org.orekit.forces
Class BoxAndSolarArraySpacecraft

java.lang.Object
  org.orekit.forces.BoxAndSolarArraySpacecraft

All Implemented Interfaces:

java.io.Serializable, DragSensitive, RadiationSensitive

public class BoxAndSolarArraySpacecraft
extends java.lang.Object
implements RadiationSensitive, DragSensitive

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

As of 5.0, this class is still considered experimental, so use it with care.

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 lightning 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).

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

Instances of this class are guaranteed to be immutable.

Version:

$Revision: 3197 $ $Date: 2010-04-28 10:39:09 +0200 (mer. 28 avril 2010) $

Author:

Luc Maisonobe, Pascal Parraud

See Also:

SphericalSpacecraft, Serialized Form

Nested Class Summary

static class

BoxAndSolarArraySpacecraft.Facet Class representing a single facet of a convex spacecraft body.

Constructor Summary

BoxAndSolarArraySpacecraft(BoxAndSolarArraySpacecraft.Facet[] facets, PVCoordinatesProvider sun, double solarArrayArea, org.apache.commons.math.geometry.Vector3D solarArrayAxis, AbsoluteDate referenceDate, org.apache.commons.math.geometry.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, org.apache.commons.math.geometry.Vector3D solarArrayAxis, double dragCoeff, double absorptionCoeff, double reflectionCoeff)
Build a spacecraft model with best lightning of solar array.

BoxAndSolarArraySpacecraft(double xLength, double yLength, double zLength, PVCoordinatesProvider sun, double solarArrayArea, org.apache.commons.math.geometry.Vector3D solarArrayAxis, AbsoluteDate referenceDate, org.apache.commons.math.geometry.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, org.apache.commons.math.geometry.Vector3D solarArrayAxis, double dragCoeff, double absorptionCoeff, double reflectionCoeff)
Build a spacecraft model with best lightning of solar array.

Method Summary

org.apache.commons.math.geometry.Vector3D	dragAcceleration(SpacecraftState state, double density, org.apache.commons.math.geometry.Vector3D relativeVelocity) Compute the acceleration due to drag.
double	getAbsorptionCoefficient() Get the absorption coefficient.
double	getDragCoefficient() Get the drag coefficient.
org.apache.commons.math.geometry.Vector3D	getNormal(SpacecraftState state) Get solar array normal in spacecraft frame.
double	getReflectionCoefficient() Get the specular reflection coefficient.
org.apache.commons.math.geometry.Vector3D	radiationPressureAcceleration(SpacecraftState state, org.apache.commons.math.geometry.Vector3D flux) Compute the acceleration due to radiation pressure.
void	setAbsorptionCoefficient(double value) Set the absorption coefficient.
void	setDragCoefficient(double value) Set the drag coefficient.
void	setReflectionCoefficient(double value) Set the specular reflection coefficient.

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,
                                  org.apache.commons.math.geometry.Vector3D solarArrayAxis,
                                  double dragCoeff,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with best lightning 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)

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,
                                  org.apache.commons.math.geometry.Vector3D solarArrayAxis,
                                  double dragCoeff,
                                  double absorptionCoeff,
                                  double reflectionCoeff)

Build a spacecraft model with best lightning of solar array.

The spacecraft body is described by an array of surface vectors. Each facet of the body is describe 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(double xLength,
                                  double yLength,
                                  double zLength,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  org.apache.commons.math.geometry.Vector3D solarArrayAxis,
                                  AbsoluteDate referenceDate,
                                  org.apache.commons.math.geometry.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(BoxAndSolarArraySpacecraft.Facet[] facets,
                                  PVCoordinatesProvider sun,
                                  double solarArrayArea,
                                  org.apache.commons.math.geometry.Vector3D solarArrayAxis,
                                  AbsoluteDate referenceDate,
                                  org.apache.commons.math.geometry.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 describe 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)

Method Detail

getNormal

public org.apache.commons.math.geometry.Vector3D getNormal(SpacecraftState state)
                                                    throws OrekitException

Get solar array normal in spacecraft frame.

Parameters:

state - current state information: date, kinematics, attitude

Returns:

solar array normal in spacecraft frame

Throws:

OrekitException - if sun direction cannot be computed in best lightning configuration

dragAcceleration

public org.apache.commons.math.geometry.Vector3D dragAcceleration(SpacecraftState state,
                                                                  double density,
                                                                  org.apache.commons.math.geometry.Vector3D relativeVelocity)
                                                           throws OrekitException

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:

state - current state information: date, kinematics, attitude

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)

Returns:

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

Throws:

OrekitException - if acceleration cannot be computed

radiationPressureAcceleration

public org.apache.commons.math.geometry.Vector3D radiationPressureAcceleration(SpacecraftState state,
                                                                               org.apache.commons.math.geometry.Vector3D flux)
                                                                        throws OrekitException

Compute the acceleration due to radiation pressure.

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

Specified by:

radiationPressureAcceleration in interface RadiationSensitive

Parameters:

state - current state information: date, kinematics, attitude

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

Returns:

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

Throws:

OrekitException - if acceleration cannot be computed

setAbsorptionCoefficient

public void setAbsorptionCoefficient(double value)

Set the absorption coefficient.

Specified by:

setAbsorptionCoefficient in interface RadiationSensitive

Parameters:

value - absorption coefficient

getAbsorptionCoefficient

public double getAbsorptionCoefficient()

Get the absorption coefficient.

Specified by:

getAbsorptionCoefficient in interface RadiationSensitive

Returns:

absorption coefficient

setReflectionCoefficient

public void setReflectionCoefficient(double value)

Set the specular reflection coefficient.

Specified by:

setReflectionCoefficient in interface RadiationSensitive

Parameters:

value - specular reflection coefficient

getReflectionCoefficient

public double getReflectionCoefficient()

Get the specular reflection coefficient.

Specified by:

getReflectionCoefficient in interface RadiationSensitive

Returns:

reflection coefficient

setDragCoefficient

public void setDragCoefficient(double value)

Set the drag coefficient.

Specified by:

setDragCoefficient in interface DragSensitive

Parameters:

value - drag coefficient

getDragCoefficient

public double getDragCoefficient()

Get the drag coefficient.

Specified by:

getDragCoefficient in interface DragSensitive

Returns:

drag coefficient