Orbital Event

Script Type: WsfOrbitalEvent

event <event type>
   Event Constraint   …
   finite          ...
   duration        ...
   update_interval ...
   event-specific commands ...
end_event

event … end_event

maneuver … end_maneuver

Specify an event that is to be executed as part of a executed as part of an orbital mission sequence. A constraint can be specified to delay execution of the event. With many events, a specific constraint type is required, but for some other events it is optional. Consult the documentation for each event type for allowed constraints.

Note

Maneuver types can be defined with a maneuver … end_maneuver block.

Available event types are the following

Orbital Maneuver Events:

• Change Eccentricity

• Change Inclination

• Change Right Ascension of Ascending Node (RAAN)

• Change Right Ascension of Ascending Node (RAAN) and Inclination

• Change Semi-Major Axis

• Circularize

• Compound

• Delta_V

• Drift

• Hohmann Transfer

• Intercept

• Match Velocity

• Natural Motion Circumnavigation

• Normal

• Rendezvous

• Tangent

• Target

• Teardrop

Non-Orbital Maneuver Events:

• Change Attitude

• Perform Staging

• Scripted

Common Event Commands

finite

Specify that the event is to be executed over a finite time (i.e., it is non-impulsive).

Note

Individual events may not support finite execution. For example, finite orbital maneuvering is only supported for in-plane maneuvers.

duration

The desired duration of finite events. If no duration is specified, the event will be executed as quickly as possible.

update_interval <time-value>

The update_interval for which finite events are updated.

Default 1.0 s

Event Constraints

execute_at orbit <orbit-num> <constraint>
execute_at                   <constraint>

Specify a constraint determining when at which point in an orbit an event will occur. Normally constraints must be specified for all simple event types (i.e., all but hohmann_transfer, compound, and the top-level mission_sequence events block). Valid constraints vary by event; consult each specific event type for allowed constraints. With the exception of relative_time, these constraints may only be used with bound orbits.

orbit <orbit-num>

Execute the event only after a specified number of orbits have been propagated.

Note

The orbit number constraint is used in combination with another constraint, in order to provide an additional delay in execution. If an event is to be executed as fast as possible, this constraint can be omitted.

<constraint> is one of the following:

relative_time <time-value>

Execute the event at a relative time in the future.

Note

This constraint can be used for non-elliptical orbits, but any orbit number offset will be ignored.

periapsis

apoapsis

Execute the event once the satellite reaches one of the apses (either periapsis or apoapsis).

ascending_node

descending_node

Execute the event once the satellite reaches either the ascending or descending nodes.

ascending_radius <length-value>

descending_radius <length-value>

Execute the event once the satellite reaches the specified radius, and after reaching either the ascending or descending nodes.

Note

These constraints are currently only used with the circularize event.

northern_intersection

southern_intersection

Execute the event once the satellite reaches a event-specific northern latitude intersection or a southern latitude intersection.

Note

These constraints are only used with the change_raan and change_raan_inclination mission events

eclipse_entry

eclipse_exit

Execute the event when the satellite enters or exits earth’s shadow.