Measuring Newton’s Gravitational Constant from Space with LISA Pathfinder

ORAL

Abstract

The value of Newton’s Gravitational Constant (“Big G”) remains uncertain beyond the third significant digit; numerous experiments have produced results with non-overlapping confidence intervals. Identifying and controlling for systematic effects in Big G experiments is a significant challenge. The relative weakness of the gravitational force allows a myriad of influences to distort experimental results. In this work, we make a first attempt at measuring Big G with LISA Pathfinder (LPF) flight data. All Big G measurements to date have been performed from Earth's surface; a measurement from space presents the possibility to identify systematic errors inherent to terrestrial measurement. LPF has demonstrated the ability to measure differential acceleration between two test masses to femto-scale precision. This level of precision allows for a meaningful measurement of the change in differential acceleration between the test masses due to propellant expenditure. In addition to this direct measurement, mass flow sensor data and a gravitational finite element model of the LPF fuel system are used to develop a mathematical model predicting this propellant effect. A Markov Chain Monte Carlo method then fits this model to the observed data to produce probability distributions of the model

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Authors

  • Mengyu Wang

    Iowa State University

  • Swapan Chattopadhyay

    Gravitational Astrophysics Lab, NASA Goddard Space Flight Center, Northern Illinois University and Argonne National Laboratory, Northern Illinois University, None, Monmouth College, IL, University of California Santa Cruz, Southern Illinois University Carbondale, Argonne National Laboratory, University of Iowa, Sinop University, Bingol University, Univ of Northern Iowa, University of California, Riverside, University of Northern Iowa, University of Wisconsin, Fairfield University, North Central College

  • Swapan Chattopadhyay

    Gravitational Astrophysics Lab, NASA Goddard Space Flight Center, Northern Illinois University and Argonne National Laboratory, Northern Illinois University, None, Monmouth College, IL, University of California Santa Cruz, Southern Illinois University Carbondale, Argonne National Laboratory, University of Iowa, Sinop University, Bingol University, Univ of Northern Iowa, University of California, Riverside, University of Northern Iowa, University of Wisconsin, Fairfield University, North Central College