Development of a Compact, Lightweight, Passive Fabry-Perot Radiometer for Measurements of Trace Gases in the Martian Atmosphere

Progress on the development of a differential radiometer based upon the Fabry-Perot interferometer (FPI) for methane (CH₄), water vapor (H₂O) and formaldehyde (CH₂O) detection in the atmosphere of Mars is presented. The proposed FPI based instrument is designed to make absorption measurements of trace gases in the Martian atmosphere. The measurements can be made from a satellite platform using nadir and limb viewing modes of operation or from a ground platform such as a lander in a direct sun viewing mode. The FPI technique offers a unique combination of high spectral resolution enabling great specificity with high optical throughput permitting a large signal to noise ratio. A version of this instrument for measuring column CO₂, O₂, and H₂O vapor on Earth has been highly developed at Goddard over the last five years and has had extensive testing from both ground and aircraft platforms. The instrument has been further advanced through an ISAL (Instrument Synthesis and Analysis Lab) studies to reduce the size and power requirements to be more appropriate for a Mars mission.