UNDERSTANDING THE FORMATION AND EVOLUTION OF GALAXIES OVER COSMIC TIME IS ONE OF THE FOREMOST GOALS OF ASTROPHYSICS AND COSMOLOGY TODAY. THE COSMIC STAR FORMATION RATE HAS UNDERGONE A DRAMATIC EVOLUTION OVER THE COURSE OF THE LAST 14 BILLION YEARS AND DUSTOBSCURED STAR FORMING GALAXIES (DSFGS) ARE A CRUCIAL COMPONENT OF THIS EVOLUTION. A VARIETY OF IMPORTANT BRIGHT AND UNEXTINCTED DIAGNOSTIC LINES ARE PRESENT IN THE FAR-INFRARED (FIR) WHICH CAN PROVIDE CRUCIAL INSIGHT INTO THE PHYSICAL CONDITIONS OF GALAXY EVOLUTION INCLUDING THE INSTANTANEOUS STAR FORMATION RATE THE EFFECT OF AGN FEEDBACK ON STAR FORMATION THE MASS FUNCTION OF THE STARS METALLICITIES AND THE SPECTRUM OF THEIR IONIZING RADIATION. FIR SPECTROSCOPY IS TECHNICALLY DIFFICULT BUT SCIENTIFICALLY CRUCIAL. THE FIR WAVEBAND IS IMPOSSIBLE TO OBSERVE FROM THE GROUND AND SPANS A CRUCIAL GAP IN THE SPECTROSCOPIC COVERAGE BETWEEN THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY (ALMA) IN THE SUB/MM AND THE JAMES WEBB SPACE TELESCOPE (JWST) IN THE MID-IR. STRATOSPHERIC BALLOONS OFFER A PLATFORM WHICH CAN OUTPERFORM CURRENT INSTRUMENT SENSITIVITIES AND ARE THE ONLY WAY TO PROVIDE LARGE-AREA WIDE BANDWIDTH SPATIAL/SPECTRAL MAPPING AT FIR WAVELENGTHS. .WE PROPOSE AN AGGRESSIVE PROGRAM OF INSTRUMENTATION DEVELOPMENT AND EXPERIMENTAL STUDY CALLED THE SPECTROSCOPIC TERAHERTZ AIRBORNE RECEIVER FOR FAR-INFRARED EXPLORATION (STARFIRE) WITH THE GOAL OF DEMONSTRATING THE KEY TECHNICAL MILESTONES NECESSARY FOR FIR SPECTROSCOPY. STARFIRE WILL PROVIDE A TECHNOLOGICAL STEPPING STONE TO THE FUTURE SPACE-BORNE INSTRUMENTATION SUCH AS THE ORIGINS SPACE TELESCOPE (OST FORMERLY THE FAR-IR SURVEYOR) OR A PROBE MISSION. STARFIRE WILL ADDRESS THE TWO KEY TECHNICAL ISSUES NECESSARY TO ACHIEVE THIS: 1) LOW-EMISSIVITY HIGH-THROUGHPUT TELESCOPE AND SPECTROMETER OPTICS FOR THE FIR; 2) BACKGROUND-LIMITED DETECTORS IN LARGE FORMAT ARRAYS SCALABLE TO>10 000 PIXELS. WE WILL DO THIS BY CONSTRUCTING AN INTEGRAL-FIELD SPECTROMETER FROM 240 - 420 MICRONS COUPLED TO A 2-METER LOW-EMISSIVITY CARBONFIBER TELESCOPE. THE DEVELOPMENT OF THE OPTICS WILL UTILIZE THE CAPABILITIES OF THE ARIZONA STEWARD OBSERVATORY MIRROR LAB AND THE UNIQUE EXPERTISE OF OUR SPECTROSCOPIC EXPERTS TO CREATE HIGH-THROUGHPUT OPTICS. FOR THE DETECTORS WE WILL LEVERAGE THE HIGHLY ADVANCED DEVELOPMENT WORK OF THE CALTECH / JPL GROUP TO DEVELOP AND FIELD KINETIC-INDUCTANCE DETECTORS (KIDS). KIDS REPRESENT THE MOST PROMISING ROUTE TO ECONOMICAL LARGE FORMAT SUBMILLIMETER DETECTOR ARRAYS. .IN ADDITION TO THE DEVELOPMENT AND DEMONSTRATION OF CRUCIAL TECHNOLOGIES FOR THE FIR STARFIRE WILL PERFORM GROUNDBREAKING SCIENCE. WE WILL SURVEY TWO 0.1 SQUARE DEGREE FIELDS CENTERED ON GOODS-S AND THE SOUTH POLE TELESCOPE DEEP FIELD BOTH OF WHICH HAVE RICH ANCILLARY DATA. SCIENTIFICALLY WE WILL: 1) OBTAIN SPECTROSCOPIC LINE DETECTIONS OF ~100 GALAXIES IN THE ATOMIC FINE STRUCTURE LINES [CII](158 MICRONS) (AT 0.5<Z<1.5) [NII](205 MICRONS) (AT 0.2<Z<1 ) [OI](63 MICRONS) (AT 2.8<Z<5.7 ) AND [OIII](88 MICRONS) (AT 1.7<Z<3.8); 2) ESTABLISH THE MEAN STAR FORMATION RATE (PROPORTIONAL TO [CII] LUMINOSITY) METALLICITIES (PROPORTIONAL TO THE [CII]/[NII] RATIO) AND AGN CONTENT (PROPORTIONAL TO THE [OIII] LUMINOSITY) OF GALAXIES USING A STACKING ANALYSIS OF KNOWN SOURCES IN THE FIELD; 3) PRODUCE DEEP MAPS OF THE 3D STRUCTURE OF THE UNIVERSE BY REDSHIFT TOMOGRAPHY (''INTENSITY MAPPING'') WITH [CI] AND [CII] X [NII] CROSS-SPECTRA TO CONSTRAIN THE COSMIC STAR FORMATION HISTORY AT COSMIC NOON AND LAY THE IMPORTANT GROUNDWORK FOR EXTENDING THIS TECHNIQUE TO EVEN HIGHER REDSHIFTS TO EVENTUALLY EXPLORE THE EPOCH OF REIONIZATION. .WE NOTE THERE IS SIGNIFICANT DISCOVERY POTENTIAL WITH STARFIRE SINCE IT WILL BE PROBING AN UNDER-EXPLORED WAVELENGTH RANGE WITH UNPRECEDENTED SENSITIVITY USING A NEW ASTROPHYSICAL TECHNIQUE. STARFIRE IS CRITICAL TO THE NASA ROADMAP OF DEVELOPING TECHNOLOGIES FOR A FUTURE FIR SPACE MISSION. .