Booster External Acceleration. More...

Classes
class	Stage
	Utility class to bundle together the attributes for a rocket stage. Some redundancy (payload and dry mass). More...

Public Types
enum	Steering { LINEAR_TANGENT_EC , MANUAL_VEC , MANUAL_PITCH , PITCH_TABLE , UNUSED }

Static Public Member Functions
static int	ActiveStageReadback (double3[] data)

static void	AutoStageSet (double3[] data, bool enabled)
	Set the auto-stage control bit in the booster data block to indicated the value of the enabled parameter.

static void	EnabledSet (double3[] data, bool enabled)
	Set the ENABLED flag in the data block.

static double	FuelReadout (double3[] data, int stageReq=-1)
	Get fuel for the designated stage. If the stage is -1, this is a request for the active stage.

static double3[]	LinearTangentECAlloc (double theta0Deg, int numStages)
	Create data[] array for a linear tangent steering law of the form tan(theta) = (1-t/t_f) tan(theta0) as found in (6.59) of "Design of Rockets and Launch Vehicles", Edberg & Cpsta, AIAA Press.

static double3[]	ManualPitchAlloc (double pitchRad, int numStages)
	Allocate a data block with numStages that will use a manual pitch value for ascent guidance.

static void	ManualPitchUpdate (double pitchRad, double3[] data)

static double3[]	ManualVecAlloc (double3 thrustDir, int numStages)
	Full manual control with acceleration explicitly specified.

static void	ManualVecSetThrustDir (double3[] data, double3 thrustDir)

static void	PayloadCompute (double3[] data, double payloadMassKg)
	Compute and configure the per stage payload values for each stage in a multi-stage booster. e.g. 3 stages: 0, 1, 2 Stage 2 has a payload mass of payloadMassKg. Stage 1 has a payload mass of playloadMassKg + stage2 (fuel + dry mass) Stage 0 has a payload mass of stage 1 payload mass + stage1 (fuel + dry mass)

static double	PayloadReadout (double3[] data, int stageNum)

static double	PitchFromTable (NativeArray< double3 > data, double t, int steering_base)
	Look up the entry in the pitch table. Assume the pitch table might not be regular and that since we're integrating time will advance forward monotonically. Just walk the table to find an entry but keep track of where we were.

static double	PitchReadback (double3[] data)

static double3[]	PitchTableAlloc (double3[] pitchTable, int numStages)

static void	StageSetup (double3[] data, int stageNum, Stage stage)
	Add a stage to the Booster. This assumes data[] has been created with the correct number of total stages, prior to using this method to fill in the details.

static void	SteeringPlaneSet (double3[] data, double3 orbitCenter, double3 orbitNormal)

static void	SteeringTimesSet (double3[] data, double tStartSec, double tEndSec)

static void	ThrottleSet (double3[] data, double throttle)

static int	ThrustAndSteering (ref ExternalAccel.EAStateData eaState, ref ExternalAccel.EADesc eaDesc, double t, double dt, double3 a_in, NativeArray< double3 > data, out double3 a_out, double scaleTtoSec, double scaleAccelSitoGE)
	Static method to run the thrust and do steering calculations for a multi-stage booster. The operational parameters for the engine are contained in the the data[] block. This is interpreted based on the type of booster and steering law configured when initializing the data block.

Static Public Attributes
const int	AUTO_STAGE = 1 << 1

const int	ENABLED = 1 << 0

const int	FUEL_OUT = 1 << 0

const int	SEND_EVENTS = 1 << 2

const int	STAGED = 1 << 1

const int	STATUS_FUEL_OUT = 1

const int	STATUS_STAGED = 2

Detailed Description

Booster External Acceleration.

This class provides the external acceleration of a multi-stage booster. It will be called for each timestep in the numerical integration.

This implementation supports:

multiple stages that (may) reduce the mass of the booster as time goes on (i.e. rocket equation stuff)
a choice of steering laws for the direction of the thrust: manual vector, manual pitch in a target plane, tangent steering in target plance etc.

Booster setup allocates a block of double3[] to hold the state information required for the stages and steering.

Member Function Documentation

◆ AutoStageSet()

static void GravityEngine2.Booster.AutoStageSet	(	double3[]	data,
		bool	enabled )

static

Set the auto-stage control bit in the booster data block to indicated the value of the enabled parameter.

Parameters

data
enabled

◆ EnabledSet()

static void GravityEngine2.Booster.EnabledSet	(	double3[]	data,
		bool	enabled )

static

Set the ENABLED flag in the data block.

