The Mars analytical chemistry experiment

Future missions to Mars will offer the opportunity to continue the search for organic molecules accessible from the surface, and to better quantify the cycling of volatile elements through geochemical pathways. This presentation describes an analytical instrument suite that is designed to measure elemental, isotopic, and potential organic signatures contained in the atmosphere and near surface reservoirs on Mars. The Mars analytical chemistry experiment (MACE) combines two unique mass-spectrometer-based instruments to accomplish these measurements. The first instrument combines a sample handling system with a reusable pyrolysis oven for processing solid materials. Evolved volatile gases from the pyrolyzer are either oxidized for elemental analysis, or sent through a preconcentrator into a 2D gas chromatograph for separation of organics. The processed gas stream is then sent to a high resolution dynamic time-of-flight mass spectrometer for detection. The second instrument is designed primarily for direct atmospheric measurements, using a combination of catalyst beds, getters, and cryogenic traps to separate and concentrate species of interest, such as noble gases. Concentrated gases are subsequently detected with a second, dedicated static mass spectrometer to avoid possible contamination from the pyrolysis of organics in the first process. A breadboard version of each of these instruments has been demonstrated in the laboratory. In this presentation, we discuss the design, applicability, and capabilities of the MACE suite in more detail