GP-B Gravity Probe B Type Orbiter Launch April 20, 2004 Location Earth orbit Objective Measure two key predictions of Einstein's general theory of relativity Learn more about GP-B Latest News More Gravity Probe B (GP-B) News Article3 Min ReadIntersection of Art and Einstein: Barron Storey’s Gravity Probe B Illustrations Keep Exploring Discover More from Earth Science Explore Earth Science Earth Science at Work NASA Earth Science helps Americans respond to challenges and societal needs — such as wildland fires, hurricanes, and water supplies… Earth Science Missions In order to study the Earth as a whole system and understand how it is changing, NASA develops and supports… Earth Science Data Open access to NASA’s archive of Earth science data