1. White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters
- Author
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Levinton, Douglas B, Cash, Webster C, Gleason, Brian, Kaiser, Michael J, Levine, Sara A, Lo, Amy S, Schindhelm, Eric, and Shipley, Ann F
- Subjects
Lunar And Planetary Science And Exploration - Abstract
A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades.
- Published
- 2007