VfOx in GEER: Functional Test of a Venus Oxygen Fugacity Sensor

VfOx, which stands for “Venus Oxygen Fugacity” is the DAVINCI mission’s Student Collaboration Experiment (SCE); a small single- objective sensor used to measure the partial pressure of molecular oxygen in Venus’ lower atmosphere. Through the mission timeline, VƒOx will be designed, fabricated, tested, operated, and results analyzed by undergraduate and graduate students mentored by the DAVINCI team in partnership with Johns Hopkins University and other institutions.

The simple principal of VƒOx is a ceramic O2 sensor derived from common applications, utilizing diffusion of O-2 ions between a standard (PdO) inside the sensor and the target atmosphere measured by a mW level voltage that depends directly on the standard/sample fO2 ratio.

A 60-day environmental test of a prototype design of the sensor was conducted at the Glenn Extreme Environment Rig (GEER) from August to October of 2022, in which VƒOx (Fig. 1) was placed inside the experimental chamber (Fig. 2) and brought to Venus surface temperature (460 °C) and pressure (92 bar) conditions, in a Venus like atmosphere (96.5% CO2, 3.5% N2) that included trace gases like SO2, maintained by occasional “boosts” of extra gas during the experimental run.