Spacecraft.PenumbralShadowTimes(Array, Array) Method

 Top 

Description

Determines the entry time, exit time, and duration of a Spacecraft's pass through the shadow of the spacecraft's central body.

 

The shadow times are determined using a conical shadow. The three regions of the Spacecraft's central body's shadow, the umbra, penumbra, and annular, are shown in the diagram below. Events are reported for prenumbral shadow conditions only.

 

The three regions of the Spacecraft's central body's shadow.

The three regions of the Spacecraft's central body's shadow.

 

Note: This method uses a spherical model for the occulting body. Use the options available in the VisibilityCalculator to exercise more control over the analysis.

 

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.PenumbralShadowTimes(

Array EventTime,

Array EventType)

 

 

Arguments

EventTime

Description:

The time that the event occurred.

 

The FF_Preferences.IntervalEventReportingBehavior property controls whether the start of propagation is reported as an event. By default, if the time in shadow starts before the beginning of the propagation span, FreeFlyer will label the start of the propagation as the start of the time in shadow.

 

 

EventType

Description:

The type of the event that occurred. Event type == 201 is entry into penumbral shadow. Event type == 202 is exit from penumbral shadow.

 

 

 

Return Value

Type:

number

 

 

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

 

Syntax

myVariable1 = mySpacecraft1.PenumbralShadowTimes(myArray1, myArray2);

 

 

Example 1

This example demonstrates how to generate a report of a Spacecraft's passes through its central body's penumbral shadow.

 

Spacecraft Spacecraft1;

Variable i;

Variable shadowTimes;

Array EventTime;

Array EventType;

String scEventType;

String scEventTime;

DataTableWindow scReport({scEventType, scEventTime}, 0);

 

While (Spacecraft1.ElapsedDays < 1);

 

          shadowTimes = Spacecraft1.PenumbralShadowTimes(EventTime, EventType);

 

          If(shadowTimes > 0) then;

                      For i = 0 to shadowTimes-1 step 1;

                                  Switch (EventType[i]);

                                              Case 201:

                                                          scEventType = "Entry into Penumbral Shadow: ";

                                                          scEventTime = EventTime[i].EpochFormat;

                                                          Update scReport;

                                                          Break;

                                              Case 202:

                                                          scEventType = "Exit from Penumbral Shadow: ";

                                                          scEventTime = EventTime[i].EpochFormat;

                                                          Update scReport;

                                  End;

                      End;

          End;

 

          Step Spacecraft1;

 

End;

 

 

Output:

 

scEventType

scEventTime

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Entry into Penumbral Shadow:

Exit from Penumbral Shadow:

Jan 01 2020 00:00:00.000

Jan 01 2020 00:07:03.192

Jan 01 2020 01:11:50.815

Jan 01 2020 01:45:59.765

Jan 01 2020 02:50:47.313

Jan 01 2020 03:24:56.337

Jan 01 2020 04:29:43.812

Jan 01 2020 05:03:52.910

Jan 01 2020 06:08:40.458

Jan 01 2020 06:42:49.554

Jan 01 2020 07:47:37.104

Jan 01 2020 08:21:46.273

Jan 01 2020 09:26:33.823

Jan 01 2020 10:00:42.992

Jan 01 2020 11:05:30.394

Jan 01 2020 11:39:39.638

Jan 01 2020 12:44:26.820

Jan 01 2020 13:18:36.136

Jan 01 2020 14:23:23.320

Jan 01 2020 14:57:32.636

Jan 01 2020 16:02:19.892

Jan 01 2020 16:36:29.281

Jan 01 2020 17:41:16.464

Jan 01 2020 18:15:25.854

Jan 01 2020 19:20:13.036

Jan 01 2020 19:54:22.500

Jan 01 2020 20:59:09.682

Jan 01 2020 21:33:19.144

Jan 01 2020 22:38:06.254

Jan 01 2020 23:12:15.863

 

 

 

See also

Spacecraft Object

Spacecraft.PenumbralShadowTimes

Spacecraft Propagation Guide

Coverage and Contact Analysis Guide