Measurement of 5-eV atomic oxygen using carbon based films: preliminary results

Carbon-based sensors have been developed to measure the atmospheric neutral atomic oxygen (AO) flux experienced by spacecraft in low Earth orbit. Thin- and thick-film carbon sensor elements were deposited onto 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. A wide range of responses were observed that are dependent on the deposition process and post deposition annealing. The deposition methods used were dc magnetron sputtering, e-beam evaporation, and screen-printing. The sensors tested compare favorably with similar silver-based sensors that have been flown previously on small satellite missions with significant mass/power constraints.