Summary

Stores information about a particular meteoroid, most importantly its orbital elements. Also conducts calculations that convert orbital elements to a Cartesian (x,y,z) position.

List of Functions

Public Global Variables

void setConstants()
void setM0(double nu0)
void calculateCrashPosition(double nu0)
Vector3 getPositionAt(double JDay)
double calculateE(double e, double M)
string setInfoText()
void setInfoText(string inInfoText)
double toRadians(double degree)
double toDegrees(double radian)

Public Global Variables

DateHelper helper

Reference to DateHelper script for help with the conversion of Julian Day (JD) to Gregorian Date in setInfoText()

double[] elements = new double[6]

The meteoroid's 6 orbital elements at time of detection/crash.

double M0

The meteoroid's mean anomaly at time of detection/crash (degrees).

double nu0

The meteoroid's true anomaly at time of detection/crash (degrees).

double A, B, C, a, b, c

Constants of a meteoroid's orbit. Calculated from three of the orbital elements.

float plotScale

The scale of the Unity scene (1 AU = ? metres). Need this for calculating worldspace positions.

double dayDetected

The JD of the meteoroid's impact with Earth.

bool landed

Tells program if meteoroid has landed or not (utilised in BodyPlotter).

Vector3 crashPosition

The Cartesian coordinates of the meteoroid's crash.

Vector3[] positions

An array of every position this meteoroid will every occupy for the duration of the game at one-day increments.

Material lineMaterial

Coloured material to give to the orbit lines.

int trailLength

Number of points in the meteoroid's trail.

string infoText

A (very long) string that contains all information about this meteoroid, to be displayed in the 'info panel' in ScreenMaster.

float period

For infoText. The time it takes for this meteoroid to complete one orbit around the sun in days.

float burnDuration

For infoText. The time in seconds that the meteor was visible in the atmosphere.

float mass

For infoText. The mass of the meteoroid in kilograms.

float massError

For infoText. The uncertainty in the meteoroid's mass (kilograms).

float numDataPts

The number of data points that the DFN have on the path of this meteoroid.

float numCameras

The number of DFN cameras that recorded this meteoroid's path through the atmosphere.

void setConstants()

Initialises the constants A, B, C, a, b & c, which are characteristic of a meteoroid's orbit shape. This is executed once before the program begins.

Params

None (uses orbital elements in elements)

Returns

None

Calls

• toRadians(double degrees)

Called By

• BodyPlotter.makeMeteoroids()

void setM0(double nu0)

Converts the true anomaly at time of detection (nu0) to the mean anomaly at time of detection (M0).

Params

Name	Type	Description
nu0	double	The true anomaly at time of detection (degrees).

Returns

None

Calls

• toRadians(double degrees)
• toDegrees(double radian)

Called By

• BodyPlotter.makeMeteoroids()

void calculateCrashPosition(double nu0)

Calculates the position of the meteoroid at time of detection. Uses almost exactly the same method as in getPositionAt(), but we can bypass the calculation of nu because we're given nu0 in the CSV file.

Params

Name	Type	Description
nu0	double	The true anomaly at time of detection (degrees).

Returns

None

Calls

• toRadians(double degree)

Called By

• BodyPlotter.makeMeteoroids()

Vector3 getPositionAt(double JDay)

Calculates the position of the meteoroid at the imported Julian Day (JD) based on orbital elements and the constants A, B, C, a, b & c.

Method used is from Astronomical Algorithms 2nd ed. by Jean Meeus (p227).

Params

Name	Type	Description
JDay	double	The date (in JD) that we must calculate the position at.

Returns

Name	Type	Description
position	Vector3	The position of the meteoroid in Cartesian (x,y,z) format.

Calls

• calculateE(double e, double M)
• toRadians(double degree)

Called By

• BodyPlotter.makeMeteoroids()
• BodyPlotter.updateMeteoroids()
• BodyPlotter.createLine(GameObject body, string type)
• BodyPlotter.skipToDay(double newJD)

double calculateE(double e, double M)

Calculates the eccentric anomaly (E) based on a planet's eccentricity (e) and mean anomaly (M).

Params

Name	Type	Description
e	double	Eccentricity (unitless).
M	double	Mean anomaly (degrees).

Returns

Name	Type	Description
E	double	Eccentric anomaly (degrees).

Calls

• toDegrees(double radian)
• toRadians(double degree)

Called By

• getPositionAt(double JDay)

string setInfoText()

void setInfoText(string inInfoText)

Uses values already stored in the script to construct the infoText string.

TO DO: include picture of a meteoroid's info panel.

Params

None

Returns

None

Calls

• DateHelper.JDToDateString(double JD)

Called By

• BodyPlotter.makePlanets()

double toRadians(double degree)

Converts an imported angle (degrees) to radians.

Params

Name	Type	Description
degree	double	Angle to convert (degrees).

Returns

Name	Type	Description
NA	double	Converted angle (radians).

Calls

None

Called By

• setConstants()
• setM0(double nu0)
• calculateCrashPosition(double nu0)
• getPositionAt(double JDay)
• calculateE(double e, double M)

double toDegrees(double radian)

Converts an imported angle (radians) to degrees.

Params

Name	Type	Description
radian	double	Angle to convert (radians).

Returns

Name	Type	Description
NA	double	Converted angle (degrees).

Calls

None

Called By

• setM0(double nu0)
• calculateE(double e, double M)