ABSTRACT
The results are presented of measurements high-energy particles in a customary manned space station orbit (a 350-450-km altitude, a 51.6 degrees inclination; Salyut-6 and 7, MIR). The particles were recorded by the chambers composed of the Lavsan (polyethyleneterephtalate) solid-state nuclear track detector layers mounted outside a spacecraft for 1-3 years. A high resolution has been attained in the charge and energy spectra of 30-200 MeV/n Fe group particles. The results of measuring the particle fluxes in the space station orbits are used to restore the initial particle energy spectra in terms of the models that describe the galactic and solar cosmic rays and their penetration to the Earth's magnetosphere. The analysis demonstrates a high effectiveness of the described methods when applied to quite a number of space physics problems.
Subject(s)
Cosmic Radiation , Heavy Ions , Radiation Monitoring/instrumentation , Solar Activity , Space Flight/instrumentation , Elementary Particles , Extraterrestrial Environment , Iron , Linear Energy Transfer , Polyethylene Terephthalates , Radiometry , Spacecraft/instrumentationABSTRACT
This report presents the results of analyzing the relative importance of particle fluxes of different origin in the Earth-Mars-Earth route during different solar activity periods. The analysis has been made in terms of the galactic cosmic ray and solar energetic particle flux models developed at Moscow State University. The results demonstrate the extreme importance of the high-energy solar particle fluxes in interplanetary space even during the years of "quiet" Sun.
Subject(s)
Cosmic Radiation , Extraterrestrial Environment , Protons , Solar Activity , Earth, Planet , Mars , Models, Theoretical , Space FlightABSTRACT
The space radiation environment predicted for a spacecraft on the Earth-Mars-Earth route at different solar activity levels is analyzed in terms of the Russian-devised models.
Subject(s)
Radiation Protection , Solar Activity , Space Flight , Spacecraft , Earth, Planet , Electronics , Extraterrestrial Environment , Humans , Linear Energy Transfer , Mars , Models, Theoretical , Neutrons , Protons , Radiation Dosage , Silicon , Skin/radiation effectsABSTRACT
A wide range of the galactic cosmic ray and SEP event flux simulation problems for the near-Earth satellite and manned spacecraft orbits and for the interplanetary mission trajectories are discussed. The models of the galactic cosmic ray and SEP events in the Earth orbit beyond the Earth's magnetosphere are used as a basis. The particle fluxes in the near-Earth orbits should be calculated using the transmission functions. To calculate the functions, the dependences of the cutoff rigidities on the magnetic disturbance level and on magnetic local time have to be known. In the case of space flights towards the Sun and to the boundary of the solar system, particular attention is paid to the changes in the SEP event occurrence frequency and size. The particle flux gradients are applied in this case to galactic cosmic ray fluxes.
Subject(s)
Cosmic Radiation , Models, Theoretical , Protons , Solar Activity , Earth, Planet , Evaluation Studies as Topic , Extraterrestrial Environment , Magnetics , Space Flight , SpacecraftABSTRACT
The model is intended for calculating the probability for solar energetic particles (SEP), i.e., protons and Z=2-28 ions, to have an effect on hardware and on biological and other objects in the space. The model describes the probability for the > or = 10 MeV/nucleon SEP fluences and peak fluxes to occur in the near-Earth space beyond the Earth magnetosphere under varying solar activity. The physical prerequisites of the model are as follows. 1. The occurrence of SEP is a probabilistic process. 2. The mean SEP occurrence frequency is a power-law function of solar activity (sunspot number). 3. The SEP size (taken to be the > or = 30 MeV proton fluence size) distribution is a power-law function within a 10(5)-10(11) proton/cm2 range. 4. The SEP event particle energy spectra are described by a common function whose parameters are distributed log-normally. 5. The SEP mean composition is energy-dependent and suffers fluctuations described by log-normal functions in separate events.
Subject(s)
Forecasting/methods , Models, Statistical , Solar Activity , Cosmic Radiation , Extraterrestrial Environment , Heavy Ions , Mathematics , Probability , ProtonsABSTRACT
In the present paper the experimental and calculated data of SEU rate in microcircuits operating onboard spacecraft are compared. The main features of models and the calculation methods, which are incorporated in the SEREIS software package, are considered. The main features of models, and the calculation methods are considered. The contribution of the different space radiation components (ERB Protons; GCR particles and SEPs) to the SEU rate is discussed with an allowance for the shielding thickness.
