Technology development for the starshade to enable high contrast imaging

Abstract

The Starshade is an external occulter being developed for a future exoplanet imaging and characterization mission. The large, petal-shaped screen efficiently blocks starlight (to better than 1 part in 1010) by using precisely-controlled edges to suppress diffraction and prevent the formation of Arago's spot. A conventional telescope, operating in the shadow of the starshade, then has an unobstructed view of any companion terrestrial planets; these observations require a 4m or larger telescope in order to provide adequate sensitivity and resolution. The starshade itself must be tens of meters across and the starshade structure must therefore be deployable to fit within existing launch vehicles. As a point of departure, we present the New Worlds Observer mission concept, which uses a 62m tip-to-tip starshade with a 4m telescope, separated by 80,000 km. Our fundamental starshade design philosophy includes using high-heritage, high-TRL components and passive control of the starshade's precision structure. This paper outlines the driving requirements for the starshade payload and our design elements that meet these requirements. We have developed a roadmap and a technology maturation plan for the starshade payload. We discuss pathfinder units we have build for this and other components of the starshade, and the current state of the art towards meeting starshade tolerance requirements. We present thermal and dynamics analyses of our starshade design and show that the design is within the error budget. We will motivate the path forward leading to a subscale demonstration of the starshade and show that this is a useful part of an overall starshade technology development program.