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ASTRIUMSpace Transportation

ASCENTIS: Planetary Ascent

Vehicle FES Tool

Eugénio Ferreira, Thierry Jean-Marius

ASTRIUM Space Transportation

Mission analysis & GNC teams

3rd International Workshop on Astrodynamics Tools and TechniquesESTEC, 4 October 2006

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3rd Intl Workshop onAstrodynamics Tools & Techniques

2-5 October 2006

ASTRIUMSpace TransportationOutline

• Simulation Tool objectives

• Architecture and models

• Simulator usage

• Simulation outcomes

• Conclusion

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3rd Intl Workshop onAstrodynamics Tools & Techniques

2-5 October 2006

ASTRIUMSpace TransportationASCENTIS objectives

• Developed within ESA TRP “PAV GNC”in partnership with Scisys

• Assess concept performances during ascent

– GNC algorithms integrated in closed loop

– Validation of GNC architecture & coupling effects

• 6-dof Non Real Time platform, built on Matlab/Simulink

– Representative: involves deviations on both vehicle & environment

– Operating modes: unitary cases / Monte-Carlo analysis

– Modular and expandable, Graphical User Interface

• Based on ATPE framework

– Compatible with Real Time environment, existing Library modules used

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationConsidered Missions & Vehicles

• Mars ascent phase, up to circular orbit

– 3 boosted phases

– 1 long coasting phase, before circularisation

– Mars Sample Return

· 500 km circular orbit

· 2-stages, liquid

– Mars Manned Mission

· 15 000 km circular orbit

· 1½-stage, liquid

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3rd Intl Workshop onAstrodynamics Tools & Techniques

2-5 October 2006

ASTRIUMSpace TransportationTop Level Architecture of the FES

GNC

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationFES models – Spacecraft

• Propulsion

– Engine Management

– Attitude Control System

– Thrust Vector Control

• Aerodynamics

– Each stage modelled

• Mass and Inertia Evolution

– Centring and Inertia

– Fuel Sloshing

– Mass Evolution

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationFES models – Dynamics & Environment

• 6-dof Dynamics

– Translational Dynamics

– Rotational Dynamics

• Mars Gravity Model

– Simple 3rd order

– Complex nth order gravitational

harmonics based on JPL50c

• Mars atmosphere Model

– Look-up tables from EMCD 3.1

– EMCD 3.1 interface directly

embedded in FES

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3rd Intl Workshop onAstrodynamics Tools & Techniques

2-5 October 2006

ASTRIUMSpace TransportationFES models – Sensors

• Inertial Measurement Unit

– 3-axis accelerometer

– 3-axis gyrometer

– Alignment Matrix

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationFES generic models management

• Ascent profile induces required dedicated management

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationFES models – GNC

• GNC algorithms

– Alignement/Navigation

· Inertial

· Coast arcs

– Ascent Guidance

trades-off

· Linear tg

· Pred-cor

· F(vel)

– Ascent Control

· Hinf

· LQG

· Eigen value placement

• C-coded S-functions

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3rd Intl Workshop onAstrodynamics Tools & Techniques

2-5 October 2006

ASTRIUMSpace TransportationGNC sequencing example

1st Stage2nd Stage

1st Boost 2nd Boost Coasting phase 3rd Boost Coasting phase

Navigation

Guidance

TVC control

Roll control

Attitude control

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationASCENTIS usage

• Two ways to run Simulator:

– Command Line

· Simple init., navigate to simulator directory &

edit set of scripts that manages simulation

· Plot and analyse results using command line

plotting functions

– GUI

· Manages scripts in one place

· Gives selections of mission

· Loads mission specific files editing

· User may execute simulations

· Status displayed in command window

· Default plotting at the touch of a button

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationFES use example: Guidance trade-off

• Algorithms comparison through performance index

1.7 m/s98.8%Explicit

66.7 m/s86.2%Predictor-corrector

48.2 m/s18.5%Implicit

95% value20 m/s

requirementGuidance scheme

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace TransportationASCENTIS plots

• Default plots run from single script

• Script manages plotting functions, additional plotting can be added if desired

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace Transportation

Orbital elements@ injection

+ GuidanceX Navigation

ASCENTIS plots: Monte-Carlo (1/2)

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3rd Intl Workshop onAstrodynamics Tools & Techniques

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ASTRIUMSpace Transportation

Q.ααααenvelope

Deflectionenvelope

ASCENTIS plots: Monte-Carlo (2/2)

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3rd Intl Workshop onAstrodynamics Tools & Techniques

2-5 October 2006

ASTRIUMSpace TransportationConclusion

• ASCENTIS is a standalone platform, compatible

with both UNIX & WINDOWS environments

• Fully tested and validated, and RT compliant

• Easy to use interface GUI or Command driven

• Useful platform to assess performances for aPlanetary ascent phase