Method for the prediction of the effective dose equivalent to the crew of the International Space Station

This paper describes a methodology for assessing the pre-mission exposure of space crew aboard the International Space Station (ISS) in terms of an effective dose equivalent. In this approach, the PHITS Monte Carlo code was used to assess the particle transport of galactic cosmic radiation (GCR) and trapped radiation for solar maximum and minimum conditions through an aluminum shield thickness. From these predicted spectra, and using fluence-to-dose conversion factors, a scaling ratio of the effective dose equivalent rate to the ICRU ambient dose equivalent rate at a 10 mm depth was determined. Only contributions from secondary neutrons, protons, and alpha particles were considered in this analysis.     

A model for predicting the radiation exposure for mission planning aboard the international space station

The International Space Station Cosmic Radiation Exposure Model (ISSCREM) has been developed as a possible tool for use in radiation mission planning as based on operational data collected with a tissue equivalent proportional counter (TEPC) aboard the ISS since 2000. It is able to reproduce the observed trapped radiation and galactic cosmic radiation (GCR) contributions to the total dose equivalent to within ±20% and ±10%, respectively, as would be measured by the onboard TEPC at the Zvezda Service Module panel 327 (SM-327). Furthermore, when these contributions are combined, the total dose equivalent that would be measured at this location is estimated to within ±10%. The models incorporated into ISSCREM correlate the GCR dose equivalent rate to the cutoff rigidity magnetic shielding parameter and the trapped radiation dose equivalent rate to atmospheric density inside the South Atlantic Anomaly. The GCR dose equivalent rate is found to vary minimally with altitude and TEPC module location however, due to the statistics and data available, the trapped radiation model could only be developed for the TEPC located at SM-327. Evidence of the variation in trapped radiation dose with detector orientation and the East–West asymmetry were observed at this location.     

The role of cross-cultural factors in long-duration international space missions: lessons from the SFINCSS-99 study

The role of cross-cultural factors in long-duration international space missions was examined during an isolation study that simulated many of the conditions aboard the International Space Station. Methods: Interactions involving two heterogeneous crews and one homogeneous crew staying in isolation from 110 to 240 days were studied. Data consisted of post-isolation interviews with crewmembers, ground support personnel and management, observational data, and public statements by crewmembers. Data was analyzed using the techniques of linguistic anthropology and ethnography. Results: Sub-cultural (organizational and professional) differences played a larger role than national differences in causing misunderstandings in this study. Conversely, some misunderstandings and conflicts were escalated by participants falsely assuming cultural differences or similarities. Comparison between the two heterogeneous crews showed the importance of training, personality factors, and commander and language skills in preventing and alleviating cultural misunderstandings. Conclusion: The study revealed a number of ways that cultural differences, real as well as assumed, can play a role and interact with other, non-cultural, factors in causing and/or precipitating conflict situations. It is postulated that such difficulties can be avoided by selecting culturally adaptive crewmembers and by cross-cultural and language training. Also the crew composition and role of commander were found to be important in mitigating conflict situations.