T he primary objective of the experiment was to provide dosimetric data on the penetrating ionizing cosmic radiation as environmental background information for those life science microgravity experiments on Biorack which might also be sensitive to this spaceflight factor. The analysis and interpretation of the experimental findings from such experiments must rely on these measurements, since calculations of the radiation environment inside space vehicles still have error margins too large to be useful for quantitative analysis. This holds especially for the densely ionizing component of heavy ions and nuclear disintegration stars with their potentially unique radiobiological effectiveness [i, 2]. The complex particle and energy spectra of the cosmic radiation field render any dosimetry with a single physical detector system inapt. Therefore three detector systems, LiF-thermoluminescence dosimeters (TLD), nuclear emulsions, and plastic nuclear track detectors, were combined for the registration of the integral absorbed dose from the sparsely ionizing "background" radiation of electrons, protons and electromagnetic radiation, of nuclear disintegration stars, and of heavy-ion tracks, respectively. A secondary objective was to enlarge the empirical data on the radiation field inside space vehicles in nearearth orbits as a check for calculated predictions.