Master Thesis - OUFTI-1

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Components Mass (g) Box 27.33 Cover 19.24 4 screws M3 × 8 mm 4 × 0.465 = 1.86 4 spacers 4 mm 4 × 0.0775 = 0.31 4 spacers 19 mm 4 × 0.3575 = 1.43 2 batteries KOKAM SLB 603870H 2 × 33 = 66 4 wires 4 × 2 = 8 2 heaters 2 × 1.5 = 3 4 thermostats 4 × 0.2125 = 0.85 8 wires 8 × 1.25 = 10 Thermal insulator 0.08 Total 138.1 Table 3.6: Necessary mass budget This budget is well lower than the available mass budget, which is of 153.29 g. So, our design is valid with regard to the mass. 3.9.2 Static loads Then, the structural integrity of the support under static loads at which it will be submitted during the launch phase, must be veried. For this, some FE analysis have to be performed. To limit the modeling eorts, only the relevant structural parts will be considered. The modeling strategy for each part of the support is: • The box and the cover of the support are exible volumes made of Al − 7075 T 6. The properties of this material are: Young's modulus: E = 72.5 GP a Poisson ratio: ν = 0.33 Density: ρ = 2800 kg/m 3 • The batteries, which are also exible volumes, weight 32 g and have a volume of 1.482 × 10 −5 m 3 in nominal conditions, which lead to a density of 2159.25 kg/m 3 . However, their Young's modulus can not be estimated and is not provided in the datasheets. To determine it, some static bench tests would be necessary but, in our case, these components will be represented by increasing the density of the support inside the area normally occuped by the batteries. 65
• Other components, including thermostats, heaters and thermal insulator, are less important and do not aect signicantly the global dynamic behavior of the support. So, they will be ignored in this model. At this level, the precise acceleration at which the support is submitted, is not known (because a model of the entire satellite is not available). In addition, the boundary conditions can not be determined exactly. So, it was decided to follow a conservative approach using the following approximations: • The connections with the endless screws are supposed to be perfectly rigid in the 3 spatial directions. This approximation is pretty good because the spacers between the electronic cards and the support can be considered as extremely rigid in their longitudinal axis. In addition, the endless screws, which are xed at each of their extremities, can also be considered as rigid xations. However, for the rotational Degrees of Freedom (DoF), there is a certain exibility, due to the little set between the screws and the support's holes, that can not be measured accurately without having a complete engineering model of the satellite. So, these ones are let free, which lead to an overestimation of the structural deections and an underestimation of the natural frequencies. • The acceleration applied to the support is not known. However, a known value is the maximal acceleration of the launcher along its longitudinal axis, which is the more constraining one and rates 6.3 g. So, using a SF of 2, this acceleration reaches a value of 12.6 g that will be applied to our model. The results obtained are presented in Figure 3.24. It can be directly noted that the maximum Von Mises stress inside the support is situated, as predicted before, at the level of the legs. However, even with our approximations and the conservative approach applied here, the value of this stress (1.53 MP a) is strongly lower than the yield stress of the Al − 7075 T 6, which has a value of 444.5 MP a. 66
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University of Liège Faculty of App
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Abstract OUFTI-1, standing for "Orb
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3.4 Initial idea . . . . . . . . .
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List of Figures 1.1 The Pumpkin's C
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4.18 MAC matrix using the simple me
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List of Acronyms ADCS Al AlNiCo ASI
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Thesis outline This thesis focuses
Page 15 and 16: of larger satellites. So, the CubeS
Page 17 and 18: 1.2 OUFTI-1 project 1.2.1 Genesis O
Page 19 and 20: • XatCobeo (Vigo - Spain): Develo
Page 21 and 22: Chapter 2 OUFTI-1: Flight system co
Page 23 and 24: Figure 2.2: Product tree of OUFTI-1
Page 25 and 26: 2.3.2 Solar panels The armor panels
Page 27 and 28: • We do not want to drill or manu
Page 29 and 30: In our case, because of the limited
Page 31 and 32: Figure 2.13: Magnetic eld obtained
Page 33 and 34: Figure 2.17: Pictures of the ADCS c
Page 35 and 36: consider the possibility of oshorin
Page 37 and 38: Figure 2.20: Exploded view of OUFTI
Page 39 and 40: I xx , I yy and I zz are called the
Page 41 and 42: Subsystem: Structure & Conguration
Page 43 and 44: Subsystem: Thermal Control Parts Co
Page 45 and 46: Chapter 3 Design of a new support f
Page 47 and 48: Figure 3.3: Batteries during and af
Page 49 and 50: The concept is the following one: F
Page 51 and 52: A test under vacuum conditions was
Page 53 and 54: Thermal Expansion (CTE) of the mate
Page 55 and 56: Figure 3.9: Classication by density
Page 57 and 58: The last property to determine is t
Page 59 and 60: • So, it was decided to use two t
Page 61 and 62: is to prevent the batteries' bulge.
Page 63 and 64: • Then, the thermostats, that wil
Page 65: Figure 3.23: Schematics of the cove
Page 69 and 70: 3.9.3 Dynamic behavior Finally, it
Page 71 and 72: 3.10 Summary Through this chapter,
Page 73 and 74: Chapter 4 Electronic cards dynamic
Page 75 and 76: Figure 4.1: Example of manufacturin
Page 77 and 78: Figure 4.4: Illustration of the exp
Page 79 and 80: Figure 4.5: MAC between the two mod
Page 81 and 82: • Global mass/stiness smearing me
Page 83 and 84: 4.2.6 Modeling of the chassis A gen
Page 85 and 86: Q = ω k = 1 ω b − ω a 2 ζ ⇒
Page 87 and 88: Their study was based on the fact t
Page 89 and 90: Figure 4.14: Example of spacecraft
Page 91 and 92: Figure 4.15: Location of measuremen
Page 93 and 94: Figure 4.18: MAC matrix using the s
Page 95 and 96: 4.3.6 Application of the local mass
Page 97 and 98: ρ P C 104 connector = 10.12 × 10
Page 99 and 100: According to this particular shape,
Page 101 and 102: This is due to the fact that this c
Page 103 and 104: environment. Then, this model is ex
Page 105 and 106: 5.2.4 Antenna support For the anten
Page 107 and 108: Components Young's moduli (GP a) Po
Page 109 and 110: Components Young's moduli (GP a) Po
Page 111 and 112: 5.3 Static analysis As described in
Page 113 and 114: Figure 5.9: Illustration of the com
Page 115 and 116: Figure 5.11: Maximal Von Mises stre
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Figure 5.12: First mode of OUFTI-1
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Figure 5.15: Precise PSD of Vega [5
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Chapter 6 Conclusions This master t
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provided for each method used. We h
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last versions of the Verication Con
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[13] Ph. LEDENT. "Design and Implem
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[40] "Dejond - Aluminum Catalog ".
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Appendix A Schemas of solar panels
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Appendix B Schemas of electronic ca
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Appendix C Fixations of the endless
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Appendix D Datasheet of the battery
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Master Thesis - OUFTI-1

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