The isotope and gas sensor resulting from this project will be developed to support efforts to search for evidence of life on future NASA missions. The research is specifically relevant to NASA Objective 2.3 which is to "Ascertain the content, origin, and evolution of the solar system and the potential for life elsewhere," as well as NASA Astrobiology Roadmap Goal 7: "Determine how to recognize signatures of life on other worlds and on Earth." In fact, NASA Astrobiology Roadmap Objective 7.1 is to "Learn how to recognize and interpret biosignatures which, if identified in samples from ancient rocks on Earth or from other planets, can help to detect and/or characterize ancient and/or present-day life." The anticipated technology would also be useful for the exploration of the Moon, asteroids, primitive meteorites, comets, and interplanetary dust particles. The relatively small size of the system will enable it to be inserted into a range of missions including landers and rovers. The capillary absorption spectrometer (CAS) at the heart of the system will also provide a new high precision, ultra-low-volume sensor relevant to a range of other NASA applications. These include water isotope ratio measurements, atmospheric sensing of Earth and other planets, environmental sensing from a small UAV, analysis of soil bacteria related to Carbon cycle, as well as full elemental analysis of various microscopic-sized samples and organisms. The CAS sensor to be developed under this project will provide an extremely attractive alternative to both isotope ratio mass spectrometers (IRMS) and cavity ring down spectrometers (CRDS). The CAS will be relatively inexpensive, require only picomoles of material, and be much smaller than competing systems. CAS sensors will fill niche markets in forensic analysis, environmental sensing, human breath analysis, and industrial process control. This STTR will lead to a new class of sensors, not just a modification of an existing concept. The resulting ultra-small volume sensors could compete with and complement current commercial sensors, and potentially open up new opportunities to perform real-time, in-situ analysis of trace molecules and stable isotopes in remote and/or sample-limited situations.