org.orekit.forces

Class BoxAndSolarArraySpacecraft

java.lang.Object

org.orekit.forces.BoxAndSolarArraySpacecraft

All Implemented Interfaces:

DragSensitive, RadiationSensitive

public class BoxAndSolarArraySpacecraft
extends Object
implements RadiationSensitive, DragSensitive

Class representing the features of a classical satellite with a convex body shape and rotating flat solar arrays.

The body can be either a simple parallelepipedic box aligned with spacecraft axes or a set of facets defined by their area and normal vector. This should handle accurately most spacecraft shapes.

The solar array rotation with respect to satellite body can be either the best lighting orientation (i.e. Sun exactly in solar array meridian plane defined by solar array rotation axis and solar array normal vector) or a rotation evolving linearly according to a start position and an angular rate (which can be set to 0 for non-rotating panels, which may occur in special modes or during contingencies).

The lift component of the drag force can be optionally considered. It should probably only be used for reentry computation, with much denser atmosphere than in regular orbit propagation. The lift component is computed using a ratio of molecules that experience specular reflection instead of diffuse reflection (absorption followed by outgassing at negligible velocity). Without lift (i.e. when the lift ratio is set to 0), drag force is along atmosphere relative velocity. With lift (i.e. when the lift ratio is set to any value between 0 and 1), the drag force depends on both relative velocity direction and facets normal orientation. For a single panel, if the relative velocity is head-on (i.e. aligned with the panel normal), the force will be in the same direction with and without lift, but the magnitude with lift ratio set to 1.0 will be twice the magnitude with lift ratio set to 0.0 (because atmosphere molecules bounces backward at same velocity in case of specular reflection).

This model does not take cast shadow between body and solar array into account.

Author:

Luc Maisonobe, Pascal Parraud

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BoxAndSolarArraySpacecraft.Facet Class representing a single facet of a convex spacecraft body.

Field Summary

Fields inherited from interface org.orekit.forces.radiation.RadiationSensitive

ABSORPTION_COEFFICIENT, REFLECTION_COEFFICIENT

Fields inherited from interface org.orekit.forces.drag.DragSensitive

DRAG_COEFFICIENT, LIFT_RATIO

Constructor Summary

Constructors

Constructor and Description
BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, AbsoluteDate referenceDate, Vector3D referenceNormal, double rotationRate, double dragCoeff, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with linear rotation of solar array.
BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, AbsoluteDate referenceDate, Vector3D referenceNormal, double rotationRate, double dragCoeff, double liftRatio, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with linear rotation of solar array.
BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, double dragCoeff, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with best lighting of solar array.
BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, double dragCoeff, double liftRatio, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with best lighting of solar array.
BoxAndSolarArraySpacecraft(double xLength, double yLength, double zLength, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, AbsoluteDate referenceDate, Vector3D referenceNormal, double rotationRate, double dragCoeff, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with linear rotation of solar array.
BoxAndSolarArraySpacecraft(double xLength, double yLength, double zLength, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, AbsoluteDate referenceDate, Vector3D referenceNormal, double rotationRate, double dragCoeff, double liftRatio, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with linear rotation of solar array.
BoxAndSolarArraySpacecraft(double xLength, double yLength, double zLength, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, double dragCoeff, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with best lighting of solar array.
BoxAndSolarArraySpacecraft(double xLength, double yLength, double zLength, PVCoordinatesProvider sun, double solarArrayArea, Vector3D solarArrayAxis, double dragCoeff, double liftRatio, double absorptionCoeff, double reflectionCoeff) Build a spacecraft model with best lighting of solar array.

