Optical experiments and model validation of perturbed starshade designs at the Princeton starshade testbed

Starshades are a leading technology to enable the direct detection and spectroscopic characterization of Earth-like exoplanets. Critical starshade technologies are currently being advanced through the S5 Project and at the Princeton starshade testbed. We report on the conclusion of Milestone 2 of the S5 Project, optical model validation. We present results from optical experiments of starshades with intentional perturbations built into their design. These perturbations are representative of the type of perturbations possible in a flight design and serve as points of validation for diffraction models and error budgets. We show agreement between experiment and diffraction model that meets the Milestone 2 criteria of 25% agreement. We then place these results into the larger context of the design and error budget of a full scale starshade mission. We also present the latest updates to the development of non-scalar diffraction models relevant to the testing of sub-scale starshades. This work completes the optics-focused S5 technology milestones that put starshade technology at TRL 5.