ABSTRACT
Distribution of neutron equivalent dose both inside and outside the spherical phantom (experiment Matryeshka-R) was determined with the help of dedicated research equipment "Bubble-dosimeter". Equipment is built up from an automatic bubbles counter and 8 bubble detectors of neutrons with energy ranging from approximately 200 keV to 15 MeV. Measurements inside the ISS were made in several 7-day sessions in the period from April 2006 till October 2007 (ISS increments 13-15). According to the bubble detectors on the outside of the phantom, ambient neutron dose H*(10) was equal to 0.1 mSv/d or approximately 20% of the dose from charged particles inside the ISS. In the tissue-equivalent phantom, neutron dose was 1.2 +/- 0.2 times less as compared with the phantom surface which characterized the degree of dose attenuation in cosmonaut's body.
Subject(s)
Cosmic Radiation , Neutrons , Radiation Dosage , Radiation Monitoring/instrumentation , Spacecraft , Equipment Design , HumansABSTRACT
Russian space experiment "Matryeshka-R" was conducted in 2004-2005 to study dose distribution in the body of anthropomorphous phantom inserted in a spacesuit imitating container mounted on outer surface of the ISS Service module (experiment "Matryeshka"). The objective was to compare doses inside the phantom in the container to human body donned in spacesuit "Orlan-M" during extravehicular activity (EVA). The shielding function was calculated using the geometric model, specification of the phantom shielded by the container, "Orlan-M" description, and results of ground-based estimation of shielding effectiveness by gamma-raying. Doses were calculated from the dose attenuation curves obtained for galactic cosmic rays, and the AE-8/AP-8 models of electron and proton flows in Earth's radiation belt. Calculated ratios of equivalent doses in representative points of the body critical organs to analogous doses in phantom "Matryeshka" H(ORLAN-M)/H(Matryeshka) for identical radiation conditions vary with organs and solar activity in the range from 0.1 to 1.8 with organs and solar activity. These observations should be taken into account when applying Matryeshka data to the EVA conditions.
Subject(s)
Cosmic Radiation/adverse effects , Extravehicular Activity , Phantoms, Imaging , Space Suits , Spacecraft , Dose-Response Relationship, Radiation , Gamma Rays , HumansABSTRACT
Goal of the investigation is to study and to analyze radiation dose distribution in cosmonaut's body during long-term mission aboard the International space station (ISS). The established patterns of dose distribution under different conditions of the experiment allow simplify evaluation of dose accumulation by spacecrew. Dose from ionizing space radiation was determined with the help of thermoluminescent dosimeters mounted in conditional depths of critical organs in human body modeled in a dosimetric device, i.e.--a ball-like tissue-equivalent phantom designed and manufactured in Russia for international space experiment Matreshka-R. The article reports experimental data disclosing the character and levels of exposure to ionizing radiation inside the Service module crew quarters during ISS missions 8 and 9 (425 days, 2004-2005) and the docking compartment (SO1) during ISS missions 15 and 16 (285 days, 2007-2008).
Subject(s)
Phantoms, Imaging , Space Flight , Thermoluminescent Dosimetry , Aerospace Medicine , Humans , Radiation Dosage , Russia , Time FactorsABSTRACT
Dynamics of the ISS RS radiation environment was studied using the data of daily (operative) monitoring and personal dose measurements during 11 increments in the period between August 1, 2000 and October 28, 2005 overlapping the maximum phase of the 23rd solar cycle. It was shown that personal absorbed doses varied within the range of measurements of dual wavelength radiometer R-16, a component of the ISS radiation monitoring system. Power of the absorbed doses fell in the range of 0.017 to 0.02 cGy/day and was solar-dependent.
Subject(s)
Astronauts , Radiation Injuries/diagnosis , Radiation Injuries/prevention & control , Spacecraft , Humans , Radiometry/instrumentation , Russia , Space FlightABSTRACT
The paper describes the procedure of estimating total radiation risk to crewmembers during lifetime and possible lifetime reduction in consequence of participation in the Mir and ISS missions in different periods of the solar activity. The procedure includes analysis of data of vehicle and personal dosimetry, and calculations of radiation doses in various Mir compartments and accumulated by body tissues of cosmonauts. Calculated doses showed good consistency with the doses measured with R-16 on board Mir and personal dosimeters. To a first approximation, estimation of doses to cosmonauts and radiation risk as a result of participation in ISS missions took into account similarity of the Mir and ISS basal modules (geometry, dimensions and mass values) and was performed with the use of the space station shielding model that had been described elsewhere. The model of ISS radiation shielding will be updated as data of dosimetry of ISS compartments and phantom studies are available.
