EXCITING RESULTS FROM NASA'S KEPLER MISSION INDICATE THAT AS MUCH AS 100% OF SUN-LIKE STARS HAVE EARTH-SIZED PLANETS ORBITING WITHIN THEIR HABITABLE ZONE. SUBSTANTIAL RECENT PROGRESS HAS BEEN MADE IN UNDERSTANDING HOW SPECTROSCOPIC OBSERVATIONS OF SUCH PLANETS CAN BE USED TO REVEAL ATMOSPHERIC COMPOSITION. SIMULTANEOUSLY NEW RESULTS HAVE REVEALED HOW ATMOSPHERIC COMPOSITION CAN INDICATE SIGNS OF CHEMICAL DISEQUILIBRIUM (WHICH CAN BE A BASIC SIGNATURE OF LIFE). WE PROPOSE TO PAIR THESE TWO APPROACHES BY BUILDING A FIRST OF ITS KIND TOOL FOR DETECTING BIOSIGNATURE GASES AND SIGNS OF ATMOSPHERIC CHEMICAL DISEQUILIBRIUM FOR EXOPLANETS. OUR NOVEL INVERSE MODEL FOR DETECTING KEY SIGNATURES OF LIFE WILL THEN BE APPLIED TO BOTH REAL AND SIMULATED OBSERVATIONS OF EARTH. FINALLY USING AN EXISTING MODELING SUITE WE WILL GENERATE AND INTERPRET SIMULATED OBSERVATIONS OF EARTH THROUGH TIME RELEVANT TO UNDER-STUDY NASA MISSION CONCEPTS TO ENABLE AN UNDERSTANDING OF HOW EASY (OR HARD) IT WOULD BE FOR THESE FUTURE MISSIONS TO DETECT DIVERSE SIGNS OF LIFE FOR DISTANT EARTH-TWINS AT KEY STAGES OF GEOLOGICAL BIOLOGICAL AND ATMOSPHERIC EVOLUTION. OUR PROPOSED WORK IS RELEVANT TO BOTH NASA'S STRATEGIC PLAN 2018 AND TO THE EXOBIOLOGY PROGRAM. WE AIM TO SHED LIGHT ON THE VARIOUS SIGNATURES OF LIFE THAT APPEAR IN EARTH'S EVOLVING SPECTRUM AND WE WILL ADDRESS STRATEGIES FOR OBSERVING THESE BIOSIGNATURES FOR EARTHLIKE EXOPLANETS. BOTH OF THESE GOALS ARE RELEVANT TO NASA'S STRATEGIC PLAN AS THEY SEEK TO UNDERSTAND EARTH SEARCH FOR LIFE ELSEWHERE AND TO "DEVELOP TOOLS FOR DETECTING LIFE " ALL OF WHICH ARE HIGHLIGHTED UNDER OBJECTIVE 1.1. OUR WORK FALLS UNDER THE "BIOSIGNATURES AND LIFE ELSEWHERE" EMPHASIS OF THE EXOBIOLOGY PROGRAM AND WE AIM TO DEVELOP REMOTE SENSING TOOLS FOR DETECTING LIFE (WHICH IS A TOPIC ALSO HIGHLIGHTED BY THE EXOBIOLOGY PROGRAM). FINALLY OUR WORK ADDRESSES GOAL 5 OF NASA'S ASTROBIOLOGY STRATEGY ("IDENTIFYING EXPLORING AND CHARACTERIZING ENVIRONMENTS FOR HABITABILITY AND BIOSIGNATURES"). THROUGH OUR EMPHASIS ON UNDERSTANDING HOW FUTURE NASA MISSIONS MIGHT DETECT SIGNS OF LIFE FROM EARTH-LIKE EXOPLANETS WE ADDRESS PART IV OF GOAL 5 ("HOW CAN WE [. . . ] SEARCH FOR LIFE BEYOND THE SOLAR SYSTEM?") AS WELL AS KEY EXOPLANET RESEARCH QUESTIONS (E.G. "WHAT FUTURE TECHNOLOGIES MUST BE DEVELOPED IN ORDER TO BEST CHARACTERIZE EXOPLANETS FOR [. . . ] LIFE?").