Miniaturized ring-down spectrometer for CubeSat-based planetary science

A robust, miniaturized cavity ring-down spectrometer has been developed as a laboratory demonstration model for future CubeSat deployments of near- and mid-infrared spectrometers for in situ planetary science. The spectrometer is compact enough to ensure compatibility with standard CubeSat spacecraft buses, with a probed gas volume of less than 2.5 cc to ease mass, volume, and power requirements of sample gas handling subsystems. When operated at 1.39 μm for water vapor isotope measurements, a noise-equivalent absorption coefficient of 3.7×10^-9  cm^-1 Hz^-1/2 is obtained. Oxygen isotope measurements were performed to demonstrate scanning performance. The spectrometer has been designed to use only components with functional equivalents throughout the 1-5 μm range to maintain flexibility across a wide array of planetary science targets. Preliminary results from a 3.27 μm implementation intended for methane measurements are also presented.