Published online by Cambridge University Press: 14 August 2015
A cosmic ray detector, sensitive to γ-Rays with energies greater than 500 MeV is being flown on board the OGO-5 satellite. The spacecraft was launched into a highly eccentric orbit, apogee 145000 km, on March 4, 1968. γ-Ray observations are restricted to altitudes higher than 80000 km, thereby excluding interference from the radiation belts and reducing the influence from the earth albedo flux. A description of the instrument is published in the literature (Rogowski et al., 1969).