Status of development of the Quantum Gravity Gradiometer Pathfinder Concept

Quantum Gravity Gradiometry (QGG), based on atom interferometric inertial sensing, offers the promise of accurate, high-resolution mass-change estimation from stable, well-calibrated, µE precision measurement of gravity gradients from orbit. Much of the technology for measurement and utilization of µE precision gradiometry, using a so-called "science grade instrument" (SGI) targeting ambitious next-generation Earth science community needs for mass change measurements, remains yet to be developed. However, current start of the art of atom interferometry allows testing and validation of key ideas behind the QGG concept in low-precision spaceflight experiments, as essential pathfinding to the SGI. We present the current status of the JPL-led QGG Pathfinder Concept Study from the viewpoint of the underlying science motivation of the SGI concept, the lessons to be learned from measurements drawn from a lower precision QGG pathfinder instrument, and the related mission design and concept of operations for the Pathfinder study.