ASTRIUM - Index of

Generic all purpose ASTRIUM Space 

Transportation reference trajectory 

optimization tools 

ASTRIUM 

Nathalie DELATTRE, Mission Analysis Team 

Summary 

Introduction 

Presentation of the generic tool 

A validated tool 

Various examples 

Conclusions 

Page 1 

Ce document et les informations qu'il contient sont propriété d'Astrium. Il ne doit pas être utilisé à d'autres fins que celles pour lesquelles il a été remis. Il ne peut être ni 

reproduit, ni divulgué à des tiers (en tout ou partie) sans l'accord préalable et écrit d'Astrium. Astrium SAS – Tous droits réservés. // This document and the information it 

contains are property of Astrium. It shall not be used for any purpose other than those for which it was supplied. It shall not be reproduced or disclosed (in whole or in part) to 

any third party without Astrium prior written consent. Astrium SAS – All rights reserved.


Introduction 

Page 2 





Where Mission Analysis is acting 

Configuration DOF 


Concept 

definition 

system loops 

Preliminary design 

high level 

recommandations 

Sub-systems 

specification 

contribution 

Flight strategy 

design 

Flight strategy 

tuning 

Reference 

Trajectory 

Performance and budget assessment 

PHASE 0 PHASE A PHASE A/B PHASE B/C/D PHASE C/D ALL PHASES 

Development Phase 

Page 3 





Mission Analysis 

Location in the system loop 

Ref. trajectory 

Constraints 

Specifications 

Data 

Software customisation 


Transitory 

flight 

phases 

Guidance 

Thermal 

studies 

Navigation 

Structural 

&Mechanical 

studies 

Mission Analysis 

« Stage » 

design 

Control 

Aerodynamics 

Avionics 

Propulsion 

Cost 

Page 4 

SIZING 

FLIGHT CONTROL 






Presentation of the generic tool 

Page 5 





Generic trajectory optimization tool 


• MAXTOM/OSCAR : brief description 

Ascent and reentry trajectory 

Optimisable design parameters (sizing, propulsion 

parameters or laws) 

Possibility of two branches 

Representative 3 DOF trajectory integration 

High number of constraints and criteria available and user’s 

defined parameters 

Library of gravity and atmosphere models 

Possibility of plug-ins models such as propulsion laws, 

design parameters, guidance model 

Parametric optimizer 

Page 6 






A validated tool 

Page 7 





Performance evaluation for Ariane 5 or 

ballistic missile 


Inputs for Ariane 5 

Detailed definition of the different 

stages (propulsion laws, mass, 

drag coefficients …) 

Detailed constraints such as the 

chosen orbit, dynamic pressure, 

visibility constraints 

Outputs 

Detailed trajectory 

Injected mass 

Inputs for ballistic missile 

Detailed definition of the 

different stages (propulsion 

laws, structural mass, drag 

coefficients …) 

Constraints such dynamic 

pressure, 

Outputs 

Detailed trajectory 

Downrange 

Page 8 





Launch vehicle : trajectory overview 


• Find the optimum trajectory compliant with the 

mission and design constraints 

Orbit injection 

- position 

- velocity 

Fairing jettison 

(thermal flux) 

Thermal flux 

Stage separations 

(dynamic pressure) 

120km 

Stage fall-out 

Atmospheric phase 

- loads 

- control 

Launch pad 

visibility 

fragmentation 

station 1 station 2 

Close safety 

Far safety 

Debris impact zone 

Page 9 






80 

60 

40 

20 

latitude (deg) 

0 

-20 

impact EPC 

injection 

-40 

-60 

-80 

-240 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 

longitude (deg) 

Page 10 






Constraints concerning the fall-out 

of the EPC 

Angle of attack during the reentry 

20 

15 

Relative velocity during the reentry 

Ground tracking 


10 

5 

0 

debris arriere 

EPC incidence nulle 

debris avant 

Position of the aft and fore debris 

-5 

Impact zone 

-10 

-100 -80 


Page 11 






50000 

PRESSION DYNAMIQUE 

40 

ACCELERATION LONGITUDINALE 

40000 

41064 Pa 

35 

30 

Pdyn (Pa) 

30000 

20000 

10000 

Acc longi (m/s2) 

25 

20 

15 

10 

5 

0 

0 20 40 60 80 100 120 140 160 

Temps / H0 (sec) 

0 

0 500 1000 1500 2000 


FLUX THERMIQUE 

800 

FLUX THERMIQUE 

Flux (W/m2) 

1800 

1600 

1400 

1200 

largage coiffe 

1000 

800 

600 

210 215 220 225 230 


Flux (W/m2) 

700 

second pic de flux 

600 

500 

400 

300 

200 

100 

0 

450 460 470 480 490 500 510 520 530 540 550 


flux thermique altitude 

Page 12 






30 

20 

10 


0 

-10 

Kourou 

Natal 

Ascension 

Malindi 

injection 

-20 

-30 

FENETRA 

-60 -40 -20 0 20 40 60 


Ce document est la propriété d’EADS LAUNCH VEHICLES. Il ne peut être communiqué à des tiers et/ou reproduit sans son autorisation écrite. 

