Precision spheres for the Gravity Probe B experiment. (17th November 2015)

• Record Type: Journal Article
• Authors: Marcelja, F; DeBra, D B; Keiser, G M; Turneaure, J P
• Is Part Of: Classical and quantum gravity. Volume 32:Number 22(2015:Nov.)
• Publication Date: 2015-11-17
• Subjects: Gravity Probe B -- precision spheres -- electrostatically supported gyroscopes -- sphericity measurements -- density homogeneity -- fused-quartz spheres -- single-crystal silicon spheres; Quantum gravity -- Periodicals; Gravitation -- Periodicals; Relativity (Physics) -- Periodicals; Space and time -- Periodicals; Periodicals; 521.1
• DOI: 10.1088/0264-9381/32/22/224007
• Languages: English
• ISSNs: 0264-9381

Abstract

Abstract: Spherical gyroscope rotors for a fundamental experiment to test two predictions of General Relativity Theory, geodetic precession and frame dragging, were manufactured out of fused quartz and single-crystal silicon. These rotors required a mass unbalance and asphericity of less than 25 nm (1 μ in), a fractional difference in the moments of inertia of less than 10 −5, and a diameter within 0.5 μ m (20 μ in) of a standard sphere with a diameter of 37.996 mm (1.4959 in). We describe the manufacturing process and the associated metrology.