Method Summary

Modifier and Type	Method and Description
Vector3D	dragAcceleration(AbsoluteDate date, Frame frame, Vector3D position, Rotation rotation, double mass, double density, Vector3D relativeVelocity, double[] parameters) Compute the acceleration due to drag.
<T extends CalculusFieldElement<T>> FieldVector3D<T>	dragAcceleration(FieldAbsoluteDate<T> date, Frame frame, FieldVector3D<T> position, FieldRotation<T> rotation, T mass, T density, FieldVector3D<T> relativeVelocity, T[] parameters) Compute the acceleration due to drag.
List<ParameterDriver>	getDragParametersDrivers() Get the drivers for supported parameters.
Vector3D	getNormal(AbsoluteDate date, Frame frame, Vector3D position, Rotation rotation) Get solar array normal in spacecraft frame.
<T extends CalculusFieldElement<T>> FieldVector3D<T>	getNormal(FieldAbsoluteDate<T> date, Frame frame, FieldVector3D<T> position, FieldRotation<T> rotation) Get solar array normal in spacecraft frame.
List<ParameterDriver>	getRadiationParametersDrivers() Get the drivers for supported parameters.
Vector3D	radiationPressureAcceleration(AbsoluteDate date, Frame frame, Vector3D position, Rotation rotation, double mass, Vector3D flux, double[] parameters) Compute the acceleration due to radiation pressure.
<T extends CalculusFieldElement<T>> FieldVector3D<T>	radiationPressureAcceleration(FieldAbsoluteDate<T> date, Frame frame, FieldVector3D<T> position, FieldRotation<T> rotation, T mass, FieldVector3D<T> flux, T[] parameters) Compute the acceleration due to radiation pressure.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(double xLength,
                                  double yLength,
                                  double zLength,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  double dragCoeff,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with best lighting of solar array.

This constructor builds an instance that completely ignores lift in atmospheric drag (the value of lift coefficient is set to zero, and there are no drivers to change it).

Solar arrays orientation will be such that at each time the Sun direction will always be in the solar array meridian plane defined by solar array rotation axis and solar array normal vector.

Parameters:

xLength - length of the body along its X axis (m)

yLength - length of the body along its Y axis (m)

zLength - length of the body along its Z axis (m)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

dragCoeff - drag coefficient (used only for drag)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(double xLength,
                                  double yLength,
                                  double zLength,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  double dragCoeff,
                                  double liftRatio,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with best lighting of solar array.

Solar arrays orientation will be such that at each time the Sun direction will always be in the solar array meridian plane defined by solar array rotation axis and solar array normal vector.

Parameters:

xLength - length of the body along its X axis (m)

yLength - length of the body along its Y axis (m)

zLength - length of the body along its Z axis (m)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

dragCoeff - drag coefficient (used only for drag)

liftRatio - lift ratio (proportion between 0 and 1 of atmosphere modecules that will experience specular reflection when hitting spacecraft instead of experiencing diffuse reflection, hence producing lift)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

Since:

9.0

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  double dragCoeff,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with best lighting of solar array.

The spacecraft body is described by an array of surface vectors. Each facet of the body is described by a vector normal to the facet (pointing outward of the spacecraft) and whose norm is the surface area in m².

Solar arrays orientation will be such that at each time the Sun direction will always be in the solar array meridian plane defined by solar array rotation axis and solar array normal vector.

Parameters:

facets - body facets (only the facets with strictly positive area will be stored)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

dragCoeff - drag coefficient (used only for drag)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  double dragCoeff,
                                  double liftRatio,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with best lighting of solar array.

The spacecraft body is described by an array of surface vectors. Each facet of the body is described by a vector normal to the facet (pointing outward of the spacecraft) and whose norm is the surface area in m².

Solar arrays orientation will be such that at each time the Sun direction will always be in the solar array meridian plane defined by solar array rotation axis and solar array normal vector.

Parameters:

facets - body facets (only the facets with strictly positive area will be stored)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

dragCoeff - drag coefficient (used only for drag)

liftRatio - lift ratio (proportion between 0 and 1 of atmosphere modecules that will experience specular reflection when hitting spacecraft instead of experiencing diffuse reflection, hence producing lift)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

Since:

9.0

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(double xLength,
                                  double yLength,
                                  double zLength,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  AbsoluteDate referenceDate,
                                  Vector3D referenceNormal,
                                  double rotationRate,
                                  double dragCoeff,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with linear rotation of solar array.

