Atmospheric Modeling
====================

This example demonstrates the simplified thermosphere model and drag calculations for analyzing satellite orbital decay and atmospheric interactions.

.. raw:: html

   <div class="plotly-container">
       <iframe class="plotly-iframe" src="../../_static/images/examples/geophysical_gravity_altitude.html"></iframe>
   </div>

Overview
--------

Atmospheric density models are essential for:

- **LEO satellite operations**: Predicting orbital decay and drag
- **Reentry analysis**: Determining vehicle heating and trajectory
- **Space weather effects**: Understanding solar activity impacts
- **Mission planning**: Fuel requirements for station-keeping

Key Scenarios
-------------

**ISS Altitude Profile**
   Atmospheric density varies significantly with solar activity level,
   affecting ISS orbital decay rate and reboost requirements.

**Satellite Drag**
   Drag coefficients depend on satellite geometry and atmospheric
   composition at orbital altitudes.

**Temperature Profiles**
   The thermosphere temperature increases dramatically with altitude
   and varies with solar flux (F10.7) and geomagnetic activity (Ap).

**Composition Transitions**
   The atmosphere transitions from molecular (N2, O2) to atomic (O, He, H)
   species with increasing altitude.

.. raw:: html

   <div class="plotly-container aspect-square">
       <iframe class="plotly-iframe" src="../../_static/images/examples/orbital_propagation.html"></iframe>
   </div>

**Orbital Decay**: Atmospheric drag causes LEO satellites to gradually lose altitude, with decay rate depending on solar activity levels.

Models Covered
--------------

**Simplified Thermosphere**
   - Barometric per-species model with solar-activity (F10.7) and
     geomagnetic (Ap) inputs
   - Usable above ~200 km (within ~2x of published NRLMSISE-00 values);
     below ~86 km use the US Standard Atmosphere instead (gh-79)

**US Standard Atmosphere 1976**
   - Reference atmosphere up to 85 km
   - Useful for comparison and validation

Code Highlights
---------------

The example demonstrates:

- Density profiles across altitude with ``SimplifiedThermosphere()``
- Species composition (N2, O2, O, He, H, Ar, N) vs altitude
- Temperature profiles under various solar activity levels
- Solar flux (F10.7) effects on ISS-altitude conditions
- Comparison with US Standard Atmosphere 1976

Source Code
-----------

.. literalinclude:: ../../../examples/atmospheric_modeling.py
   :language: python
   :linenos:

Running the Example
-------------------

.. code-block:: bash

   python examples/atmospheric_modeling.py

See Also
--------

- :doc:`../orbital/orbital_mechanics` - Orbital propagation
- :doc:`../orbital/relativity_demo` - Relativistic corrections
- :doc:`../orbital/ephemeris_demo` - Planetary positions