This thesis is on the subject of how propellant heating considerations affect the design of a CubeSat cold gas propulsion system. Computer simulation tools are used to analyse heat flow through the system, as well as the fluid flow and phase change of butane. The heating performance is presented for different operational states and different designs. Finally, an optimal system design is suggested. The propulsion system in question is the deep space heading Hera Juventas 6DOF CGPS. The Juventas spacecraft will as part of ESA’s Hera mission be the first to perform radar measurements of an asteroid. It will determine the result of the NASA DART mission and will give insights to the internal structure of the Dimorphos minor- planet moon. / Detta examensarbete behandlar utformningen av ett CubeSat kallgasframdrivningssystem med avseende på drivmedelsuppvärmning. Datorsimuleringsverktyg används för att analysera värmeflöde genom systemet samt flödet och fasförändringen av butan. Värmningsprestanda presenteras för olika driftstillstånd och olika konstruktioner. Slutligen föreslås en optimal systemdesign. Framdrivningssystemet i fråga är Hera Juventas 6DOF CGPS. Rymdfarkosten Juventas kommer som en del av ESA:s Herauppdrag att vara den första som utför radarmätningar av en asteroid. Den kommer att avgöra resultatet av NASA:s DARTuppdrag och kommer att ge insikter om den interna strukturen i asteroidmånen Dimorphos.

Since mankind found out that she is the reason to the recent global warming shehas, in some societies, begun a conversion of her society, from driven by fossil fuel tosustainable fuel. One of these is so called wave energy.CorPower Ocean's wave energy converter consist of a buoy, which through a wire,is connected to a shaft in the plant. This shaft drives two gas lled and pressurisedpistons, which stores the energy from the buoy's upward motion and returns it at thebuoy downward motion, aiming at evening the energy production over the cycle. Inthe wave energy converter there are several seals, between hydraulic uids, betweenhydraulic uids and the gas pistons as well as between the plant and the surroundingocean where the shaft exits the plant.To select the right kind of seals the range in the working temperature of the surroundinguids need to be known, as do the load of the waves on the shaft. This inorder to select seals of the right material and to construct a linear guide.The purpose of this thesis is to acquire the initial demands for the seal and linearguide. In other words make a thermal analysis of the surrounding environmentin order to select seals and an initial load analysis in order to construct a robustlinear guide.The result is that in order to control the temperature, a reservoir volume shouldbe added to the cylinders and a change in this volume gives the most eect on thetemperature and compression rate. Regarding the linear guides, slide rings on bothsides of the two outer seals should be enough. This thesis should be viewed as aninitial analysis of the sealing problem to be able to outline the demands on the sealsand linear guides related to the gas compartments. / Sedan manninskan ck reda pa att hon ar orsaken till den senaste tidens globalauppvarming har hon, i nagra samhallen, paborjat en omstallning av sitt samhalle,fran fossila branslen som drivmedel till langsiktigt hallbara drivmedel. Ett av dessaar sa kallad vagkraft.CorPower Oceans vagkraftverk bestar av en boj, som genom en vajer faster i endragstang i sjalva kraftverket. Denna dragstang driver tva gasfyllda och trycksattakolvar, som lagrar energin fran bojens uppgaende rorelse och aterger den vid bojensnedgande rorelse, med malet att dessa jamnar ut kraftproduktionen over cykeln. Iverket nns era tatningar, mellan olika hydraulvatskor, mellan hydraulvatskor ochgaskamrarna samt mellan verket och det omgivande havet dar dragstangen gar ut urverket.For att kunna valja ratt tatningar maste spannet i arbetstemperatur pa de omgivandeuiderna, samt lasten fran vagorna pa dragstangen, vara kanda. Detta foratt tatningar av ratt material ska kunna valjas och en linjarguide konstrueras.Detta arbete syftar till att ta fram de initiella kraven pa tating och linjarguide.Med andra ord gora en termisk analys av den omgivande miljon for att kunnavalja tatningar samt en inledande kraftanalys for att kunna konstruera en robustlinjarguide.Slutsatsen blir att for att styra temperaturen, bor en reservoirvolym laggas till cylindrarnaoch en andring av volymen pa denna ger storst eekt pa gasens temperaturoch kompressionsgrad. For linjarguidens del bor det ga bra med glidringar pa badasidor om de yttersta tatningarna. Det exakta valet av tatingslosning kommer Cor-Power Ocean dock att arbeta fram med ett lampligt foretag. Denna uppsats ska sessom en inledande analys av tatningsproblemet for att kunna ange huvuddragen avkraven pa tatningar och linjarguider relaterade till gascylindrarna

This master thesis addresses the development of an automatic numerical tool for thermal analysis, focusing on thermal systems comprising a printed circuit board assembly and cooling case structure. The project, conducted in collaboration with Unibap, aims to enhance the design process of space computer modules by automating middle steps between design software and thermal analysis results. The numerical tool employs the lumped parameter method, implemented in Python, as an alternative to traditional finite element analysis to efficiently generate thermal results. Informed decisions can be made using the tool regarding case-cooling and the selection of components requiring cooling, thus optimizing manufacturing costs and design complexity. The project results in the successful development of the automatic numerical tool. A unique method to derive values for thermal resistance within the case structure is also utilized. Though experimental test results for verification are pending, the functionality of the tool is presented along with results from a thermal analysis where it is used.