I. Introduction
Detailed elemental spectra of cosmic rays in the energy range between 1012 and 1015 eV are necessary for testing theories about the origin and acceleration mechanism of the high-energy cosmic ray particles [1], [14], [2], [15], [3]. Existing measurements with limited statistics do not allow definite tests of theoretical models above about 1014 eV. Because of the small and rapidly decreasing flux with increasing energy the measurement of cosmic rays in the energy range requires long duration (longer than 600 m2 -sr-days) operation of instruments in space.