Carbon based atomic oxygen sensors

Carbon-based sensors have been developed to measure the atmospheric neutral atomic oxygen (AO) flux experienced by spacecraft in low Earth orbit (LEO). Thick- and thin film carbon sensor elements were deposited on an alumina substrate between thick film gold tracks and silver palladium solder pads. AO flux is deduced by measuring resistance changes as the carbon film erodes, and applying a simple theory. Measured resistance increases during exposure in a ground-based AO facility compare favourably with theoretical predictions. These sensors appear to offer a number of advantages compared with similar silver-based sensors that have been flown previously, particularly for small satellite missions with significant mass/power constraints.