Spectrometric characteristics of High Pressure Xenon (HPXe) gamma-ray spectrometer "Ksenia" was studied during operation of this instrument onboard the orbital station "MIR". The energy resolution of this spectrometer is 3.5*0.5% at Ey = 511 keV and stable during period from May1990 till May 1997. The position of 511 keV gamma line is also stable (k1 channel or +4keV). The total number of trapped in Radiation Belt particles passed through the detector is 5~1 0~. Neutrons of atmospheric albino is 2.10''.No activated gamma-lines were found during the flight.After intensive activation (fluence about 1.5.10'' neutrons) of cylindrical HPXe spectrometer with volume of Xe about 6 litters at the laboratory few activated gamma-lines were registrated: Ey=164 keV, TIl2=11.92 from 131Xem; Ey=236 keV, T112=8.89 days from 129Xem and Ey=847 keV, TIl2=2.56 hours from 56Mn.The intensity of these lines is not large so it is possible to operate HPXe spectrometers even after intensive irradiation.