tobari

Earth environment models for orbital mechanics.

Atmosphere

Provides pluggable atmospheric density models behind the AtmosphereModel trait.

• Exponential — US Standard Atmosphere 1976, altitude-only (simplest, no epoch needed)
• HarrisPriester — diurnal density variation using Sun position
• Nrlmsise00 — full empirical model driven by solar and geomagnetic activity indices

All models implement AtmosphereModel and can be swapped at runtime via Box<dyn AtmosphereModel>.

Magnetic field

Provides pluggable geomagnetic field models behind the magnetic::MagneticFieldModel trait.

• magnetic::TiltedDipole — simple tilted dipole approximation (fastest)

Space weather

The space_weather module defines SpaceWeather conditions and the SpaceWeatherProvider trait for supplying time-varying solar/geomagnetic data. CssiSpaceWeather parses CelesTrak CSSI-format files and (with the fetch feature) downloads them automatically with local caching.

Data attribution

Space weather indices are sourced from:

• Kp/Ap geomagnetic indices: GFZ Helmholtz Centre for Geosciences (CC BY 4.0)
• F10.7 solar radio flux: NOAA SWPC / NRCan DRAO (public domain)
• Aggregated and distributed by CelesTrak (https://celestrak.org/SpaceData/)

Traits

Name	Description
MagneticFieldModel	A geomagnetic field model.
SpaceWeatherProvider	Provider of space weather data for a given epoch.
AtmosphereModel	An atmospheric density model.

Structs

Name	Description
CssiDailyRecord	A single daily record from CSSI space weather data.
CssiData	Parsed CSSI space weather data, sorted by date.
CssiSpaceWeather	Space weather provider backed by CSSI historical data.
Exponential	Piecewise exponential atmosphere model based on US Standard Atmosphere 1976.
HarrisPriester	Harris-Priester atmospheric density model.
TiltedDipole	Tilted dipole geomagnetic field model with ECEF-fixed axis.
GaussCoefficients	Gauss coefficient set for a single epoch.
Igrf	IGRF (International Geomagnetic Reference Field) model.
MagneticFieldInput	Pre-computed input for magnetic field evaluation.
Nrlmsise00Output	Full output of the NRLMSISE-00 model.
Nrlmsise00Input	Input parameters for a single NRLMSISE-00 evaluation.
Nrlmsise00	NRLMSISE-00 empirical atmosphere model.
SpaceWeather	Space weather conditions at a given epoch.
ConstantWeather	Constant space weather — returns the same F10.7 and Ap for all epochs.
AtmosphereInput	Pre-computed input for atmospheric density evaluation.

Enums

Name	Description
CssiParseError	Parse error for CSSI space weather files.
OutOfRangeBehavior	Behavior when the requested epoch is outside the data range.
GfzParseError	Parse error for GFZ space weather files.
SpaceWeatherFormat	Detected space weather data format.

Functions

Name	Description
density	Compute atmospheric density [kg/m³] at the given altitude [km].
parse_gfz	Parse GFZ Kp_ap_Ap_SN_F107_*.txt format into [CssiData].
detect_format	Detect whether text is CSSI or GFZ format.
simple_eci_to_geodetic_latlon	Convert a simple-path ECI position to WGS-84 geodetic latitude and
precise_gcrs_to_geodetic_latlon	Convert a GCRS position + UTC epoch + EOP provider to WGS-84
epoch_to_day_of_year_and_ut	Convert epoch to (day_of_year, ut_seconds).
local_solar_time	Compute local apparent solar time [hours].

Constants

Name	Description
TEMP_COEFFICIENTS	Exospheric temperature variation coefficients (150 terms).
DENSITY_COEFFICIENTS	Density variation coefficients for each species (9 species x 150 terms).
GRADIENT_COEFFICIENTS	Temperature gradient (S-parameter) variation coefficients (150 terms).
CORRECTION_PARAMS	Composition and turbopause correction parameters (2 x 25 terms).
TEMP_BOUNDARY	Temperature boundary and reference values (50 terms).
DENSITY_BOUNDARY	Density boundary parameters per species (8 species x 10 terms).
TEMP_NODE_COEFFICIENTS	Temperature node correction coefficients (4 nodes x 100 terms).
MID_ATMO_COEFFICIENTS	Middle atmosphere variation coefficients (10 x 100 terms).
SAM_COEFFICIENTS	Semiannual multiplier coefficients (100 terms).
MID_ATMO_AVERAGES	Middle atmosphere average values (10 terms).