“All these worlds are yours, except Europa. Attempt no landing there. Use them together. Use them in peace.” -2010: Odyssey Two, Arthur C. Clarke To Kathryn List of Papers This thesis is based on the following papers, which are referred to in the text by their Roman numerals. I Jonsson, J., Edqvist, E., Kratz, H., Almqvist, M., Thornell, G. (2010) Simulation, manufacturing, and evaluation of a sonar for a miniatur- ized submersible explorer. IEEE Transactions on Ultrasonics, Fer- roelectrics, and Frequency Control, 57(2), 490-495, DOI: 10.1109/TUFFC.2010.1429. II Jonsson, J., Lekholm, V., Kratz, H., Almqvist, M., Thornell, G. (2012) Enclosure-induced interference effects in a miniaturized sidescan sonar. IEEE Journal of Oceanic Engineering, In Press, Dig- itally published, DOI: 10.1109/JOE.2012.2188160. III Jonsson, J., Berglund, M., Kratz, H., Nguyen, H., Thornell, G. (2012) A compact system to extract topography information from scenes viewed by a miniaturized submersible explorer. Sensors & Actuators A, In Press, Digitally published, DOI: 10.1016/j.sna.2012.02.034. IV Jonsson, J., Ogden, S., Johansson, L., Hjort, K., Thornell, G. (2012) Acoustically enriching, large-depth aquatic sampler. Lab on a Chip, In Press, Digitally published, DOI: 10.1039/C2LC00025C. V Ogden, S., Jonsson, J., Thornell, G., Hjort, K. (2011) A latchable high-pressure thermohydraulic valve actuator. Sensors & Actuators A, In Press, Digitally published, DOI: 10.1016/j.sna.2011.11.027. VI Palmer, K., Jonsson, J., Nguyen, H., Thornell, G. (2012) Two- dimensional thermal velocity sensor for submersible navigation and minute flow measurements. Submitted to IEEE Sensors Journal. VII Jonsson, J., Smedfors, K., Nyholm, L., Thornell, G. (2012) Towards chip-based salinity measurements for small submersibles and bio- loggers. Submitted to Lab on a Chip. Author’s Contribution to the Publications Paper I Most of planning, experimental work, evaluation and writing. Paper II Most of planning, experimental work, evaluation and writing. Paper III Major of planning and evaluation, most of experimental work and writing. Paper IV Part of planning, major part of experimental work and evalua- tion and most of writing. Paper V Part of planning, experimental work, evaluation and writing. Paper VI Part of planning and evaluation, major part of experimental work and writing. Paper VII Most of planning, experimental work, evaluation and writing. Reprints were made with permission from the respective publishers. Contents Introduction ................................................................................................... 11 Submerged environments .............................................................................. 13 Oceans of life ............................................................................................ 13 Extreme environments .............................................................................. 14 Hydrothermal vent systems .................................................................. 15 Ice-covered oceans and lakes ............................................................... 16 Subglacial lakes ................................................................................... 17 Other targeted environments .................................................................... 19 Underwater caves ................................................................................. 19 Mines .................................................................................................... 20 Pipes ..................................................................................................... 21 Wrecks ................................................................................................. 21 Beyond the pale blue dot .......................................................................... 23 Worlds of interest ................................................................................. 23 Exploration .................................................................................................... 26 Manned deep-sea submersibles ................................................................ 27 Unmanned submersibles ........................................................................... 28 A brief history of ROVs ....................................................................... 29 Some ROVs on the market .................................................................. 30 Penetrating and probing ice ...................................................................... 30 Subglacial lake explorers .......................................................................... 32 The DADU vehicle ........................................................................................ 35 Hull design ................................................................................................ 36 Propulsion and attitude control ................................................................. 37 Communication ........................................................................................ 39 Control system .......................................................................................... 40 Navigation and attitude sensing ................................................................ 41 Power handling ......................................................................................... 42 Microsystems Technology ............................................................................ 43 Processing ................................................................................................. 44 Lithography .......................................................................................... 44 Thin film deposition ............................................................................. 45 Etching ................................................................................................. 46 Some relevant materials ............................................................................ 47 Silicon .................................................................................................. 47 Pyrex .................................................................................................... 47 PZT ...................................................................................................... 48 Paraffin ................................................................................................. 48 DADU Subsystems ....................................................................................... 49 Topography measurement system ............................................................ 49 Diffractive optics ................................................................................. 51 Realizing the lens ................................................................................. 51 Measuring principle using projected patterns ...................................... 52 Measurements ...................................................................................... 53 Side-scanning sonar .................................................................................. 54 Principle of acoustic imaging ............................................................... 55 The miniaturized side-scanning sonar ................................................. 57 Sampling particles .................................................................................... 61 Microfluidics ........................................................................................ 62 Manipulation of particles by acoustic forces ....................................... 62 Valves .................................................................................................. 63 Collecting the samples ......................................................................... 64 Building the sampling device ............................................................... 65 Testing the trap .................................................................................... 66 Conductivity, Temperature, and Depth measurements ............................ 67 The sensor chip .................................................................................... 68 Conductivity ......................................................................................... 68 Temperature ......................................................................................... 69 Depth .................................................................................................... 69 Flow sensor ............................................................................................... 70 Measurement principle ......................................................................... 70 The flow chip ....................................................................................... 71 Predicting the performance .................................................................. 71 Measuring ............................................................................................ 72 Discussion and Conclusions .......................................................................... 73 Outlook .......................................................................................................... 75 Summary in Swedish ..................................................................................... 76 Acknowledgements ....................................................................................... 79 References ....................................................................................................