importance of optimisation in space missions yabar.pdfesa unclassified – for official use...

ESA UNCLASSIFIED – For Official Use

Importance of Optimisation in Space Missions

Celia Yabar [email protected] 3rd OSE Workshop 17/09/2015

Importance of Optimisation in Space Missions | Celia Yabar | 17/09/2015 | Slide 2


Outline

1. ESA and its missions

2. Optimisation in space missions

3. Current optimisation challenges

4. Optimisation tools and techniques developed in the GNC section at ESA

5. Summary & Conclusions


ESA and its missions



About ESA and its programs

“ The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world ”

ESA is an international organization with 22 Member States

ESA activities:

• Observing the Earth • Human Spaceflight • Launchers • Navigation • Space Science

• Space Engineering • Operations • Technology • Telecommunications



Past ESA missions



Current and future ESA missions



Guidance Navigation and Control at ESA

• TEC-ECN Section (GNC Section)

• Where are we inside ESA?

• Directorate of Technical & Quality Management

– Electrical Engineering Department

– Control Systems division

– Guidance Navigation and Control section

• What do we do?

• Support ESA projects in the areas of GNC

• Manage and technical monitoring of R&D contracts

• Support to Concurrent Design Facility studies as GNC experts


Optimisation in space missions



Importance of Optimisation in Space

• Optimality is essential due to the exponential nature of the launcher propellant requirements with respect to payload mass and achievable destination

• Consideration of key mission objectives together with other crucial aspects such as technical feasibility, cost-efficiency and mission safety

• Space missions require the analysis and optimisation of trajectories, fuel consumption, cargo handling, subsystems design and many others

• Space missions are continuously becoming more complex requiring the solution of increasingly hard optimisation problems



Optimisation areas

Many areas where optimisation is interesting:

1. Mission analysis and trajectory planning

2. Planning and scheduling

3. Cargo loading and unloading

4. Payload accommodation

5. System design

6. Subsystem design

7. Ergonomic aspects

8. Payload performance

9. Observation data handling and remote monitoring

10.Cost and revenue management



Example Optimisation Areas (1/2)

Mission analysis and trajectory planning

• Reduce overall mission expenses and improve mission effectiveness

• Minimize propellant to enhance launch vehicle capabilities

• Minimize time, especially for future manned interplanetary missions

Planning and scheduling

• Minimize risks and cost of the mission

• ISS – permanent logistic support and on-orbit resources supply

• Quick re-scheduling when off-nominal scenarios



Example Optimisation Areas (2/2)

Cargo loading and unloading

• Optimize loading space and packing, object geometries

• Cargo accommodation inside ATV: mass and volume limitations, positioning rules, balancing conditions

System design

• The subsystem-specific optimisation objectives may be in conflict when considered jointly. Need to find an overall (globally) satisfactory solution.

• Multidisciplinary and multi-objective optimisation

Subsystem design

• Optimisation problems associated to a systems design

• structural, thermal, avionic, power, navigation, control,…


Optimisation challenges in current missions



Science mission: JUICE

Jupiter Icy moons Explorer (JUICE):

Europe’s first mission to the Jupiter system. It will make detailed observations of Jupiter and 3 of its largest moons, Ganymede, Calisto and Europa

Problem: Optimisation of the interplanetary trajectory to visit all Jupiter Moons in a minimum time with minimum fuel and maximum payload.

Difficult problem mostly because of many local minimums

Current solution: local optimisation by segments

Optimal Solution: Global optimisation techniques



Science mission: CHEOPS

CHaracterising ExOPlanet Satellite (CHEOPS)

Dedicated to searching for exoplanetary transits by performing ultra-high precision photometry on bright stars already known to host planets

Problem: ultra-high precision photometry requires ultra-high pointing accuracy

Current solution: Classical control (PIDs)

Optimal Solution: Robust optimal control



NEO space mission: AIDA (DART + AIM)

Double Asteroid Redirection Test (DART-NASA):

Modify the trajectory of the secondary asteroid of the Didymos binary system

Asteroid Impact Mission (AIM)

Rendezvous and characterisation of the asteroid system

Problem: Map the complete binary system before the impact using a high resolution camera minimizing the time and fuel consumption

Optimal Solution: Global optimisation for optimal mapping



Exploration missions: PHOOTPRINT

European Phobos Sample return mission (PHOOTPRINT)

Sample return of the moon of Mars Phobos. Science characterisation, landing, sample acquisition and return to the Earth with a re-entry capsule

Problem: Enable autonomous flight that can automatically recover from unexpected problems: failures, abort scenarios, landing site change,…

Current Solution: Ground in the loop Navigation and trajectory planning

Optimal Solution: Real-time trajectory optimisation



Launchers (1)

Design of a new launch vehicle

Problem: The design of a new launch vehicles is a very complex task. Need of an optimized configuration that yields sufficient payload performance at minimum cost

Current solution: iterative process during which experts from various disciplines refine and update their subsystem designs until they converge to a consistent, good design

Optimal solution: tackle the problem as a multi-disciplinary design optimisation (MDO) and avoid decomposing the system



Launchers (2)

VEGA launcher roll control

Problem: The presence of roll during the first stage of the VEGA Launcher vehicle, which needs to be controlled.

