Satellite experiments have found evidence of positrons (as well as a few antiprotons) in primary cosmic rays, amounting to less than 1% of the particles in primary cosmic rays. However, the fraction of positrons in cosmic rays has been measured more recently with improved accuracy, especially at much higher energy levels, and the fraction of positrons has been seen to be greater in these higher energy cosmic rays.
Satellite experiments have found evidence of positrons (as well as a few antiprotons) in primary cosmic rays amounting to less than 1% of the particles in primary cosmic rays However the fraction of positrons in cosmic rays has been measured more recently with improved accuracy especially at much higher energy levels and the fraction of positrons has been seen to be greater in these higher energy cosmic rays