Abstract
A starshade is a concept for a deployable external occulter to a telescope that enables the imaging of exoplanets by blocking out the light of the host star. The starshade architecture has an inner disk structure consisting of a lightweight opacity blanket and a stiff perimeter truss. The opacity blanket is called the optical shield and folds with an origami-inspired spiral wrapping pattern. The inner disk architecture has a physical gap: there is a difference in geometry between the perimeter truss and optical shield in both the stowed and deployed configurations. To demonstrate the deployment of the starshade inner disk at a higher level of fidelity, an opaque closeout must be developed to span the difference in geometric shape. Here we describe the design of an origami-motivated closeout design for the optical shield. We propose several closeout fold patterns, for which we optimized the difference in normalized fold line lengths between the folded and unfolded states to be less than 0.01%. The close-out patterns are then validated by simulation and prototyping. These patterns may be realized with flight-like materials and will enable the technological maturation of the starshade concept.
