THIS UNSOLICITED PROPOSAL IS SUBMITTED TO NASA FOR SUPPORT SERVICES TO BE PROVIDED TO THE NEUTRON STAR INTERIOR COMPOSITION EXPLORER (NICER) DURING THE PERFORMANCE PERIOD OF 2019 JANUARY 1 TO SEPTEMBER 30. THIS TIME INTERVAL IS REFERRED TO AS THE NICER BRIDGE PHASE AND IT OCCURS BETWEEN THE NICER PRIME MISSION AND THE MISSION EXTENSION THAT IS SUBJECT TO FUNDING APPROVAL VIA THE NASA SENIOR REVIEW PROCESS (I.E. FY 2020 ONWARD). THIS PROPOSAL WOULD ALLOW THE CONTINUED CONTRIBUTIONS OF THE NICER TEAM AT THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY (MIT) TO PERFORM SUPPORT SERVICES RELATED TO THE NICER DETECTOR SYSTEM WHICH WAS BUILT AT MIT AND TO CONTRIBUTE SCIENTIFIC ANALYSES OF NICER DATA. FUNDING SUPPORT FOR THE MIT GROUP PRIOR TO THE BRIDGE PHASE COVERING NICER MISSION PHASES B THROUGH E WAS PROVIDED BY A NASA CONTRACT TO MIT (CONTRACT REFERENCE NNG14PJ13C) WHICH IS SET TO EXPIRE ON 2018 DECEMBER 31. NICER IS AN X-RAY ASTRONOMY CAMERA SYSTEM THAT HAS BEEN OPERATING ON THE INTERNATIONAL SPACE STATION (ISS) SINCE IT WAS LAUNCHED AND DEPLOYED IN 2017 JUNE (GENDREAU ET AL. 2016 PROCS. SPIE 9905E ID. 99051 H). THE NICER X-RAY TIMING INSTRUMENT (XTI) IS COMPOSED OF 56 IDENTICAL CAMERAS EACH CONSISTING OF AN X-RAY CONCENTRATOR OPTIC AND A CUSTOMIZED SI DRIFT DETECTOR POSITIONED IN THE CONCENTRATOR S FOCAL PLANE. THE OTHER PRIMARY COMPONENTS OF NICER ARE A CELESTIAL POINTING PLATFORM AND SEVEN ELECTRONICS BOXES EACH OF WHICH EXTRACTS EVENT MEASUREMENTS FROM THE SIGNAL LINES OF EIGHT DETECTORS. THE DETECTORS ARE KNOWN AS FOCAL PLANE MODULES (FPMS) AND THE ELECTRONIC BOXES ARE REFERRED TO AS MEASUREMENT&POWER UNITS (MPUS). BOTH THE FPMS AND MPUS WERE BUILT AND DELIVERED TO NASA BY THE TEAM AT MIT. THE PROPOSED SERVICES TO NICER DURING THE BRIDGE PHASE ARE ORGANIZED INTO TWO BROAD AREAS: (1) SUPPORT OF DETECTOR PERFORMANCE AND CALIBRATION AND (2) DATA ANALYSES&LEGACY SCIENCE. FURTHER DETAILS ARE PROVIDED BELOW INCLUDING A DESCRIPTIONS OF WORK TASKS ESTIMATES OF FTE SUPPORT NEEDED TO COMPLETE THESE TASKS AND A DETAILED BUDGET. MOST OF THE REQUESTED FUNDS WOULD PROVIDE PARTIAL SALARY SUPPORT OF MIT RESEARCH STAFF MEMBERS ENGAGED IN THE PROPOSED WORK AND ALL OF THESE STAFF MEMBERS HAVE PARTICIPATED IN THE HARDWARE BUILD NICER COMMISSIONING ACTIVITIES AND THE DATA ANALYSES DURING THE PRIME MISSION. THIS PROPOSAL ALSO CONTAINS A SUBCONTRACT FROM MIT TO ESPACE FOR THE COMPLETION AND DIAGNOSTIC APPLICATIONS OF AN INSTRUMENT SIMULATOR WITH WORK TO BE PERFORMED BY NOQSI SCIENTIFIC THE NICER PARTNER RESPONSIBLE FOR THE DESIGN OF THE MPU ELECTRONICS CIRCUITRY.