March 28, 2019



Measurement of the composition of the lower stratosphere plays an important role in research of the atmosphere. Novel miniaturised sensors for ozone (solid state electrolyte) and relative atmospheric humidity (resistive) are to be tested under real operating conditions aboard the BEXUS platform. Solid state electrolytes are occasionally noted for their robustness and short response time, although commercially available miniaturised sensors exhibit, amongst other things, particular sensitivity to fluctuations in ambient humidity. The use of Nafion as an electrolyte however eliminates this sensitivity, as it requires moisture to function as an ionic conductor [1]. The functional principle of the humidity sensor is based on observing the variation of the electrical properties of a network of multi-walled carbon nanotubes (MWCNT) embedded in a Nafion matrix, which has the interesting the property of absorbing water up to 30 wt% water. This enlarges the bond interfaces between the individual carbon nanotubes (CNT). Additionally, molecules on the surface of the CNT are absorbed, which causes the electrical resistance to rise. The permeability of water through Nafion is dependant on the partial pressure, through which the response time of the sensor decreases significantly. The sensors are heated in order to guarantee constant boundary conditions. The multilayer construction of the sensors is carried out using cost-effective thick-film technology. Various layer configurations are to be tested during the mission, before and after which their characteristics will be examined on a test bench at TU Dresden’s Institute of Aerospace Engineering.


Nils Hensch Project leader, outreach
Arno Gerhardt Command and Data handling Systems,
Electrical Power System
Elisabeth Berka Structures, mechanics
Frank Windeck Command and Data handling Systems,
Communication System
Lucas Nöller Command and Data handling Systems,
Communication System
Lukas Dils Structures, mechanics
Maxime Monette Thermal Control System
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