Project Grant 2621296

COLLABORATIVE RESEARCH: RAPID: TIME-CRITICAL GROUND-BASED OBSERVATIONS OF THE GEOCORONA DURING THE PRIMARY SCIENCE PHASE OF THE CARRUTHERS GEOCORONA OBSERVATORY -SURROUNDING EARTH IS THE EXOSPHERE, A VAST CLOUD OF HYDROGEN ATOMS THAT FORMS THE OUTERMOST EDGE OF OUR ATMOSPHERE AND EXTENDS TENS OF THOUSANDS OF KILOMETERS INTO SPACE. THIS REGION PLAYS IMPORTANT YET POORLY UNDERSTOOD ROLES IN ATMOSPHERE NEAR-SPACE INTERACTIONS, INCLUDING HOW EARTH RECOVERS FROM GEOMAGNETIC STORMS ? SOLAR-DRIVEN DISTURBANCES THAT CAN DISRUPT SATELLITE COMMUNICATIONS, GPS NAVIGATION, AND POWER GRIDS. THE PROJECT SERVES THE NATIONAL INTEREST BY IMPROVING SPACE WEATHER PREDICTION AND RESILIENCE, HELPING TO PROTECT SATELLITES, CRITICAL INFRASTRUCTURE AND ASTRONAUTS. IT ADVANCES FUNDAMENTAL UNDERSTANDING OF HOW EARTH?S ATMOSPHERE INTERACTS WITH THE SPACE ENVIRONMENT, WITH BROADER IMPLICATIONS FOR ATMOSPHERIC ESCAPE AND PLANETARY HABITABILITY. THE WORK ALIGNS WITH NATIONAL PRIORITIES FOR DISTRIBUTED GROUND-BASED OBSERVING SYSTEMS AND SUPPORTS STUDENT TRAINING THROUGH A MULTI-INSTITUTIONAL COLLABORATION WITH OPENLY ACCESSIBLE DATA PRODUCTS. THIS PROJECT LEVERAGES A RARE, TIME-SENSITIVE OPPORTUNITY CREATED BY RECENT START OF SCIENCE OPERATIONS FOR NASA?S CARRUTHERS GEOCORONA OBSERVATORY, COINCIDING WITH THE DECLINE FROM THE PEAK OF SOLAR CYCLE 25. DURING THE PERIOD OF ELEVATED SOLAR ACTIVITY, OVERLAPPING SPACE- AND GROUND-BASED OBSERVATIONS OF EARTH?S EXTENDED HYDROGEN ATMOSPHERE ARE PLANNED. BECAUSE SPACECRAFT CANNOT FULLY OBSERVE THE NIGHTSIDE OF EARTH, A DISTRIBUTED NETWORK OF GROUND-BASED OBSERVATORIES ACROSS NORTH AND SOUTH AMERICA WOULD BE USED TO FILL THESE GAPS. TOGETHER, THESE MEASUREMENTS WILL PRODUCE A COORDINATED, THREE-DIMENSIONAL VIEW OF THE EXOSPHERE NOT ACHIEVABLE BY EXISTING OBSERVATIONS ALONE AND REVEAL ITS STORM-TIME RESPONSE. THIS PROJECT INVESTIGATES THE STRUCTURE AND DYNAMICS OF EARTH?S HYDROGEN EXOSPHERE, WHERE CHARGE EXCHANGE WITH MAGNETOSPHERIC HYDROGEN AND OXYGEN IONS PLAYS A CENTRAL ROLE IN GEOMAGNETIC STORM RECOVERY. THE PROJECT ENABLES NEW CONSTRAINTS ON EXOSPHERIC HYDROGEN DENSITY BY COMBINING LYMAN-ALPHA OBSERVATIONS FROM THE CARRUTHERS GEOCORONA OBSERVATORY WITH NEAR COINCIDENT GROUND-BASED MEASUREMENTS OF BALMER-ALPHA AND BALMER-BETA EMISSION OBTAINED USING FABRY?PEROT INTERFEROMETERS AND NARROW-BAND PHOTOMETERS. THIS EFFORT REPRESENTS A UNIQUE OPPORTUNITY TO OBTAIN COMPLEMENTARY MEASUREMENTS THAT ARE NOT ACHIEVABLE BY THE SPACE-BASED MISSION ALONE. THIS AWARD REFLECTS NSF'S STATUTORY MISSION AND HAS BEEN DEEMED WORTHY OF SUPPORT THROUGH EVALUATION USING THE FOUNDATION'S INTELLECTUAL MERIT AND BROADER IMPACTS REVIEW CRITERIA.- SUBAWARDS ARE NOT PLANNED FOR THIS AWARD.