Eidolon Interstellar Medium Survey

A lightsail moving at a few per cent of light speed meets every dust grain like a bullet. To size the shielding for the Eidolon Lightsail Prototype, Kwame Asante's team gathered every available measurement of the interstellar medium along the 4.2 light-year line toward Proxima Centauri, and added new readings from instruments carried beyond Neptune.

The survey includes dust density estimates, the heliospheric hydrogen wall, and results from erosion tests where sail samples were bombarded in laboratory accelerators. It underpins the 265,000 AU design range quoted for Eidolon.

All of it is open under CC-BY-4.0. Interstellar research groups worldwide have adopted the dataset as a common baseline, and several have published alternative shielding designs using it.

The team invites additional laboratory erosion results and independent dust models. To get started, pick up dust density along the Proxima route, hydrogen wall measurements and sail erosion test results, all published under CC-BY-4.0, with source and documentation at https://git.halcyon.example/eidolon-ism. New contributors are paired with a maintainer for their first change, and the project holds a monthly open call where partners, students and Halcyon engineers compare notes. Releases are versioned and archived, so analyses can always be reproduced against the exact data or code they used.