Flexible Assemblies of Electrocapacitive Volume Tomographic Sensors for Gauging Fuel of Spacecraft

Gauging propellant fuel of spacecraft in outer space has been an issue, because their liquid fuels tend to float, slosh, adhere to the tank walls, and form bubbles under low-gravity conditions. For this reason, conventional fuel gauging techniques may not be an accurate way of gauging the fuel in space. In this paper, we report a flexible monolithic printed assembly of electrocapacitive volume tomography sensors, which can reconstruct the three-dimensional shape of the propellant fuel and promise to overcome the deficiencies of conventional fuel-gauging techniques. A commercial printer was used to transfer the patterns of the electrocapacitive volume tomography sensors and electric connections onto a flexible laminated copper. Feasibility of the three-dimensional volumetric reconstruction on water and a heat-transfer fluid showed that the National Institute of Standards and Technology’s flexible electrocapacitive volume tomography sensor system could successfully sense the changes in electrocapacitance due to the presence of these liquids. Based on those measured electrocapacitive volume tomography data, the three-dimensional shape of the fluid was reconstructed and matched with the real one used during laboratory testing.