Novel methods to measure the gravitational constant in space
Mendes, L.; Russano, G.; Nofrarias, M.; Armano, M.; Audley, H.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Castelli, E.; Cavalleri, A.; Cesarini, A.; Cruise, A. M.; Danzmann, K.; de Deus Silva, M.; Diepholz, I.; Dixon, G.; Dolesi, R.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E. D.; Freschi, M.; Gesa, L.; Giardini, D.; Gibert, F.; Giusteri, R.; Grimani, C.; Grzymisch, J.; Harrison, I.; Hartig, M. -S.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hoyland, D.; Hueller, M.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C. J.; Liu, L.; Lobo, J. A.; López-Zaragoza, J. P.; Maarschalkerweerd, R.; Mance, D.; Martín, V.; Martin-Polo, L.; Martin-Porqueras, F.; Martino, J.; McNamara, P. W.; Mendes, J.; Meshksar, N.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Ramos-Castro, J.; Reiche, J.; Rivas, F.; Robertson, D. I.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J. I.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Wass, P. J.; Weber, W. J.; Wissel, L.; Wittchen, A.; Zweifel, P.; Trenkel, C.; LISA Pathfinder Collaboration
Netherlands, Germany, France, Italy, United Kingdom, Spain, Switzerland, United States
Abstract
We present two novel methods, tested by LISA Pathfinder, to measure the gravitational constant G for the first time in space. Experiment 1 uses electrostatic suspension forces to measure a change in acceleration of a test mass due to a displaced source mass. Experiment 2 measures a change in relative acceleration between two test masses due to a slowly varying fuel tank mass. Experiment 1 gave a value of G =6.71 ±0.42 (×10-11) m3 s-2 kg-1 and experiment 2 gave 6.15 ±0.35 (×10-11) m3 s-2 kg-1 , both consistent with each other to 1 σ and with the CODATA 2014 recommended value of 6.67408 ±0.00031 (×10-11) m3 s-2 kg-1 to 2 σ . We outline several ideas to improve the results for a future experiment, and we suggest that a measurement in space would isolate many terrestrial issues that could be responsible for the inconsistencies between recent measurements.