THE GRAVITY RECOVERY AND CLIMATE EXPERIMENT (GRACE) MISSION HAS PROVIDED A WEALTH OF INFORMATION FOR ADVANCING THE OBJECTIVES OF NASA S SOLID EARTH SCIENCE PROGRAM. GRACE AND THE UPCOMING GRACE FOLLOW-ON MISSION PROVIDE ONE OF THE ONLY COMPREHENSIVE MEASUREMENTS OF HOW WATER AND ICE MASS IS EXCHANGED BETWEEN THE LAND AND THE OCEANS. MEASURING THESE EXCHANGES IS CRITICAL FOR UNDERSTANDING THE RESPONSE OF THE SOLID EARTH TO THE MASS LOADING AND UNLOADING WHICH IS IMPORTANT FOR SEA LEVEL SCIENCE AND OTHER APPLICATIONS. LAND WATER STORAGE CHANGES ARE ONE OF THE PRINCIPAL DRIVERS OF INTERANNUAL VARIABILITY IN GLOBAL MEAN SEA LEVEL AND ICE MASS CHANGES DRIVE THE LONG-TERM TRENDS IN SEA LEVEL CHANGE. AS THE LOADING ON THE SOLID EARTH CHANGES THIS CAUSES VERTICAL CRUSTAL MOTION (AS OBSERVED BY GNSS RECEIVERS) WHICH IMPACTS RELATIVE SEA LEVEL CHANGES AS OBSERVED BY TIDE GAUGES. AS SUCH UNDERSTANDING THE MOTION OF THE SOLID EARTH IS A CRITICAL COMPONENT OF SEA LEVEL CHANGE STUDIES. GRACE HAS ALSO BEEN USED TO UNDERSTAND THE LINK BETWEEN WATER STORAGE/LOADING CHANGES AND EARTHQUAKE SEISMICITY UNDERSTAND THE LINKS BETWEEN WATER MASS CHANGES AND EARTH ROTATION VARIATIONS AND PROVIDE IMPROVEMENTS TO THE TERRESTRIAL REFERENCE FRAME. THE END RESULT OF THIS RESEARCH WILL BE AN ASSESSMENT OF THE NEW AND IMPROVED SOLID EARTH SCIENCE THAT COULD BE ACHIEVED VIA MULTISATELLITE GRACE-TYPE CONSTELLATIONS AND RECOMMENDATIONS ON WHAT ORBITS SHOULD BE USED FOR THESE SATELLITES. IN ADDITION WE WILL ALSO MAKE RECOMMENDATIONS ON THE MEASUREMENT ACCURACY REQUIREMENTS (RANGING SYSTEM ACCELEROMETER ETC.) NEEDED FOR SUCH A CONSTELLATION.