Cosmic ray studies in the first Space Shuttle - Spacelab

Recent studies in spacecrafts in interplanetary and near-earth space revealed the presence of low energy cosmic ray heavy ions of unknown origin with strikingly different properties as compared to high energy cosmic rays. The measurements in the Skylab in the near-earth indicated that these heavy ions are probably in partly ionised states. In order to obtain new information on the origin of this anomalous component of cosmic rays, an experiment is under preparation for the first Space Shuttle, Spacelab Mission to study the ionisation states of low energy heavy ions of cosmic rays, their abundances, intensities and energy spectra. In this experiment, the arrival time and arrival direction of each of the ions of C to Fe in 5-100 MeV/N energy interval and their other properties are determined and from these, lower bounds of their magnetic rigidities are obtained. By combining these data with the momemtum of the particles, their ionisation states are determined. In case of a solar event, the ionisation states of the solar particles are also measured. The design, fabrication, assembly and testing of the instrument are being done in India, following which it will be integrated with the First Spacelab for one week's space mission with Space Shuttle. A brief description of the experiment is presented. (auth.)