Table Of ContentPreliminary Trajectory Design of a Mission to Enceladus
David Falcato Fialho Palma
Thesis to obtain the Master of Science Degree in
Aerospace Engineering
Supervisor(s): Prof. Paulo Jorge Soares Gil
Eng. Nuno Tiago Salavessa Cardoso Hormigo Vicente
Examination Committee
Chairperson: Professor João Manuel Lage de Miranda Lemos
Supervisor: Prof. Paulo Jorge Soares Gil
Member of the Committee: Prof. João Manuel Gonçalves de Sousa Oliveira
December 2016
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“SoLong,andThanksforAlltheFish”
—DouglasAdams
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Acknowledgments
I would like to start by expressing my gratitude to my supervisor, Prof. Paulo Gil, who taught me many
valuable things, technical and beyond, but above all for his relentless support, encouragement and
experience which helped shape this work. I also extend my best regards to Spin.Works, especially my
co-supervisor Engineer Tiago Hormigo and Engineer Joa˜o Seabra, for the interesting challenge that
wasproposedandfortheirguidanceintheprocess.
Secondly,I’dliketoacknowledgemyfriends,especiallymybrothersinarms—NunoMartins,Jorge
Arau´jo and Daniel Gonc¸alves — whose support, encouragement, fellowship and company for the long
nightshavebeenindispensabletomysuccessinthisworkandprogramme.
To Mo´nica, at the Mechanical Engineering bar, a big thank you for brightening up so many days of
hardworkwithacoffeeandasmile!
I am also deeply grateful to my best friend, Catarina Farinha, for her wisdom and never-ending
supportandpatience.
Finally,Iwouldliketoextendaspecialwordtomyfamily,tothosewhoarewithusandtothosewho
arenot,whohavebeentheinstrumentsthatguidedmeallthewayhere.
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Resumo
Asageˆnciasespaciaisdespertaramrecentementeparaaimportaˆnciadaexplorac¸a˜odemundosoceaˆnicos.
Alguns destes corpos celestes, como Enceladus e Europa, orbitam dentro dos sistemas lunares de
planetas gigantes, como Jupiter e Saturno. A vontade de investigar estas luas em detalhe motivou a
concepc¸a˜odeumanovaclassedetrajecto´rias—complexos“moontours”queteˆmcomoobjectivouma
reduc¸a˜o dra´stica do custo de inserc¸a˜o orbital naquelas luas. Este trabalho ataca o desafio espec´ıfico
de desenvolver uma trajecto´ria preliminar que possibilite o envio de uma sonda, com a maior massa
poss´ıvel, para o´rbita de Enceladus. Para comec¸ar, a estrutura da missa˜o e´ definida. De seguida,
o ca´lculo da trajecto´ria comec¸a com a optimizac¸a˜o de diversas sequeˆncias interplaneta´rias, obtidas
atrave´s de um processo baseado em diagramas de Tisserand. Para permitir isto, um processo de
optimizac¸a˜oglobalqueenvolvecooperac¸a˜oentrealgoritmosestoca´sticose´ delineadoeimplementado.
Paraobtersoluc¸o˜esparao“moontour”,umate´cnicamodernadenomeadaV -Leveraging e´ estudada
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eusada,demonstrandoseressencialnestetipodemisso˜es. Finalmente,numpassoale´mdaliteratura
actual, o efeito da inclusa˜o de transfereˆncias inter-lua na soluc¸a˜o do “moon tour” e´ discutido e consid-
erado na˜o negligencia´vel. O resultado deste trabalho e´ um exemplo de uma trajecto´ria preliminar que
permite a colocac¸a˜o de um sate´lite com, no ma´ximo, 2 toneladas, em o´rbita de Enceladus num prazo
de13.9anos.
Palavras-chave:
Enceladus, circuito inter-luas, alavancamento de V , optimizac¸a˜o de tra-
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jecto´rias,mundosoceaˆnicos,diagramasdeTisserand
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Abstract
Space agencies have recently awoken to the importance of exploring ocean worlds. Some of these
celestialbodies,suchasEnceladusandEuropa,existwithinthedynamicmoonsystemsofgiantplanets
like Jupiter and Saturn. The will to investigate these moons in detail motivated the study of a new
class of trajectories — complex moon tours with the objective of drastically cutting down on the cost
of orbital capture at these moons. This work tackles the specific challenge of designing a preliminary
spacecraft trajectory capable of delivering as much mass as possible to Enceladus’ orbit. To begin
with,aframeworkforthemissionisestablished. Then,thetrajectorydesignstartswiththeoptimisation
of several interplanetary flight sequences, obtained through a process based on Tisserand plots. To
achieve this, a global optimisation procedure with a cooperative stochastic topology is outlined and
implemented. Toobtainsolutionsforthemoontour,amodernV -Leveragingtechnique,demonstrated
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tobeessentialforthisclassofmissions,isstudiedandused. Finally,inastepbeyondcurrentliterature,
theeffectoftheadditionofinter-moontransferorbitstothemoontour’ssolutionisdiscussedandfound
to be non-negligible. The outcome of this work is an example preliminary trajectory that enables an
Enceladusorbiterspacecraftofuptotwotonnes,withinamissiontimeof13.9years.
Keywords:
Enceladus,moon tour, V -Leveraging, trajectory optimisation, ocean worlds, Tis-
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serandplot
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Description:To Mónica, at the Mechanical Engineering bar, a big thank you for spacecraft trajectory capable of delivering as much mass as possible to discussed in the JUICE's Consolidated Report on Mission Analysis (CReMA) Load the entire DE kernel into local variables and access it safely, passing it
