SCIENTIFIC GOALS AND OBJECTIVES -- UNDERSTANDING THE PHYSICS AND CHEMISTRY OF COMETS CAN LEAD TO SIGNIFICANT IMPROVEMENTS IN OUR KNOWLEDGE OF THE FORMATION OF THE SOLAR SYSTEM BECAUSE COMETS ARE THE LEAST ALTERED REMNANTS OF THAT FORMATION. STUDIES OF COMETS CONSTRAIN THE PHYSICAL CONDITIONS IN THE SOLAR NEBULA THE DYNAMICAL EVOLUTION OF THE DISK AND OF PLANETESIMALS AND THE CHEMICAL EVOLUTION OF THESE BODIES. THE PRIMARY OBJECTIVE OF THIS PROGRAM IS TO DEVELOP FUNDAMENTAL INFORMATION ON COMETARY CHEMICAL ELEMENTAL AND ISOTOPIC COMPOSITION. THESE ABUNDANCES CAN THEN BE USED AS INPUTS FOR FUTURE MODELS OF THE EARLY SOLAR NEBULA. THIS PROGRAM IS A CONTINUATION OF OUR LONG-STANDING SPECTROSCOPIC STUDY OF COMETS. WE HAVE STUDIED COMETS AS INDIVIDUAL BODIES AND AS MEMBERS OF A LARGE CLASS OF OBJECTS THAT FORMED IN THE OUTER SOLAR NEBULA. STUDIES OF INDIVIDUAL BODIES ALLOW US TO DETERMINE THEIR NATURE. AS OUR DATABASES BUILD WE CAN DRAW CONCLUSIONS ABOUT THE WHOLE POPULATION. THIS PROPOSAL PRESENTS A TWO-PRONGED APPROACH. WE WILL OBTAIN NEW SPECTROSCOPIC OBSERVATIONS OF COMETS AT HIGH SPECTRAL RESOLUTION IN THE OPTICAL. WE WILL THEN USE VARIOUS ANALYSIS TOOLS TO UNDERSTAND THE ABUNDANCES OF OBSERVED MOLECULES TO STUDY THE KINETIC TEMPERATURE OF SOME MOLECULES AND THE PHOTOCHEMISTRY OF OTHERS AND TO COMPARE WITH DATA OBTAINED BY COLLEAGUES TO DETERMINE THE NATURE OF COMETS AND THEIR ROLE IN THE FORMATION OF PLANETS IN THE EARLY SOLAR SYSTEM. METHODOLOGY AS IN PRIOR YEARS OUR APPROACH TO UNDERSTANDING COMETS IS SPECTROSCOPIC. WE WILL STUDY COMETS AT OPTICAL WAVELENGTHS. WE WILL USE THE 2DCOUDE SPECTROGRAPH AT MCDONALD THE ARCES SPECTROGRAPH AT APACHE POINT THE HIRES SPECTROGRAPH AT KECK OR THE GRACES SPECTROGRAPH AT GEMINI TO OBSERVE THE STRUCTURE OF THE MOLECULAR BANDS. COUPLED WITH SPECTRAL SYNTHESIS MODELS WE CAN DETERMINE THE RELATIVE INTENSITIES OF LINES TO MEASURE THE ISOTOPE RATIOS KINETIC TEMPERATURES ORTHO/PARA RATIOS AND ABUNDANCES OF SPECIES. WE WILL AUGMENT OUR OPTICAL SPECTRA WITH OBSERVATIONS OBTAINED IN THE IR BY OUR COLLABORATORS. DURING THE 2017 2019 TIME FRAME OF THIS PROPOSAL WE HAVE MANY COMETS WITH V MAGNITUDES OF 10 OR BRIGHTER SUITABLE FOR SUCH STUDIES. UNUSUALLY MOST OF THESE COMETS ARE JUPITER FAMILY COMETS. WE ANTICIPATE THAT MORE OORT CLOUD COMETS WILL BE ADDED TO THIS LIST WITH DISCOVERIES OF NEW OBJECTS. RELEVANCE TO NASA PLANETARY SCIENCE THIS PROPOSAL IS RESPONSIVE TO THE NASA OBJECTIVES AND GOALS OUTLINED IN THE ROSES 2016 FOR PLANETARY SCIENCE AND FOR THE SOLAR SYSTEM OBSERVATIONS PROGRAM BY OBTAINING NEW SPECTRA OF COMETS TO COUPLE WITH EXTANT OBSERVATIONS. WITH THESE DATA WE CAN ADDRESS KEY NASA QUESTIONS: HOW DID THE OBJECTS IN THE SOLAR SYSTEM FORM AND EVOLVE? WHAT ARE THE CHEMICAL AND PHYSICAL PROCESSES ACTIVE IN OUR SOLAR SYSTEM?