The causes of roll are:

- Roll torque induced by geometrical imperfections

- Roll torque induced by the combustion

- Aerodynamics and winds

Current solution: classical control design + extensive validation campaign

Optimal solution: use of H-infinity optimized methods to reduce development cost and guarantee robustness “by design”



Launchers (3)

V&V analysis to guarantee the mission’s safety

The stability and performance must be assessed for nominal as well as including uncertainty in mission parameters

Problem: determine the combination of uncertain parameters that leads to the worst case performance violation

Current solution: Traditional Monte Carlo campaigns (randomly sampling the uncertain parameters according to statistical distributions)

Optimal solution: Identify the uncertain parameter combination which provides extremum values of a given performance criterion by employing different local, global and hybrid optimisation methods.



GALILEO constellation

GALILEO constellation

Europe’s own global satellite navigation system

30 satellites in MEO (10 satellites /orbital plane, 56° inclination)

Problem: Need for an efficient satellite constellation management plan including strategies for launch, set-up and replacement

Optimal solution: global optimisation to define the best deployment strategy minimizing cost and time



Telecommunications: ELECTRA Program

Electra Program:

A full electric-propulsion telecommunications satellite in the 3-tonne launch mass range

Problem: replacing the apogee kick-engine by Electric Propulsion for transfer from injection orbit to GEO requires an optimized low thrust trajectory

Optimal solution: high-fidelity optimisation of electric propulsion orbit raising manoeuvres


Optimisation tools and techniques developed by the

TEC-ECN section



Optimisation tools and techniques (1)

WORHP: We optimize really huge problems

• European Mathematical NLP Solver. Tool for solving large-scale, sparse, nonlinear optimisation problems with millions of variables and constraints (Uni Bremen, Uni Southampton, Uni Coimbra, Astos Solutions)

• Extension of WORHP to multi- and many-core Architectures (Steinbeis Forschungszentrum)

• Enhancement of WORHP using Parametric Sensitivity Analysis with respect to Hessian regularization and constraint relaxation (2015,TBC)

MIDACO solver: Mixed Integer Distributed Ant Colony Optimisation (Airbus)

• Solver for general optimisation problems that can be applied to continuous (NLP), discrete/integer (IP) and mixed integer (MINLP) problems




Global optimisation

• Assessment of global optimisation mathematical methods for space engineering (University of Southampton)

Filtering techniques (University of Southampton, Coimbra and Birmingham)

• Versatility of Filtering Techniques in Non-Linear Programming Optimisation

• FGS: Filtering and globalization strategies toolbox

• MCO (Multiple Cost Optimisation) Add-On for the FGS Toolbox Filtering

• Uses the same concept of multiple filters to have multiple objectives (costs)




Trajectory optimisation

• ASTOS Frame Contract (upgrade and update of optimisation capabilities)

• AeroSpace Trajectory Optimisation Software (Astos Solutions)

• Development of the Hybrid Transcription Method CAMTOS (Astos Solutions)

• Hybrid optimizer which allows the choice of collocation and multiple shooting at each phase

• Development of PROMIS / TROPIC (DLR)

• Trajectory optimization using direct collocation (TROPIC)

• Parameterized trajectory optimization by direct multiple shooting (PROMIS)




• Optimisation of NS/EW Station-Keeping Manoeuvres for GEO Satellites using Electric

Propulsion (GMV & Airbus)

• Multi-Disciplinary Optimisation for Launchers and Reentry Vehicles (ASTOS, RUAG)

• Electric Propulsion Orbit Raising Analysis and Optimisation Tool (ASTOS & GMV)

• Worse case Analysis Tool WCAT (University of Exeter)

• LPV modeling analysis and design (LPVMAD, Deimos Space)

PhDs

• Prestige Program: Multi-disciplinary design optimisation for space vehicles (Bremen

University, Politecnico di Milano)

• NPI Program: Multi-objective hybrid optimal control problems (Strathclyde University

& Airbus, on-going)



Possible collaborations

Technology research and development programs

Information

TRP: Basic Technology Research Programme

Part of ESA’s mandatory Basic Activities The backbone of ESA’s innovation effort covering up to proof-of-concept TRL 3 50 M€ in industrial contracts per Year, 150 contracts per year

GSTP: General Support Technology Programme

Covering all technology disciplines and applications except Telecommunications (covered by the ARTES programmes) Ensures that the right technology with the right maturity are available at the right time 45-60 M€ in industrial contracts per Year, 60-80 activities

NPI: Network/Partnering Initiative

Innovative doctoral or post-doctoral proposals with the collaboration of research institutes, universities and industry

ITI: Innovation Triangle Initiative

Requires the collaboration of 3 different entities: Inventor, developer and customer Part of TRP budget (4 M€)

Assessment TEC-ECN ECN Engineering Support Tools and Assessment activities



Summary and Conclusions

• Optimisation is indispensable in many different aspects of any

space mission

• Space missions are continuously becoming more complex requiring

the solution of increasingly hard optimisation problems

• Collaboration between ESA, industry and academia is essential to

continue innovating regarding both theoretical advances and

ready-to-use tools for actual applications



Thank you!

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