Solar arrays orientation will be a regular rotation from the reference orientation at reference date and using a constant rotation rate.

Parameters:

xLength - length of the body along its X axis (m)

yLength - length of the body along its Y axis (m)

zLength - length of the body along its Z axis (m)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

referenceDate - reference date for the solar array rotation

referenceNormal - direction of the solar array normal at reference date in spacecraft frame

rotationRate - rotation rate of the solar array, may be 0 (rad/s)

dragCoeff - drag coefficient (used only for drag)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(double xLength,
                                  double yLength,
                                  double zLength,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  AbsoluteDate referenceDate,
                                  Vector3D referenceNormal,
                                  double rotationRate,
                                  double dragCoeff,
                                  double liftRatio,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with linear rotation of solar array.

Solar arrays orientation will be a regular rotation from the reference orientation at reference date and using a constant rotation rate.

Parameters:

xLength - length of the body along its X axis (m)

yLength - length of the body along its Y axis (m)

zLength - length of the body along its Z axis (m)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

referenceDate - reference date for the solar array rotation

referenceNormal - direction of the solar array normal at reference date in spacecraft frame

rotationRate - rotation rate of the solar array, may be 0 (rad/s)

dragCoeff - drag coefficient (used only for drag)

liftRatio - lift ratio (proportion between 0 and 1 of atmosphere modecules that will experience specular reflection when hitting spacecraft instead of experiencing diffuse reflection, hence producing lift)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

Since:

9.0

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  AbsoluteDate referenceDate,
                                  Vector3D referenceNormal,
                                  double rotationRate,
                                  double dragCoeff,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with linear rotation of solar array.

The spacecraft body is described by an array of surface vectors. Each facet of the body is described by a vector normal to the facet (pointing outward of the spacecraft) and whose norm is the surface area in m².

Solar arrays orientation will be a regular rotation from the reference orientation at reference date and using a constant rotation rate.

Parameters:

facets - body facets (only the facets with strictly positive area will be stored)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

referenceDate - reference date for the solar array rotation

referenceNormal - direction of the solar array normal at reference date in spacecraft frame

rotationRate - rotation rate of the solar array, may be 0 (rad/s)

dragCoeff - drag coefficient (used only for drag)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

BoxAndSolarArraySpacecraft

public BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  Vector3D solarArrayAxis,
                                  AbsoluteDate referenceDate,
                                  Vector3D referenceNormal,
                                  double rotationRate,
                                  double dragCoeff,
                                  double liftRatio,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with linear rotation of solar array.

The spacecraft body is described by an array of surface vectors. Each facet of the body is described by a vector normal to the facet (pointing outward of the spacecraft) and whose norm is the surface area in m².

Solar arrays orientation will be a regular rotation from the reference orientation at reference date and using a constant rotation rate.

Parameters:

facets - body facets (only the facets with strictly positive area will be stored)

sun - sun model

solarArrayArea - area of the solar array (m²)

solarArrayAxis - solar array rotation axis in satellite frame

referenceDate - reference date for the solar array rotation

referenceNormal - direction of the solar array normal at reference date in spacecraft frame

rotationRate - rotation rate of the solar array, may be 0 (rad/s)

dragCoeff - drag coefficient (used only for drag)

liftRatio - lift ratio (proportion between 0 and 1 of atmosphere modecules that will experience specular reflection when hitting spacecraft instead of experiencing diffuse reflection, hence producing lift)

absorptionCoeff - absorption coefficient between 0.0 an 1.0 (used only for radiation pressure)

reflectionCoeff - specular reflection coefficient between 0.0 an 1.0 (used only for radiation pressure)

Since:

9.0

Method Detail

getDragParametersDrivers

public List<ParameterDriver> getDragParametersDrivers()

Get the drivers for supported parameters.

Specified by:

getDragParametersDrivers in interface DragSensitive

Returns:

parameters drivers

getRadiationParametersDrivers

public List<ParameterDriver> getRadiationParametersDrivers()

Get the drivers for supported parameters.

