ROUGHLY 50% OF SUN-LIKE STARS BELONG TO MULTI-STAR SYSTEMS AND THE NEAREST EXOPLANET TO EARTH RESIDES IN THE EXTENDED TRIPLE STAR SYSTEM OF ALPHA AND PROXIMA CENTAURI. THUS UNDERSTANDING THE DYNAMICAL HISTORIES OF PLANETS BELONGING MULTI-STAR SYSTEMS IS CRITICAL TO INTERPRETING EXOPLANET OBSERVATIONS. SUCH SYSTEMS CANNOT BE MODELED IN ISOLATION FOR THEIR STELLAR DYNAMICS (AND BY EXTENSION PLANETARY DYNAMICS) ARE STRONGLY INFLUENCED BY EXTERNAL PERTURBATIONS FROM THE MILKY WAY. THESE PERTURBATIONS OFTEN EXCITE THE STELLAR COMPANIONS' ORBITS UNTIL THEY DESTABILIZE PLANETARY SYSTEMS. YET DYNAMICAL MODELING OF PLANETARY SYSTEMS IN THEIR LARGER ENVIRONMENTS IS CHALLENGING BECAUSE A COMPLEX LARGER-SCALE POTENTIAL MUST BE PROPERLY HANDLED IN CONCERT WITH THE EFFICIENT ACCURATE INTEGRATION OF NEAR-KEPLERIAN MOTION OVER MUCH SMALLER SCALES. WE HAVE RECENTLY EXTENDED THE PLANETARY SIMULATION CODE MERCURY TO DO JUST THIS GIVING US UNPRECEDENTED OPPORTUNITIES TO STUDY HOW PLANETARY SYSTEMS ARE INFLUENCED BY THEIR LARGER ENVIRONMENTS. USING THIS NEW TOOL WE WILL 1) REASSESS THE DYNAMICAL HISTORY OF ALPHA CENTAURI AND ITS POTENTIAL PLANETS 2) UNDERSTAND HOW DESTABILIZED PLANETARY SYSTEMS DIFFER FROM UNALTERED ONES WITHIN ALPHA CENTAURI AND 3) DETERMINE WHETHER STELLAR BIRTH CLUSTERS DRIVE BINARY STARS INTO DISRUPTING ONE ANOTHER'S PLANETARY SYSTEMS. THIS WORK IS HIGHLY ALIGNED WITH THE STATED GOALS OF NASA EXOPLANET RESEARCH PROGRAM AS EACH OF OUR PROPOSED TASKS PROMISES TO "IMPROVE UNDERSTANDING OF THE ORIGINS OF EXOPLANETARY SYSTEMS " AND OUR WORK PROMISES TO SIGNIFICANTLY IMPACT THE FIELD OF EXOPLANETS OVER THE NEXT 5 YEARS.