ASCENTIS: Planetary Ascent Vehicle FES Tool Eugénio Ferreira, Thierry Jean-Marius Mission analysis & GNC teams 3rd International Workshop on Astrodynamics Tools and Techniques ESTEC, 4 October 2006 Page 1
Outline Simulation Tool objectives Architecture and models Simulator usage Simulation outcomes Conclusion Page 2
ASCENTIS 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 Page 3 Based on ATPE framework Compatible with Real Time environment, existing Library modules used
Considered 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 3rd Intl Workshop on Page 4
Top Level Architecture of the FES GNC Page 5
FES models Spacecraft Propulsion Engine Management Attitude Control System Thrust Vector Control Aerodynamics Each stage modelled Page 6 Mass and Inertia Evolution Centring and Inertia Fuel Sloshing Mass Evolution
FES models Dynamics & Environment 6-dof Dynamics Translational Dynamics Rotational Dynamics Mars Gravity Model Simple 3rd order Complex n th order gravitational harmonics based on JPL50c Page 7 Mars atmosphere Model Look-up tables from EMCD 3.1 EMCD 3.1 interface directly embedded in FES
FES models Sensors Inertial Measurement Unit 3-axis accelerometer 3-axis gyrometer Alignment Matrix Page 8
FES generic models management Ascent profile induces required dedicated management Page 9
FES 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 Page 10 C-coded S-functions
GNC sequencing example 1 st Boost 2 nd Boost Coasting phase 3 rd Boost Coasting phase 1st Stage 2nd Stage Navigation Guidance TVC control Roll control Attitude control Page 11
ASCENTIS usage Page 12 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
FES use example: Guidance trade-off Algorithms comparison through performance index Guidance scheme Implicit Predictor-corrector Explicit 20 m/s requirement 18.5% 86.2% 98.8% 95% value 48.2 m/s 66.7 m/s 1.7 m/s Page 13
ASCENTIS plots Default plots run from single script Script manages plotting functions, additional plotting can be added if desired Page 14
ASCENTIS plots: Monte-Carlo (1/2) + Guidance X Navigation Page 15 Orbital elements @ injection
ASCENTIS plots: Monte-Carlo (2/2) Deflection envelope Q.α envelope Page 16
Conclusion 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 Page 17 Useful platform to assess performances for a Planetary ascent phase