Cosmic ray detection in space

Abstract Cosmic rays are energetic particles composed primarily of protons and helium nuclei but including, with varying abundances, all atomic nuclei species, electrons and even antiparticles. They originate from sources that, save for the highest energies, are located in the Galaxy. After more than one century from their discovery and except for a clear contribution, particularly important at energies lower than a few GeV, from our Sun the origin of cosmic rays is still an open question. Supernovae explosion, pulsars, relativistic jets, active galactic nuclei, have been proposed as sources of cosmic rays although unambiguous evidences have still to be found. The study of the cosmic radiation have been approached, indirectly, with instrumentation located on ground and, directly, with apparatus placed on stratospheric balloons and satellites. The last decades have seen a flourishing of new techniques applied to space science with satellite-borne experiments taking center stage in the unveiling of the properties of the cosmic radiation.