Parameters

data
enabled

◆ FuelReadout()

static double GravityEngine2.Booster.FuelReadout	(	double3[]	data,
		int	stageReq = -1 )

static

Get fuel for the designated stage. If the stage is -1, this is a request for the active stage.

Parameters

data
stage	0 based stage number

Returns

◆ LinearTangentECAlloc()

static double3[] GravityEngine2.Booster.LinearTangentECAlloc	(	double	theta0Deg,
		int	numStages )

static

Create data[] array for a linear tangent steering law of the form tan(theta) = (1-t/t_f) tan(theta0) as found in (6.59) of "Design of Rockets and Launch Vehicles", Edberg & Cpsta, AIAA Press.

This uses a standard rocket equation data block but note that if the engine is throttled down the algorithm will still assume the same t_burn and compute the guidance accordingly.

SB = Steering Base [SB0] (law, t_start, t_end) start/end are for overall flight path for steering laws that use this [SB1] center [SB2] plane [SB3] (tan(theta0), 0, pitch_readback)

Parameters

theta0Deg
t_final

Returns

◆ ManualPitchAlloc()

static double3[] GravityEngine2.Booster.ManualPitchAlloc	(	double	pitchRad,
		int	numStages )

static

Allocate a data block with numStages that will use a manual pitch value for ascent guidance.

This adds a single double3 to the standard header + stages that contains: (SE = end of stage block + 1) data[SE+0].x = manual pitch value

Parameters

pitchRad
numStages

Returns

◆ ManualVecAlloc()

static double3[] GravityEngine2.Booster.ManualVecAlloc	(	double3	thrustDir,
		int	numStages )

static

Full manual control with acceleration explicitly specified.

Atypical since does not have any stages or standard steering plane info. [SB0] (law, 0, 0) [SB1] thrustDir

Parameters

thrustDir thrust direction vector (normalized)

Returns

◆ PayloadCompute()

static void GravityEngine2.Booster.PayloadCompute	(	double3[]	data,
		double	payloadMassKg )

static

Compute and configure the per stage payload values for each stage in a multi-stage booster. e.g. 3 stages: 0, 1, 2 Stage 2 has a payload mass of payloadMassKg. Stage 1 has a payload mass of playloadMassKg + stage2 (fuel + dry mass) Stage 0 has a payload mass of stage 1 payload mass + stage1 (fuel + dry mass)

Parameters

data
payloadMassKg

◆ PitchFromTable()

static double GravityEngine2.Booster.PitchFromTable	(	NativeArray< double3 >	data,
		double	t,
		int	steering_base )

static

Look up the entry in the pitch table. Assume the pitch table might not be regular and that since we're integrating time will advance forward monotonically. Just walk the table to find an entry but keep track of where we were.

(Public so Unit tests can find it)

Parameters

data
t
b

Returns

◆ StageSetup()

static void GravityEngine2.Booster.StageSetup	(	double3[]	data,
		int	stageNum,
		Stage	stage )

static

Add a stage to the Booster. This assumes data[] has been created with the correct number of total stages, prior to using this method to fill in the details.

The mass of the payload should include the mass of all higher stages + fuel. This can be calculated automatically by using the utility PayloadCompute().

Parameters

data	data block for the booster
stageNum	number of this stage (0 based)
stage	struct with details of this stage
throttle	throttle value

◆ ThrustAndSteering()

static int GravityEngine2.Booster.ThrustAndSteering	(	ref ExternalAccel::EAStateData	eaState,
		ref ExternalAccel::EADesc	eaDesc,
		double	t,
		double	dt,
		double3	a_in,
		NativeArray< double3 >	data,
		out double3	a_out,
		double	scaleTtoSec,
		double	scaleAccelSitoGE )

static

Static method to run the thrust and do steering calculations for a multi-stage booster. The operational parameters for the engine are contained in the the data[] block. This is interpreted based on the type of booster and steering law configured when initializing the data block.

Parameters

eaState
eaDesc
t
dt
a_in
data
a_out

Returns

The documentation for this class was generated from the following file:

ge2/GE2/Assets/GravityEngine2/Runtime/Core/ExternalAcceleration/Booster.cs

Classes

Public Types

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Function Documentation

◆ AutoStageSet()

◆ EnabledSet()

◆ FuelReadout()

◆ LinearTangentECAlloc()

◆ ManualPitchAlloc()

◆ ManualVecAlloc()

◆ PayloadCompute()

◆ PitchFromTable()

◆ StageSetup()

◆ ThrustAndSteering()