Mechanical Design and Thermal Analysis of the MoreBac Experiment

Sammanfattning: Sending bacteria to space is a further step withinthe framework of transporting humans to distant locations inspace. This can build a knowledge platform of how the bacteriabehaves in the space environments, in order to be able to functionin the long term as a LLS (long term life support system), i.ea mini ecology for the space station that handles waste (gas,liquid and solid) and transforms it into food, water and oxygen.By constructing a bacterial experiment (MoreBac) in a smallsatellite and thermally simulating it in space environment, itcan aid future projects performed in similar but larger scales.To visualize the experiment in presentations, a CAD-model ofthe experiment will be designed and constructed in SIEMENSSolid Edge. The thermal analysis is made in Airbus SYSTEMAThermica and will help show on the critical problem, which isto maintain suitable temperature conditions on the microfluidicchip inside the experiment. By performing the simulations, onecan assure that the design is suitable and that the heat gradientis in required intervals for different components. The CADmodelwas designed in a sandwich layout and consist of twoprinted circuit boards, one microfluidic chip and one reservoir.Not specified components of the experiment was not used in theCAD- model since they where still in early development. Thethermal analysis of the experiment was studied in a steady stateenvironment, with boundary conditions of 5˝C in the cold caseand 30˝C in the hot case, which means that the time variablewas not considered. Three configurations of heat dissipation weremade; 16 nodes at the illumination board with 0,05 W each, 16nodes at the detection board with 0,05 W each and finally 36nodes on both PCBs together with 0,025 W each. In the hot case,the microfluidic chip reaches temperatures between 34, 16˝C and42, 15˝C when 0,8 W is equally divided to both PCBs. In thecold case, the microfluidic chip reaches temperatures between13, 82˝C and 22, 32˝C with the same heat distribution as thehot case.