CDF Astrodynamics CDF Presentation - 1
Astrodynamics tools in the ESTEC Concurrent
Design Facility
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Robin BiesbroekCDF Technical Assistant
ESA/ESTECNoordwijk - NL
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Introduction• ‘Concurrent Design Facility’ (CDF):
– ESA Mission Analysis, Conceptual design, pre-assessment studies & Industry reviews.
– Apply methods and tools of concurrent engineering– Integrated Design Model (Excel → Oracle)
• Strong focus on:– ‘Real-time’ results i.e. during design sessions– Connectivity: linking to other tools, and Excel– Variety: applications range from LEO to deep-space
• CDF is a facility– We offer our users a set of astrodynamics tools– The user is free to use these or not– But: results imported into Excel to share with others
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Overview of tools in the CDF• Developed especially for the CDF:
– Swing-by Calculator (JAQAR Astrodynamics package)
• Commercially Off The Shelf:– Microsoft Excel– AGI’s Satellite Tool Kit (STK)
• ESA developments– IMAT and ORION (GMV)– ASTOS (IFR)– MASTER (eta_max, aerospace systems, QinetiQ)
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JAQAR Astrodynamics package• Consists of 6 software tools:
– Swing-by Calculator (SBC)– Orbit Transfer Optimiser– Tetsim tether simulator– Orbit-parameters calculator– STKephem– LTO (Lunar Transfer Orbit) calculator
• Extra package for CDF:– Events: coverage visualisation
• SBC & Events originally developed for the CDF– LTO calculator for WSB transfers of LunarSat
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Swing-by Calculator• PC-based (Windows XP)• Optimisation of
interplanetary transfers– Maximum 5 swing-bys– Deep-space manoeuvres– Low-thrust– Aero-gravity assists– Resonance orbits– Launch windows
• 3 optimisers:– Genetic Algorithm– Systematic search– Monte-Carlo
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Swing-by Calculator (2)• User-defined ephemeris (comets, asteroids)• Orbit visualisation• Launcher data-base• Trajectory files
– Excel format– STK format– IMAT format
• Creates entire STK scenario – numerical propagation– G/S coverage– Eclipse times
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SBC Genetic Algorithm• A contract was awarded by ESOC in 2003 to
investigate genetic algorithm settings– Mission to Pluto (via Venus & Mars)– Cassini-Huygens– Mission to Europa (Jovian Moon swing-bys)
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SBC low thrust optimisation• Low thrust parameters
are the same as impulsive Deep-space manoeuvre– B-plane parameters of
previous swing-by– Start-time– SBC determines end-
time– Only finite thrust is
propagated
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Orbit Transfer Optimiser• PC-based (Windows XP)• Systematic search of 1/2/3
impulse transfer– Plane change– Node change– Pericenter change– Hyperbolic entry/exit
• Any planet• Creates STK scenario
– numerical propagation– G/S coverage– Eclipse times– Link to STK is done via HTML
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LTO Calculator• Currently optimisation of
Weak-Stability Boundary (WSB) transfers
• Upgraded:– Direct transfers– Bi-elliptic– STK interface
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Events & STKephem• Events:
– Creates daily event-patterns (G/S visibility, eclipse) from IMAT results
• 1 satellite to multiple G/S• Multiple satellites to 1 G/S
– Result is bitmap & Excel output
• Portable to CDF final report & Excel
• STKephem– Converts any trajectory file to STK format– Freeware
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Availability of JAQAR software• JAQAR Astrodynamics Package can be
downloaded from the internet– www.jaqar.com
• Users of the Swing-by Calculator:– ESA– SSTL (Surrey Satellite Technology Ltd.)– NASA Goddard spaceflight centre– Other companies (demo-version)– >100 students all over the
world (student version)
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Use of Excel for mission analysis
• A dedicated mission analysis Excel workbook has been developed– Links inputs & outputs to other sub-systems– Used for calculations, storage & presentations– Contains >50 macros for calculations
• Launcher performance, Sun-synchronous orbits, repeating ground-track orbits, ∆V & propellant
– Data-base sheets– Import trajectory files from IMAT, SBC, STK
and ASTOS
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Excel ExampleTable of altitudes
Macro givesperformance
Macro gives dry mass in hyperbolic orbit
Visualisation to findoptimum apogee
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STK in the CDF• Used for:
– orbit transfer– 3D representation
• Understanding for the team
• Verification of orbit• Movies
– G/S coverage– Eclipse times– GNC/AOCS– Parameter evaluation
• User-defined
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CDF connectivitySTK
Excel
SBC
OTO
HTML
The future?
CDFESOC
HTML interface
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IMATInstrument Mission Analysis Tool
• Evaluate instrument return for planetary surface coverage
• Quick Assessment– Orbit propagation– Gravity loss/burn duration
• Auxiliary Calculations– Eclipse times– Ground-station visibility
• Planetary orbits only• Developed by GMV, Spain
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ORIONOrbit Constellation Tool
• Constellation requirements and design• Analysis of constellation performance• Launch strategy and constellation set-up• Launcher Database
– Corresponds to the CDF database in Excel
• Constellation orbit determination and maintenance
• Constellation replacement and end-of-life strategy
• Developed by GMV, Spain
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ASTOSAerospace Trajectory optimisation Software
• Used in preparation of & during projects• Application to future launchers
(Ariane 5 ECA/ECB)• Optimisation of multi-phase
problems based on PROMIS or TROPIC
• Applicable to atmospheric re-entry and aero-capture
• Creates STK trajectory/attitude file
• Developed by IFR (Stuttgart), Germany• www.astos.de
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MASTER• Meteoroid and Space Debris Terrestrial
Environment Reference Model• Characterization of the natural and the man-made
particulate environment of the Earth– Fast and simple evaluation of the resulting effects on
space missions.– semi-deterministic analysis of a reference population
derived from the simulation of all major space debris source terms.
– Used to assess risk of debris impact– Developed by eta_max, aerospace systems, QinetiQ
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Conclusions
• CDF as a facility offers its users a set of Astrodynamics tools covering a wide field of applications– Personal preference of users to use this set or not
• Strong focus on connectivity– Future trend → more and more important
• Successful results from mission analysis in all CDF studies– Despite the ‘fast track’ constraints