Introduction
The External Logs panel allows users to export selected simulation variables to an external ASCII file. The generated file is column-based, human-readable, and suitable for direct inspection or post-processing in external tools such as Python, MATLAB, or spreadsheet software.
The panel operates through a simple selection mechanism:
- All variables available for export are listed on the left.
- Variables selected for logging are listed on the right.
- Variables are added or removed using the arrow buttons between both lists.
Only the variables present in the right-hand list are written to the output file. The order of the variables in this list defines the column order in the exported file.
By default, SatModeler includes a minimal but representative set of translational and rotational state variables, which can be extended as needed depending on the analysis objectives.
Variables available for export
The following table lists all variables that can be exported through the External Logs system, along with their definitions and reference frames.
| Variable | Description |
|---|---|
| Position in Earth-Centered Inertial (J2000) | Spacecraft position vector expressed in the Earth-Centered Inertial (ECI) reference frame aligned with the J2000 epoch. Components are [x, y, z] in meters. |
| Velocity in Earth-Centered Inertial (J2000) | Spacecraft velocity vector expressed in the ECI (J2000) frame. Components are [vx, vy, vz] in m/s. |
| Position in Earth-Centered, Earth-Fixed (WGS-86) | Spacecraft position expressed in the rotating Earth-fixed frame associated with the WGS-86 Earth model. Suitable for ground-track and geodetic analysis. |
| Velocity in Earth-Centered, Earth-Fixed (WGS-86) | Spacecraft velocity expressed in the Earth-fixed reference frame, including Earth rotation effects. |
| Keplerian Elements | Extended Keplerian orbital elements derived from the instantaneous inertial state in ECI. The set includes the classical elements (semi-major axis, eccentricity, inclination, right ascension of the ascending node, argument of perigee, true anomaly) plus the additional angular parameters: true argument of periapsis, argument of latitude, and true longitude. All angular quantities are expressed in degrees. |
| Gravity Acceleration in Earth-Centered Inertial (J2000) | Acceleration due to the central gravitational field of the Earth, expressed in the ECI frame (m/s²). |
| Third-Body Acceleration in Earth-Centered Inertial (J2000) | Total acceleration resulting from the sum of all enabled third-body gravitational perturbations, expressed in the ECI frame. |
| Sun Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to the Sun’s third-body gravitational effect, expressed in the ECI frame. |
| Mercury Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Mercury’s third-body gravitational effect, expressed in the ECI frame. |
| Venus Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Venus’ third-body gravitational effect, expressed in the ECI frame. |
| Mars Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Mars’ third-body gravitational effect, expressed in the ECI frame. |
| Jupiter Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Jupiter’s third-body gravitational effect, expressed in the ECI frame. |
| Saturn Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Saturn’s third-body gravitational effect, expressed in the ECI frame. |
| Uranus Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Uranus’ third-body gravitational effect, expressed in the ECI frame. |
| Neptune Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Neptune’s third-body gravitational effect, expressed in the ECI frame. |
| Pluto Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to Pluto’s third-body gravitational effect, expressed in the ECI frame. |
| Moon Acceleration in Earth-Centered Inertial (J2000) | Acceleration contribution due to the Moon’s third-body gravitational effect, expressed in the ECI frame. |
| Solar Pressure Acceleration in Earth-Centered Inertial (J2000) | Acceleration produced by solar radiation pressure, obtained by summing all contributions from each perturbation mesh element, expressed in the ECI frame. |
| Aerodynamic Acceleration in Earth-Centered Inertial (J2000) | Acceleration due to atmospheric aerodynamic forces, obtained by summing all contributions from each perturbation mesh element, expressed in the ECI frame. |
| Angular Velocity in Body Frame | Spacecraft angular velocity vector expressed in the body frame. Components are [ωx, ωy, ωz] in rad/s. |
| Quaternion (Body Frame wrt Earth-Centered Inertial) | Unit quaternion describing the orientation of the spacecraft body frame with respect to the ECI (J2000) frame. |
| Solar Pressure Torque in Body frame | Torque generated by solar radiation pressure acting on the spacecraft geometry, obtained by summing all perturbation mesh contributions, expressed in the body frame (N·m). |
| Aerodynamic Torque in Body frame | Torque generated by aerodynamic forces acting on the spacecraft geometry, obtained by summing all perturbation mesh contributions, expressed in the body frame (N·m). |
| Magnetic Torque in Body frame | Torque generated by the interaction between the spacecraft residual magnetic dipole and the Earth magnetic field, expressed in the body frame (N·m). |
| Gravity Gradient Torque in Body frame | Torque produced by gravity gradient effects due to spacecraft mass distribution and orbital position, expressed in the body frame (N·m). |
| Atmospheric Density | Local atmospheric mass density at the spacecraft position, as provided by the Earth atmospheric model (kg/m³). |
| Magnetic Field in Body Frame | Earth magnetic field vector evaluated at the spacecraft position and expressed in the spacecraft body frame (Tesla). |
| Eclipse Status | Discrete indicator of the spacecraft eclipse state (e.g. illuminated, penumbra, umbra), depending on the selected eclipse model. |
| Eclipse Factor | Continuous factor in the range [0, 1] that scales the solar radiation pressure acting on the spacecraft to account for eclipse conditions. |