Solar particle events observed on MIR station.

Radiation impact of the SPEs on board the MIR space station and in the interplanetary space is discussed in the report. The data of the on-board radiation dosimeter R-16 were used to measure the SPE absorbed doses. Some of SPEs (such as September-October 1989 series of very large SPEs) were measured in detail by Liulin active high sensitive dosimetric instrument installed on board MIR station. MIR station orbit measurements of the absorbed doses are compared with the interplanetary absorbed doses from SPEs estimated by the data obtained by the METEOR satellite spectrometer. The equivalent dose beyond the magnetosphere resulting from the September 29, 1989 solar flare in a spacecraft module with ordinary shielding thickness (approximately 10 g/cm2 of Al) is far higher than the maximum permissible dose of acute single exposure (50 cSv) and comparable with the maximum permissible dose of 2 year mission (118 cSv). Such large SPEs are a serious hazard in interplanetary missions and call forth of special administrative countermeasures.