Abstract:The project ALTEA-shield/survey is part of an European Space Agency (ESA) -ILSRA (International Life Science Research Announcement) program and provides a detailed study of the International Space Station (ISS) (USLab and partly Columbus) radiation environment. The experiment spans over 2 years, from September 20, 2010 to September 30, 2012, for a total of about 1.5 years of effective measurements. The ALTEA detector system measures all heavy ions above helium and, to a limited extent, hydrogen and helium (res… Show more
“…The fields of view of the detector are fully covered by the above and below drawers/experiments. The spectra of the Z data in this position (Narici et al 2015a) shows higher (than in the other positions) flux for all LET values above carbon, and lower below. The higher dose rate in Z shown in Figure 11 is therefore probably an effect of a different radiation quality due to a significant amount of higher LET ions possibly generated by the interactions of the primary radiation with the material closely surrounding ALTEA.…”
Section: Discussionmentioning
confidence: 63%
“…Also in this last case the dose rate values are almost coincident while the ALTEA X fluxes are consistently higher than the ALTEA Z fluxes. This can be explained (Narici et al 2015a) taking into account the different amount of shielding: in P3, in X, there is much more shielding than in Z. Therefore, in X there is more fragmentation (higher flux) and consequently a lower dose per ion providing grounds for the similar values in dose rates.…”
Section: Discussionmentioning
confidence: 99%
“…Our procedure takes this into account. If explicitly considering the Earth shielding the result would indeed not change: for example for the Z-directed telescopes we would have used a single ended GF (which is ½ of the double ended), assuming all particles coming from above, then integrate only over 2p, producing the same result (Narici et al 2015a). …”
The solar system exploration by humans requires to successfully deal with the radiation exposition issue. The scientific aspect of this issue is twofold: knowing the radiation environment the astronauts are going to face and linking radiation exposure to health risks. Here we focus on the first issue. It is generally agreed that the final tool to describe the radiation environment in a space habitat will be a model featuring the needed amount of details to perform a meaningful risk assessment. The model should also take into account the shield changes due to the movement of materials inside the habitat, which in turn produce changes in the radiation environment. This model will have to undergo a final validation with a radiation field of similar complexity. The International Space Station (ISS) is a space habitat that features a radiation environment inside which is similar to what will be found in habitats in deep space, if we use measurements acquired only during high latitude passages (where the effects of the Earth magnetic field are reduced). Active detectors, providing time information, that can easily select data from different orbital sections, are the ones best fulfilling the requirements for these kinds of measurements. The exploitation of the radiation measurements performed in the ISS by all the available instruments is therefore mandatory to provide the largest possible database to the scientific community, to be merged with detailed Computer Aided Design (CAD) models, in the quest for a full model validation. While some efforts in comparing results from multiple active detectors have been attempted, a thorough study of a procedure to merge data in a single data matrix in order to provide the best validation set for radiation environment models has never been attempted. The aim of this paper is to provide such a procedure, to apply it to two of the most performing active detector systems in the ISS: the Anomalous Long Term Effects in Astronauts (ALTEA) instrument and the DOSimetry TELescope (DOSTEL) detectors, applied in the frame of the DOSIS and DOSIS 3D project onboard the ISS and to present combined results exploiting the features of each of the two apparatuses.
