WE PROPOSE A FOUR YEAR SUBORBITAL-CLASS RESEARCH PROGRAM TO DEVELOP LAUNCH AND OPERATE A CUBESAT MISSION TO STUDY THE ATMOSPHERIC PROPERTIES OF PLANETS ORBITING OTHER STARS. EXOPLANETS IN SHORT-PERIOD ORBITS (PROT = 1 5 DAYS) PROVIDE A UNIQUE OPPORTUNITY TO OBSERVE PHENOMENA CRITICAL TO THE DEVELOPMENT AND EVOLUTION OF OUR OWN SOLAR SYSTEM WRIT LARGE INCLUDING ATMOSPHERIC MASS-LOSS INTERACTION WITH THE HOST STAR AND POSSIBLY EVEN PLANETARY MAGNETISM. HOT JUPITERS AND HOT NEPTUNES ARE LABORATORIES FOR STUDYING THE PHYSICS OF ATMOSPHERIC ESCAPE. OWING TO THEIR LARGE SIZES AND SHORT-PERIODS THE PHYSICS OF ATMOSPHERIC MASS-LOSS CAN BE STUDIED AT WITH A DEDICATED SMALL INSTRUMENT. OBSERVATIONS OF SHORT-PERIOD PLANETS HAVE FOUND THEM TO BE GREATLY INFLATED EXTENDED TO SEVERAL PLANETARY RADII IN SOME CASES. SYSTEMS WITH LIGHT CURVES SHOWING LATE-EGRESS RELATIVE TO THEIR OPTICAL TRANSIT HAVE BEEN MODELED AS COMET-LIKE TAILS THAT FORM AS THE PLANET S EXTENDED ATMOSPHERE EXTENDS BEYOND THE ROCHE LOBE AND ESCAPES INTO INTERPLANETARY SPACE. EARLY-INGRESS OBSERVATIONS MAY ALSO INDICATE RAPID MASS-LOSS BUT HAVE BEEN ALTERNATIVELY INTERPRETED AS EVIDENCE FOR A MAGNETICALLY SUPPORTED BOW SHOCK AHEAD OF THE PLANET S ORBITAL MOTION. THESE PROCESSES CANNOT BE OBSERVED IN BROAD-BAND OPTICAL LIGHT CURVES (E.G. WITH KEPLER). THE COLORADO ULTRAVIOLET TRANSIT EXPERIMENT (CUTE) IS DESIGNED TO SPECTRALLY ISOLATE DIAGNOSTIC ATOMIC AND MOLECULAR TRANSITIONS ARISING WITHIN THESE ATMOSPHERES TO STUDY THE PHYSICS OF ATMOSPHERIC MASS-LOSS AND POSSIBLY DETECT THE PRESENCE OF MAGNETIC FIELDS ON EXOPLANETS. THE KEYS TO UNLOCKING THE DIAGNOSTIC POTENTIAL OF THESE SYSTEMS ARE SPECTRAL COVERAGE IN THE APPROPRIATE BANDPASS AND THE ABILITY TO FOLLOW THE SYSTEMS FOR SEVERAL ORBITAL PERIODS. CUTE IS DESIGNED TO PROVIDE EXACTLY THAT LOW RESOLUTION SPECTROSCOPY OF CRITICAL ATMOSPHERIC TRACERS (FE II MG II MG I OH) THAT ARE INACCESSIBLE FROM THE GROUND AND A DEDICATED MISSION ARCHITECTURE THAT ENABLES THE NECESSARY FACTOR-OF-TWENTY INCREASE IN SURVEY TIME (RELATIVE TO LARGE TREASURY PROJECTS WITH THE HUBBLE SPACE TELESCOPE) REQUIRED TO CHARACTERIZE THE ATMOSPHERIC STRUCTURE OF THESE WORLDS. THE CUTE INSTRUMENT IS COMPRISED OF A CASSEGRAIN TELESCOPE (190MM 85MM F/2.5 PRIMARY) FEEDING A COMPACT LOW RESOLUTION (R = 2000) SPECTROGRAPH OPERATING FROM 2500 3500 . THE SPECTROGRAM IS RECORDED ON A UV-OPTIMIZED E2V CCD. ONBOARD DATA REDUCTION IS PERFORMED AND DATA PRODUCTS ARE RELAYED TO AN EXISTING GROUND STATION AT THE UNIVERSITY OF COLORADO. THIS STATION CURRENTLY SERVES AS THE GROUND SEGMENT FOR SEVERAL CUBESAT PAYLOADS BUILT AND OPERATED BY STUDENTS AND RESEARCHERS ON CAMPUS. THE SCIENCE INSTRUMENT IS INCORPORATED INTO A 6U FORM FACTOR WITH A BUS PROVIDED BY BLUE CANYON TECHNOLOGIES. THE BLUE CANYON BUS PROVIDES POWER COMMAND AND DATA HANDLING ATTITUDE CONTROL AND COMMUNICATIONS. BLUE CANYON AND THE INSTRUMENT TEAM AT COLORADO ARE LOCATED WITHIN 3 MILES OF EACH OTHER FACILITATING COLLABORATION DURING THE FABRICATION AND INTEGRATION OF THE CUTE PAYLOAD. CALIBRATION AND TESTING WILL OCCUR IN THE EXISTING ULTRAVIOLET SPACE-INSTRUMENT CHARACTERIZATION FACILITIES AT COLORADO. CUTE WILL BE DEVELOPED IN THE FRAMEWORK OF A UNIVERSITY-LED PROGRAM WHERE UNDERGRADUATE GRADUATE AND POSTDOCTORAL TRAINING IS PARAMOUNT. THE UNIVERSITY OF COLORADO HAS A LONG HISTORY OF TRAINING NASA S FUTURE LEADERS IN SPACE SCIENCES AND THE CUTE PROGRAM WILL EXTEND THAT HERITAGE TO A NEW GENERATION OF INVESTIGATORS WITH ACCESS TO SMALL SATELLITE OPPORTUNITIES.