Interactive thermosphere + exosphere (80–2000 km). Jacchia-style
surrogate mirroring the Parker Physics DSMC pipeline; switches to
SPARTA-refined tables once the offline grid ships. Inputs are live
indices — F10.7 cm flux and Ap.
shells at 150 · 250 · 400 · 600 · 900 · 1500 km
opacity ∝ log ρ · cyan ring = current altitude