ImpulsiveBurn Object

Description

The ImpulsiveBurn is used to provide an instantaneous velocity change to a Spacecraft. See Impulsive Burns for more information.

Inheritance Hierarchy: Object->ThrustEvent->Burn->ImpulsiveBurn

Available In Editions:

Engineer

Mission

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.

Properties

Name	Description	Attributes
AttitudeSystem	Determines the attitude frame in which the Impulsive Burn will be applied to the spacecraft.	Type: Variable Access: Read/Write
BurnDirection	The components of the thrust vector in the coordinates of the attitude system specified by the chosen AttitudeSystem.	Type: Array Access: Read/Write Units: km/s
DeclaredName	The name of the object as declared.	Type: String Access: Read-Only
ExecutionPhase	Reveals which portion of the event sequence is currently executing.	Type: Variable Access: Read-Only
ManeuverGravityConstant	The value of the gravitational acceleration at the surface of the Earth. Used in the conversion of specific impulse (Isp) between English and MKS units. The default value is 9.81 m/s^2 but can be adjusted to the value adopted by the thruster manufacturer. Used for mass depletion.	Type: Variable Access: Read/Write Units: m/s^2
ManeuverOffsetTime	The offset time from current Spacecraft epoch, to apply the maneuver. The Spacecraft will be propagated to the offset time. A negative offset time can be used.	Type: Variable Access: Read/Write Units: s
Name	The name displayed for this object in output windows such as views, plots, and reports.	Type: String Access: Read/Write
ObjectId	The unique identifier for the object.	Type: Variable Access: Read-Only
ObjectType	The type of the object.	Type: String Access: Read-Only
OD	This property contains the OD settings for all the ImpulsiveBurn properties that can be estimated.	Type: ImpulsiveBurnODProperties Access: Read-Only
SpecificImpulse	The specific impulse (Isp) used for mass depletion.	Type: Variable Access: Read/Write Units: s
ThrustScaleFactor	The overall thrust scale factor for the maneuver. This property is ignored for Impulsive Burns.	Type: Variable Access: Read/Write

Methods

Name	Description
ClearSavedStates	Clears previous saved states for this object.
GetFromFile	Load the object state from the specified FreeFlyer object file.
GetFromString	Load the object state from the specified string.
PutToFile	Convert the object state to FreeFlyer object xml and write to a file.
PutToString	Convert the object state to FreeFlyer object xml and return as a string.
ReferenceEquals	Returns 1 if the argument refers to the calling object and 0 otherwise.
Restore	Restore an object's state from a previously saved state.
Save	Save the object's state so that it can be restored later.

Deprecated Properties

Name

Description

Attributes

BurnDuration

This property is ignored for Impulsive Burns.

This property has been Deprecated. Please use the FiniteBurn Object to model finite burns.

Type: Variable

Access: Read/Write

Units: s

ManeuverStartTime

The offset time from current Spacecraft epoch, to apply the maneuver. The Spacecraft will be propagated to the offset time. A negative offset time can be used.

This property has been Deprecated. Please use ManeuverOffsetTime instead.

Type: Variable

Access: Read/Write

Units: s

X_Component

For AttitudeSystem = 0, ICRF X-directed unit vector component of the maneuver.

For AttitudeSystem = 1, Velocity directed unit vector component of the maneuver.

For AttitudeSystem = 2, Co-Velocity directed unit vector component of the maneuver.

For AttitudeSystem = 3, the Spacecraft's attitude is adjusted so that Spacecraft.EulerAngle1 is temporarily set to the value specified by FiniteBurn.X_Component for the duration of the maneuver. The Euler angle is evaluated in degrees and is referenced to the Spacecraft's attitude reference frame. The Euler Sequence used by the FiniteBurn object is defined by the Spacecraft object's Euler Sequence. Individual thruster orientations defined in the Thruster object(s) are used for directing delta-v.

For AttitudeSystem = 4, Y cross Z directed unit vector component of the maneuver.

For AttitudeSystem = 5, Position directed component of the maneuver.

This property has been Deprecated. Please use the BurnDirection vector instead.

Type: Variable

Access: Read/Write

Units: km/s

Y_Component

For AttitudeSystem = 0, ICRF Y-directed unit vector component of the maneuver.

For AttitudeSystem = 1, Orbit Normal directed unit vector component of the maneuver.

For AttitudeSystem = 2, Negative Orbit Normal directed unit vector component of the maneuver.

For AttitudeSystem = 3, the Spacecraft's attitude is adjusted so that Spacecraft.EulerAngle2 is temporarily set to the value specified by FiniteBurn.Y_Component for the duration of the maneuver. The Euler angle is evaluated in degrees and is referenced to the Spacecraft's attitude reference frame. The Euler Sequence used by the FiniteBurn object is defined by the Spacecraft object's Euler Sequence. Individual thruster orientations defined in the Thruster object(s) are used for directing delta-v.

For AttitudeSystem = 4, Negative Orbit Normal directed unit vector component of the maneuver.

For AttitudeSystem = 5, Velocity directed component of the maneuver.

This property has been Deprecated. Please use the BurnDirection vector instead.

Type: Variable

Access: Read/Write

Units: km/s

Z_Component

For AttitudeSystem = 0, ICRF Z-directed unit vector component of the maneuver.

For AttitudeSystem = 1, Orbit Bi-Normal directed unit vector component of the maneuver.

For AttitudeSystem = 2, Nadir directed unit vector component of the maneuver.

For AttitudeSystem = 3, the Spacecraft's attitude is adjusted so that Spacecraft.EulerAngle3 is temporarily set to the value specified by FiniteBurn.Z_Component for the duration of the maneuver. The Euler angle is evaluated in degrees and is referenced to the Spacecraft's attitude reference frame. The Euler Sequence used by the FiniteBurn object is defined by the Spacecraft object's Euler Sequence. Individual thruster orientations defined in the Thruster object(s) are used for directing delta-v.

For AttitudeSystem = 4, Intersection Normal to the Earth's Surface directed unit vector component of the maneuver.

For AttitudeSystem = 5, Orbit Normal directed component of the maneuver.

This property has been Deprecated. Please use the BurnDirection vector instead.

Type: Variable

Access: Read/Write

Units: km/s