“…The fields of view of the detector are fully covered by the above and below drawers/experiments. The spectra of the Z data in this position (Narici et al 2015a) shows higher (than in the other positions) flux for all LET values above carbon, and lower below. The higher dose rate in Z shown in Figure 11 is therefore probably an effect of a different radiation quality due to a significant amount of higher LET ions possibly generated by the interactions of the primary radiation with the material closely surrounding ALTEA.…”
Section: Discussionmentioning
confidence: 63%
“…Also in this last case the dose rate values are almost coincident while the ALTEA X fluxes are consistently higher than the ALTEA Z fluxes. This can be explained (Narici et al 2015a) taking into account the different amount of shielding: in P3, in X, there is much more shielding than in Z. Therefore, in X there is more fragmentation (higher flux) and consequently a lower dose per ion providing grounds for the similar values in dose rates.…”
Section: Discussionmentioning
confidence: 99%
“…Our procedure takes this into account. If explicitly considering the Earth shielding the result would indeed not change: for example for the Z-directed telescopes we would have used a single ended GF (which is ½ of the double ended), assuming all particles coming from above, then integrate only over 2p, producing the same result (Narici et al 2015a). …”
The solar system exploration by humans requires to successfully deal with the radiation exposition issue. The scientific aspect of this issue is twofold: knowing the radiation environment the astronauts are going to face and linking radiation exposure to health risks. Here we focus on the first issue. It is generally agreed that the final tool to describe the radiation environment in a space habitat will be a model featuring the needed amount of details to perform a meaningful risk assessment. The model should also take into account the shield changes due to the movement of materials inside the habitat, which in turn produce changes in the radiation environment. This model will have to undergo a final validation with a radiation field of similar complexity. The International Space Station (ISS) is a space habitat that features a radiation environment inside which is similar to what will be found in habitats in deep space, if we use measurements acquired only during high latitude passages (where the effects of the Earth magnetic field are reduced). Active detectors, providing time information, that can easily select data from different orbital sections, are the ones best fulfilling the requirements for these kinds of measurements. The exploitation of the radiation measurements performed in the ISS by all the available instruments is therefore mandatory to provide the largest possible database to the scientific community, to be merged with detailed Computer Aided Design (CAD) models, in the quest for a full model validation. While some efforts in comparing results from multiple active detectors have been attempted, a thorough study of a procedure to merge data in a single data matrix in order to provide the best validation set for radiation environment models has never been attempted. The aim of this paper is to provide such a procedure, to apply it to two of the most performing active detector systems in the ISS: the Anomalous Long Term Effects in Astronauts (ALTEA) instrument and the DOSimetry TELescope (DOSTEL) detectors, applied in the frame of the DOSIS and DOSIS 3D project onboard the ISS and to present combined results exploiting the features of each of the two apparatuses.
“…2). In this configuration the SDUs were oriented along the ISS Z axis (ISS coordinate: Nadir - Zenith), which is likely the least shielded one 2, 12 .Figure 2Position of the ALTEA-shield system. The ALTEA system is shown in its measurement location inserted in Express Rack 3 in the Columbus module.
…”
Section: Resultsmentioning
confidence: 99%
“…Even if within the protection of the Earth’s magnetic field, the spectrum of the radiation environment inside the ISS at high latitudes is the closest available replica of the outer space radiation spectrum 2 .…”
Passive radiation shielding is a mandatory element in the design of an integrated solution to mitigate the effects of radiation during long deep space voyages for human exploration. Understanding and exploiting the characteristics of materials suitable for radiation shielding in space flights is, therefore, of primary importance. We present here the results of the first space-test on Kevlar and Polyethylene radiation shielding capabilities including direct measurements of the background baseline (no shield). Measurements are performed on-board of the International Space Station (Columbus modulus) during the ALTEA-shield ESA sponsored program. For the first time the shielding capability of such materials has been tested in a radiation environment similar to the deep-space one, thanks to the feature of the ALTEA system, which allows to select only high latitude orbital tracts of the International Space Station. Polyethylene is widely used for radiation shielding in space and therefore it is an excellent benchmark material to be used in comparative investigations. In this work we show that Kevlar has radiation shielding performances comparable to the Polyethylene ones, reaching a dose rate reduction of 32 ± 2% and a dose equivalent rate reduction of 55 ± 4% (for a shield of 10 g/cm2).
The radiation risk radiometer‐dosimeter (R3D)‐R2 solid‐state detector performed radiation measurements at the European Space Agency EXPOSE‐R2 platform outside of the Russian “Zvezda” module at the International Space Station (ISS) from 24 October 2014 to 11 January 2016. The ISS orbital parameters were average altitude of 415 km and 51.6° inclination. We developed special software and used experimentally obtained formulas to determine the radiation flux‐to‐dose ratio from the R3DR2 Liulin‐type deposited‐energy spectrometer. We provide for the first time simultaneous, long‐term estimates of radiation dose external to the ISS for four source categories: (i) galactic cosmic ray particles and their secondary products; (ii) protons in the South Atlantic Anomaly region of the inner radiation belt (IRB); (iii) relativistic electrons and/or bremsstrahlung in the outer radiation belt (ORB); and (iv) solar energetic particle (SEP) events. The latter category is new in this study. Additionally, in this study, secondary particles (SP) resulting from energetic particle interaction with the detector and nearby materials are identified. These are observed continuously at high latitudes. The detected SPs are identified using the same sorting requirements as SEP protons. The IRB protons provide the highest consistent hourly dose, while the ORB electrons and SEPs provide the most extreme hourly doses. SEPs were observed 11 times during the study interval. The R3DR2 data support calculation of average equivalent doses. The 30 day and 1 year average equivalent doses are much smaller than the skin and eyes doses recommendations by the National Council on Radiation Protection (Report 132), which provides radiation protection guidance for Low Earth Orbit.
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