a closed-loop feedback mechanism. Because the sensors and the system to monitor them will cost and weigh substantially less than the stereoscopic cameras currently used to monitor the 3D shape, this approach is highly desirable. By providing a reliable, lightweight means to monitor the dynamic solar sail deployment process, the risks associated with employing sail technology as a means of spacecraft propulsion will be substantially mitigated. This development will broadly enhance NASA's 'Missions in the Exploration of the Solar System' theme.