Design of a Level Sensing System for the Propellant Tank of a Microlauncher

The projects presents the development process of a liquid level sensing
system for the use within the propellant tanks of a launch vehicle. Whereas many
recent launchers use discrete level sensing systems to indicate the amount of fuel on
defined spots like fill-stop and engine cut-off, in this report a continuous capacitance
based sensor probe is described. An accurate knowledge of the propellant level can
serve as input for the throttling of the propellant valves to account for changes in
the oxidizer-fuel ratio and therefore helps optimising the operation of the rocket
engine. Furthermore, the more precise the amount of fuel is known, the less unused
propellant mass will remain allowing a cost and mass optimisation for each mission.
Additionally to the increased vehicle performance, the sensor designs described aim
to have comparably low mass and cost.