Data source: NOAA Space Weather Prediction Center — solar wind at the L1 Lagrange point (5-minute cadence); planetary Kp index. Sliders lock to live values on fetch; adjust speed, density, Bz and Kp manually to model alternate scenarios.
Listen: a sonification, not a power source. Speed sets pitch (200–900 km/s → 110–440 Hz). Bz sets the interval above it: northward is a consonant fifth, southward a beating semitone. Density sets the crackle rate. Kp sets the roughness (tremolo).
Band VII instrument — Terran Series, Document XXI, Contribution 34. Sail thrust follows dynamic pressure (n·m_p·v²), so speed and density feed one propulsion score rather than being rated separately; the working threshold for Optimal is 3 nPa. Bz and Kp are Earth-side operational checks. The rating is weakest-link: the lowest of the three scores is the rating, so a strong wind with a strongly southward Bz or a storm-level Kp is not a window. Score bands beyond the 3 nPa, Kp < 3 and Bz near-zero-or-positive optima are provisional working thresholds. The rating supports navigator judgment; it does not replace it.