WE PROPOSE A FOUR YEAR SUBORBITAL-CLASS RESEARCH PROGRAM TO DEVELOP LAUNCH AND OPERATE THE ASTROPHYSICS RESEARCH TESTBED AND UV EMISSION MAPPING IMAGING SPECTROGRAPH (ARTEMIS): A 6U CUBESAT THAT WILL ADDRESS TWO KEY QUESTIONS IN ASTRONOMY: .HOW DO GALAXIES PROVIDE IONIZING RADIATION TO THE IGM? THE TRANSITION FROM A NEUTRAL TO AN IONIZED INTERGALACTIC MEDIUM (IGM) WAS ONE OF THE KEY MILESTONES IN COSMIC STRUCTURE FORMATION. FINDING THE IONIZING SOURCES - GALAXIES AND AGN - IS A CENTRAL GOAL OF THE JAMES WEBB SPACE TELESCOPE (JWST) BUT EVEN THIS FLAGSHIP CANNOT SOLVE ONE CRITICAL ASPECT OF THE PROBLEM: HOW MUCH OF THIS RADIATION ACTUALLY ESCAPES GALAXIES TO RE-IONIZE THE IGM? WEBB CANNOT DETECT THE IONIZING RADIATION ITSELF THROUGH THE OPAQUE HIGH-Z IGM SO USERS WILL INSTEAD USE REDSHIFTED UV/OPTICAL EMISSION LINES AS PROXIES. THESE PROXIES MUST BE CALIBRATED WITH DIRECT MEASUREMENTS OF IONIZING RADIATION ESCAPE IN A SAMPLE OF GALAXIES AT LOWER REDSHIFT. ARTEMIS WILL DIRECTLY MEASURE THE IONIZING SPECTRUM IN 100 0.15<Z<0.3 GALAXIES AND AGN A SAMPLE THAT WILL SURPASS IN NUMBER AND PRECISION ALL IONIZING ESCAPE MEASUREMENTS TO DATE AND PROVIDE CRITICAL INTERPRETIVE TOOLS FOR CORE JWST SCIENCE. .WHAT CONTROLS THE MASS ENERGY AND CHEMICAL FLOWS WITHIN GALAXIES? OB STARS DOMINATE THE IONIZATION AND KINEMATIC DRIVERS OF GALACTIC DISKS THROUGH THEIR INTENSE RADIATION FAST STELLAR WINDS AND METAL DISPERSAL IN SUPERNOVAE; BUT HOW DO THESE PROCESSES INTERACT TO DRIVE THE EVOLUTION OF GALAXIES? ARTEMIS WILL TRACE FEEDBACK IN ITS EARLIEST STAGES USING UNIQUE FAR-UV DIAGNOSTICS (FUV: 1000 - 1600 ANGSTROMS) AND A NOVEL SPECTRAL IMAGING OBSERVING MODE TO CREATE MULTI-DIMENSIONAL DATA CUBE MAPS OF MORE THAN 50 LOCAL STAR FORMING REGIONS AND SUPERNOVA REMNANTS IN THE MILKY WAY AND MAGELLANIC CLOUDS. THIS SURVEY WILL QUANTIFY THE PHYSICS OF RADIATIVE AND KINETIC ENERGY INJECTION INTO THEIR HOST GALAXIES AND PROVIDE GROUND-TRUTH TO SUB-GRID PHYSICAL MODELS IN HYDRODYNAMICAL SIMULATIONS. .ARTEMIS IS DESIGNED TO CARRY OUT THESE ASTROPHYSICALLY COMPELLING SPECTRAL SURVEYS WHILE SERVING AS A DEMONSTRATION TESTBED FOR THE LUVOIR SURVEYOR - MATURING AND FLIGHT-QUALIFYING TECHNOLOGY IDENTIFIED AS PRIORITY ONE NEEDS IN THE 2017 NASA COSMIC ORIGINS PROGRAM ANNUAL TECHNOLOGY REPORT. THE ADVANCED OPTICAL COATINGS AND NEXT-GENERATION PHOTON-COUNTING MICROCHANNEL PLATE (MCP) DETECTOR IN THE ARTEMIS DESIGN REPRESENT A PARADIGM SHIFT FOR ASTRONOMY IN THE FUV ENABLING MORE OPTICAL ELEMENTS AND EXCEPTIONALLY LOW ON-ORBIT BACKGROUNDS WITHOUT THE CRIPPLING THROUGHPUT LOSSES THAT WOULD OCCUR WITH CONVENTIONAL TECHNOLOGIES. OUR EXTENSIVE ON-ORBIT CALIBRATION PROGRAM WILL PROVIDE CRITICAL IN SITU MEASUREMENTS OF THEIR STABILITY AND PERFORMANCE AHEAD OF FORMAL ADOPTION BY LUVOIR HABEX OR OTHER NASA LARGE- PROBE- OR EXPLORER-CLASS MISSIONS. ARTEMIS WILL LEVERAGE THESE RECENT PRODUCTS OF THE APRA SAT AND ROMAN TECHNOLOGY FELLOWSHIP PROGRAMS TO ACHIEVE SENSITIVITIES COMPARABLE TO OR EXCEEDING PREVIOUS FUV EXPLORER-CLASS MISSIONS IN A CUBESAT ENVELOPE. .THE ARTEMIS INSTRUMENT IS COMPRISED OF A RECTANGULAR CASSEGRAIN TELESCOPE FEEDING A COMPACT LOW RESOLUTION (R ~ 1500) IMAGING SPECTROGRAPH. THE SCIENCE INSTRUMENT IS INCORPORATED INTO A BLUE CANYON TECHNOLOGIES SPACECRAFT BUS THAT PROVIDES POWER COMMAND AND DATA HANDLING ATTITUDE CONTROL AND COMMUNICATIONS. CALIBRATION AND TESTING WILL OCCUR IN EXISTING UNIVERSITY OF COLORADO (CU) UV SPACE-INSTRUMENT FACILITIES ALONGSIDE OTHER NASA SMD MISSIONS. ARTEMIS WILL BE DEVELOPED IN THE FRAMEWORK OF CU'S STUDENT LED SPACE SCIENCES PROGRAM WHERE UNDERGRADUATE GRADUATE AND POSTDOCTORAL TRAINING IS PARAMOUNT. .