Several small disks of cellulose nitrate plastic were included as a part of a passive dosimetry package aboard the Gemini VI spacecraft for the purpose of recording the heavy component of the solar and the primary cosmic radiation. An average of 230 tracks/cm2 per day was observed. Of these about 70 tracks/cm2 were background alpha particle tracks produced by natural radioactivity. About 159 tracks/cm2-day were due to stopping alpha particles of solar and galactic origin; a few heavy recoil ion tracks were also observed. About one track/cm2-day was judged to be due to the heavy primary cosmic ray particles. Relativistic iron nuclei apparently do not produce tracks in this sensitivity of cellulose nitrate. It appears that by stacking sheets of cellulose nitrate into sandwich configurations it is possible to have a simple and direct means of measuring the integrated flux and energy spectra of solar alpha particles inside the manned spacecraft.