Description of the payload

The Gamma-RAy Polarimeter Experiment (GRAPE) is a Compton polarimeter designed to measure the polarization of astronomical sources in the soft gamma-ray band (50 - 500 keV) from a high-altitude balloon platform. Although designed primarily for studies of gamma-ray bursts over the entire sky, the instrument can also be combined with a collimator for pointed observations.

Details of the balloon flight and scientific outcome

Launch site: Scientific Flight Balloon Facility, Fort Sumner, (NM), US  
Balloon launched by: Columbia Scientific Balloon Facility (CSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon  
Flight identification number: 655N

External references and bibliographical sources

Images of the mission