Measurement of the directional distribution of incident particles in the Shuttle‐Mir mission orbit

The measurement of the directional distribution of incident particles was made by using the Real time Radiation Monitoring Device (RRMD)-III placed inside the Space Shuttle STS-84 cruised at an altitude of 400 km and an inclination angle of 51.6°, which are the same as the cruising orbit of the International Space Station (ISS). The directional distributions of incident particles were evaluated over the observed linear energy transfer (LET) range (1–100 keV/μm). The pitch angle distribution is also obtained using the geomagnetic model of IGRF-95. The result is roughly in good agreement with the distribution obtained by the VF1-MIN anisotropy model calculation within the present experimental errors, if the shielding distribution is assumed to be uniform.