  The AMS-02 detector will operate for at least 3 years on the International
Space Station, measuring cosmic ray spectra at about 400 km above sea level
over a wide range of geomagnetic latitude.
  The proximity focusing ring imaging \v{C}erenkov counter of AMS-02 will
measure the particle velocity $\beta$ with $\approx 0.1%$ uncertainty, making
possible to discriminate Beryllium isotopes up to about 15 GeV/nucl. In
addition its charge measurement will allow to study the elemental composition
of cosmic rays up to Iron. A prototype of the RICH detector was tested with
cosmic rays and on a ion beam accelerated by SPS, at CERN (October 2002).