Specified by:

getRadiationParametersDrivers in interface RadiationSensitive

Returns:

parameters drivers

getNormal

public Vector3D getNormal(AbsoluteDate date,
                          Frame frame,
                          Vector3D position,
                          Rotation rotation)

Get solar array normal in spacecraft frame.

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

Returns:

solar array normal in spacecraft frame

getNormal

public <T extends CalculusFieldElement<T>> FieldVector3D<T> getNormal(FieldAbsoluteDate<T> date,
                                                                      Frame frame,
                                                                      FieldVector3D<T> position,
                                                                      FieldRotation<T> rotation)

Get solar array normal in spacecraft frame.

Type Parameters:

T - type of the field elements

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

Returns:

solar array normal in spacecraft frame

dragAcceleration

public Vector3D dragAcceleration(AbsoluteDate date,
                                 Frame frame,
                                 Vector3D position,
                                 Rotation rotation,
                                 double mass,
                                 double density,
                                 Vector3D relativeVelocity,
                                 double[] parameters)

Compute the acceleration due to drag.

The computation includes all spacecraft specific characteristics like shape, area and coefficients.

Specified by:

dragAcceleration in interface DragSensitive

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

mass - current mass

density - atmospheric density at spacecraft position

relativeVelocity - relative velocity of atmosphere with respect to spacecraft, in the same inertial frame as spacecraft orbit (m/s)

parameters - values of the force model parameters

Returns:

spacecraft acceleration in the same inertial frame as spacecraft orbit (m/s²)

radiationPressureAcceleration

public Vector3D radiationPressureAcceleration(AbsoluteDate date,
                                              Frame frame,
                                              Vector3D position,
                                              Rotation rotation,
                                              double mass,
                                              Vector3D flux,
                                              double[] parameters)

Compute the acceleration due to radiation pressure.

Specified by:

radiationPressureAcceleration in interface RadiationSensitive

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

mass - current mass

flux - radiation flux in the same inertial frame as spacecraft orbit

parameters - values of the force model parameters

Returns:

spacecraft acceleration in the same inertial frame as spacecraft orbit (m/s²)

dragAcceleration

public <T extends CalculusFieldElement<T>> FieldVector3D<T> dragAcceleration(FieldAbsoluteDate<T> date,
                                                                             Frame frame,
                                                                             FieldVector3D<T> position,
                                                                             FieldRotation<T> rotation,
                                                                             T mass,
                                                                             T density,
                                                                             FieldVector3D<T> relativeVelocity,
                                                                             T[] parameters)

Compute the acceleration due to drag.

The computation includes all spacecraft specific characteristics like shape, area and coefficients.

Specified by:

dragAcceleration in interface DragSensitive

Type Parameters:

T - instance of a CalculusFieldElement

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

mass - current mass

density - atmospheric density at spacecraft position

relativeVelocity - relative velocity of atmosphere with respect to spacecraft, in the same inertial frame as spacecraft orbit (m/s)

parameters - values of the force model parameters

Returns:

spacecraft acceleration in the same inertial frame as spacecraft orbit (m/s²)

radiationPressureAcceleration

public <T extends CalculusFieldElement<T>> FieldVector3D<T> radiationPressureAcceleration(FieldAbsoluteDate<T> date,
                                                                                          Frame frame,
                                                                                          FieldVector3D<T> position,
                                                                                          FieldRotation<T> rotation,
                                                                                          T mass,
                                                                                          FieldVector3D<T> flux,
                                                                                          T[] parameters)

Compute the acceleration due to radiation pressure.

Specified by:

radiationPressureAcceleration in interface RadiationSensitive

Type Parameters:

T - extends CalculusFieldElement

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

mass - current mass

flux - radiation flux in the same inertial frame as spacecraft orbit

parameters - values of the force model parameters

Returns:

spacecraft acceleration in the same inertial frame as spacecraft orbit (m/s²)