Subject(s)
Astronauts , Health Status , Radiation Injuries/diagnosis , Radiation Injuries/epidemiology , Space Flight , Spacecraft , Humans , Models, Biological , Radiation Dosage , Risk FactorsABSTRACT
Cytogenetical studies of cosmonauts' peripheral blood lymphocytes after space flights on MIR orbital station showed a statistically significant increase in the yields of radiation-induced chromosomal aberrations. However, similar studies with in vitro irradiation of biological objects with accelerated charged particles are of great importance for elucidation of the nature of cytogenetical damage induced in vivo. It is also important to investigate the structure of cosmonatus' diseases over their life, in particular, lens opacities and oncological diseases. Thus, the purpose of the investigations planned is to study cytogenetical damage in blood lymphocytes from cosmonauts after space flights on the ISS in vivo, as well as in donor blood lymphocytes after in vitro exposure to accelerated charged particles. The tasks of the project are as follows: determination of the yields and types of chromosomal aberrations in cosmonauts' blood lymphocytes before and after space flights, comparative studies of biological effects induced in vitro by different types of ionizing radiation in human blood lymphocytes in ground experiments, assessment of cytogenetical risks, analysis of the structure of cosmonatus' diseases comparing with that of whole population, study of the mortality and frequency of cataracts and oncological diseases in cosmonauts. The results to be obtained will be used for setting of health norms applied to the influence of radiations of different types, and for elaboration of measures to reduce health risks from space flight factors.
Subject(s)
Astronauts , Health Status , Space Flight , Cosmic Radiation , HumansABSTRACT
An analysis was performed of unstable chromosomal aberrations in peripheral blood of 36 cosmonauts after long-term space missions on "Mir" orbital station. 25 cosmonauts were examined before their flights to score spontaneous yields of cytogenetical damage. In all cases the doses absorbed by crews during space flights did not exceed permissible levels of irradiation, adopted for cosmonauts. The frequencies of chromosomal-type aberrations after space missions were found to increase significantly compared to the pre-flight levels. The yields of dicentrics and centric rings on the average were as high as 0.12 +/- 0.02 and 0.47 +/- 0.06% before and after the 1st flight, 0.18 +/- 0.05 and 0.71 +/- 0.11% before and after the 2nd flight respectively. During the inter-flight periods, usually lasted 1.5-2 years, the yields of chromosome damage lowered, but did not reach their spontaneous values. After each next flight the yields of chromosome aberrations increased again. The cytogenetical damage detected in cosmonauts' peripheral blood lymphocytes after chronic action of low doses of space radiation points out a possible increase in risks of stochastic effects in distant future for crews after long-term space missions.
Subject(s)
Astronauts , Chromosome Aberrations , Lymphocytes/ultrastructure , Space Flight , Adult , Humans , Male , Middle Aged , Radiation DosageABSTRACT
The authors analyzed the data about seeds of higher plants obtained in space experiments from several days to a year and a half in duration, and ground-based simulation studies on beams of accelerated heavy ions by the universal biological criterion of the chromosome aberrations. The criterion was also used to compare these data with those about lymphocytes in human peripheric blood in vitro. The number of aberrant cells, including cells with multiple aberrations, grew with mission duration, absorbed dose, and fluence of heavy charged particles as well as the topography of particles traverse of cells. Methodical dimensions of the test-object as a detector to evaluate the biological effects of and risk from space radiation in long-term space missions are considered.
Subject(s)
Chromosome Aberrations/etiology , Chromosome Aberrations/genetics , DNA, Plant/genetics , DNA, Plant/radiation effects , Radiation Monitoring/methods , Seeds/genetics , Seeds/radiation effects , Space Flight , Chromosome Disorders , Dose-Response Relationship, Radiation , Germination/radiation effects , Humans , Lymphocytes/radiation effects , Radiation Dosage , Seeds/growth & developmentABSTRACT
The effect of cosmic radiation on air-dry lettuce (Lactuca sativa) seeds was investigated. It was attempted to discriminate the effects of cosmic ionizing radiation per se and its combination with solar light radiation. It was found that the number of aberrant cells in the seeds exposed to solar light was smaller than that of cells chielded with 0.0008 to 0.0035 g/cm2 foil which could be attributed to photoreactivity.