Son contenu ne peut être divulgué.© - EADS LAUNCH VEHICLES - 2002 

Page 13 






55 

50 

45 

40 

35 

Elevation (deg) 

30 

25 

20 

15 

10 

5 

-0.24 deg 

2.1 deg 

0.22 deg 

0 

FENETRA 

0 200 400 600 800 1000 1200 1400 1600 


Kourou Natal Ascension Malindi 

Ce document est la propriété d’EADS LAUNCH VEHICLES. Il ne peut être communiqué à des tiers et/ou reproduit sans son autorisation écrite. 

Son contenu ne peut être divulgué.© - EADS LAUNCH VEHICLES - 2002 

Page 14 





Flight proven tool 


• MAXTOM/OSCAR 

Validation through its use on the launch systems, in 

comparison with the flight 

Restitution of launcher performance 

Flight proven results : Ariane 5, french ballistic missiles, 

ARD (atmospheric reentry demonstrator) 

Page 15 






Various examples 

Page 16 





Large usefulness of the in-house tool 


• Large use for all the projects in Astrium 

Advanced-projects such future expendable launchers, 

reusable launchers 

Many design studies 

Mission 

Payload 

Spacecraft To be defined Exists 

Objectives to be realized 

(specifications) 

Inputs 

To be evaluated 

Inputs 

Input 

Type of problem Preliminaries studies Global performances Flight preparation 

Phase 

Staging optimisation 

Optimized trajectories 

Differents options 

Optimized trajectories 

Maximum payload per 

mission 

Outputs Definition manuel d’utilisateur 

(comparaison avec 

d’autres lanceurs) 

Flight trajectory 

(constraint) 

command law 

(flight software) 

Flight software 

Flight prevision 

(nominal and with 

dispersions) 

Page 17 





Advanced projects – future launch 

vehicles 

Expendable launch vehicles 

– Purpose : propose a launcher configuration compliant with 

technological constraints (engines, propellants, structural index) 

– Process to be followed: 


1) analytical staging 

2) Preliminary verification using a simplified trajectory optimization 

tool 

3) Reference trajectory with all mission constraints ( fall-down , 

tracking, loads) 

– Output : Configuration proposed 

Page 18 





Advanced projects – future launch 

vehicles 

Reusable launch vehicles 

– Same problem and solving process 

– More complex configuration definition (aerodynamic, 

atmospheric flight, angle of attack different from 0) 


Page 19 

– Additional recovery 

constraints 

– Example for a TSTO : 

Search of an optimization 

between the two stages. 

for both the Booster 

return to the launch site, 

including a cruise flight, 

and the Orbiter reentry, 

including the deorbitation 

maneuver 

Booster + Orbiter 

propelled 

1 

Kourou 

Booster 

ballistic 

Booster 

Air-breathed propelled 

Orbiter 

propelled 

~ 5-10 km 




any third party without Astrium prior written consent. Astrium SAS – All rights reserved. 

3 

2 

Booster 

gliding 

Ground 

LEO 

200 km

RLV 

Ascent Trajectory Analysis 

Trajectory problem statement 


T 

thrust 

Find at every date the optimal values of 

• α(t) : angle of attack 

• β(t) : thrust deflection 

from lift-off to injection 

F A 

aerodynamic force 

G 

W 

weight 

β 

α 

X L 

launcher axis 

V r 

Constraints 

• controllability : control of the total torque applied 

• path constraints : mechanical and thermal loads along the ascent 

path 

• injection orbit : LEO 200-km circular 

7-deg inclined 

Page 20 





RLV 

Ascent Trajectory Analysis 


Control problem statement 

• Find at every date the thrust deflection value β trimming the 

aerodynamic torque M aero 

M Thrust + M Aero = 0 

→ static deflection β = β s (α) 

Static control 

Trimming condition : β(t) < β max 

α(t) 

M Aero 

+M Thrust 

=0 

β s 

(t) 

F A 

T 

CoG motion 

Page 21 





Advanced projects 

Aerocapture demonstrator 


ATPE program : terrestrial aerocapture demonstration 

(Launch by Soyuz) 

 

Injection of a demonstrator in order to get interplanetary 

arrival conditions at the atmospheric entry (velocity) 

Page 22 






Page 23 

The generic tools enable to propose a scenario and to perform the 

convenient end-to-end trajectory. 






Conclusions 

Page 24 





Conclusions 


As prime of the Ariane family – and also as prime for ballistic 

missiles - , ASTRIUM ST has more than 20 years of experience 

in launch mission analysis. 

• In-house generic tools are flight proven through family Ariane, 

french ballistic missile, ARD. 

• The generic mission analysis tools has been used intensively 

in various developments : ATV, ARD, CRV, CTV, MSR, pre-X, 

IXV ATPE, MAV, EVEREST TSTO, ExoMars, … 

• Capacity of end-to-end scenario, and branched scenario 

• One generic software tool for all ELV/RLV/reentry vehicles 

mission analysis 

• Modelling synergy which benefits to all the mission analyses 

performed, through phases 0, A, B. 

Page 25

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