Test of Relativistic Gravitation with a Space-Borne Hydrogen Maser

Abstract

The results of a test of general relativity with use of a hydrogen-maser frequency standard in a spacecraft launched nearly vertically upward to 10 000 km are reported. The agreement of the observed relativistic frequency shift with prediction is at the 70\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$ level.