Spacecraft.CardinalPoints(CelestialObject, Array, Array) Method

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Description

Returns the times when the Spacecraft is at each of the cardinal points. The cardinal point calculations are based on the alpha angle, which is the angle between the Spacecraft's position and the target CelestialObjects's position with respect to the Spacecraft's central body when both vectors are projected onto the Spacecraft's orbit plane. Note that the target CelestialObject is modeled as a point.

The mathematical definition of the alpha angle is:

Below is a diagram depicting how the alpha angle is defined:

A visual representation of the Alpha angle.

Timing Precision Mode

This page describes functionality in millisecond timing precision mode. Millisecond timing precision mode is deprecated and will be removed in a future release. We recommend that you migrate your Mission Plans to nanosecond timing precision mode.

Click here to see the documentation for this object in nanosecond timing precision mode.

Note: This is an interval method. See the Interval Methods page for more information.

Note: This method has a state. See the Methods and Properties with State page for more information.

Method Signature

Spacecraft.CardinalPoints(	CelestialObject target,
	Array EventTime,
	Array EventType)

Arguments

target
Description:	The target CelestialObject to be used in the CardinalPoint calculations. If no CelestialObject is specified, the Sun will be used.

EventTime
Description:	The time that the event occurred.

EventType

Description:

The type of the event that occurred.

Event Type == 1 is noon (alpha angle = 0).

Event Type == 2 is dusk (alpha angle = 90).

Event Type == 3 is midnight (alpha angle = 180).

Event Type == 4 is dawn (alpha angle = 270).

Return Value

Type:

number

Returns the number of elements filled into EventType and EventTime arrays.

Syntax

myVariable1 = mySpacecraft1.CardinalPoints(myCelestialObject1, myArray1, myArray2);