This proposal addresses NASA astrobiology objectives, particularly the need for a compact instrument capable of in situ isotopic measurements. We propose the detailed conceptual development of a device for analyzing key isotopic composition in surface materials without sample preparation. We will combine absorption spectroscopy with laser induced vaporization of solid samples for high-resolution isotopic measurements. An immediate focus is on Mars but our concept is also highly germane to other applications relevant to bio- and geochemical objectives. We will evaluate accuracy, sensitivity, and resolution of our technology for isotopic detection of the key elements associated with signs of life (C, S, H, O) in solid materials. All essential design components of the proposed analyzer have been separately developed and demonstrated in very compact form for other applications. In the Phase I, we will develop technology for measuring sulfur isotope ratios in condensed samples. In the Phase II, we will demonstrate the overall performance of the proposed technique and deliver a breadboard prototype instrument. Commercial systems based on the Phase II prototype will be developed and marketed during Phase III.