Because the National Aeronautics and Space Administration (NASA) decided to extend the mission lifetime of the Gamma Ray Observatory (GRO), the agency is starting a guest investigator program for GRO, to get the most out of the onboard instruments.
GRO is a satellite that will be launched from the space shuttle in a nominal 450 km circular orbit with an inclination of 28.5°. Deployment is scheduled for November 1990. The aim is to obtain observations of astronomical gamma rays from 50 keV to 30 GeV for such studies as formation of the elements, particle acceleration in the Sun, stars and steller systems, origin of the cosmic diffuse background, and the origin and evolution of the universe itself. After 20 days of checkout, GRO will spend 15 months doing an all-sky survey before the 12-month Phase 1 Guest Investigator Program begins.