Subject(s)
Cosmic Radiation , Microcomputers , Models, Theoretical , Protons , Software , Spacecraft/instrumentation , Databases, Factual , Earth, Planet , Extraterrestrial Environment , Magnetics , Radiation Monitoring , Radiation Protection , Solar Activity , Space Flight/instrumentationABSTRACT
Radiation characteristics (particle fluxes, doses, and LET spectra) are calculated for spacecraft in the International Space Station orbit. The calculations are made in terms of the dynamic model for galactic cosmic rays and the probabilistic model for solar cosmic rays developed at the Institute of Nuclear Physics of Moscow State University.
Subject(s)
Cosmic Radiation , Linear Energy Transfer , Models, Theoretical , Solar Activity , Spacecraft , Extraterrestrial Environment , Magnetics , Probability , Radiation Protection , Space FlightABSTRACT
Results of a detailed analysis of heavy ion fluences measured on the Salyut and MIR orbital stations from 1978 to 1990 are presented. The analysis has made use of new models that describe the cosmic ray fluxes and their transition through the magnetosphere. The penetration of solar cosmic ray particles to the orbit, the increase of the (Sc-Cr)/Fe flux ratio in the orbit, and the occurrences of 200-500 MeV/nucl heavy nuclei in <30 degrees latitudes have been analyzed.
Subject(s)
Cosmic Radiation , Heavy Ions , Radiation Monitoring/instrumentation , Solar Activity , Magnetics , Models, Theoretical , Space Flight/instrumentation , Spacecraft/instrumentationABSTRACT
Proton and neutron energy spectra behind Al shielding affected by galactic and solar cosmic ray particles are Monte-Carlo calculated using the multipurpose hadron transport code (SHIELD).
Subject(s)
Cosmic Radiation , Models, Theoretical , Neutrons , Protons , Solar Activity , Aluminum , Monte Carlo Method , Radiation Monitoring , Radiation ProtectionABSTRACT
The technique for evaluating the SEU rate induced by solar particle incidence on spacecraft microelectronics is described, including the contributions from the primary (heavy ion-induced) and secondary proton-induced) SEU mechanisms. The technique is based on original computational models for solar particle energy spectra and for SEU occurrence in electronics. The technique was used to analyze the data of the TDRS-1 Fairchild 93L422 IC exposed to protons and ions during the solar cosmic ray event of September-October 1989. The analysis included the distribution of the microcircuit shielding. A strong dependence of solar proton-to-ion ratio on the shielding thickness was indicated by the calculations.
Subject(s)
Cosmic Radiation , Electronics/instrumentation , Models, Theoretical , Protons , Solar Activity , Spacecraft/instrumentation , Equipment Failure , Linear Energy Transfer , Mathematics , Monte Carlo Method , Radiation Protection , Space FlightABSTRACT
A dynamic galactic cosmic ray model is proposed to quantitatively describe the z=1-28 ions and electrons of E=10-10(5) MeV/nucleon and their particle flux variations around the Earth's orbit and beyond the Earth's magnetosphere due to diverse large-scale variations of solar activity factors. The variations of large-scale heliospheric magnetic fields and the galactic cosmic ray flux variation time delays relative to solar activity variations are simulated. The lag characteristics and sunspot number predictions having been determined in detail, the model can be used to predict galactic cosmic ray flux levels.
Subject(s)
Cosmic Radiation , Elementary Particles , Extraterrestrial Environment , Models, Theoretical , Solar Activity , Magnetics , Mathematics , Nuclear PhysicsABSTRACT
The present paper analyses the problems of modeling galactic cosmic ray particle fluxes. A model representation which enables the particle energy spectra for large-scale solar activity induced modulations to be calculated is described.
Subject(s)
Cosmic Radiation , Models, Theoretical , Energy Transfer , Mathematics , Nuclear Physics , Solar ActivityABSTRACT
Fluxes of cosmic ray particles with different LET values were measured on board the Cosmos-2044 biosatellite under various thicknesses of shielding by stacks of CR-39 and nitrocellulose plastic nuclear track detectors (mounted outside the satellite). The component composition of the particles detected under shieldings of 0.1-2.5 g cm-2 is verified by comparing experimental data with the results of model simulations of the fluxes of galactic cosmic ray particles and of radiation belt protons.
Subject(s)
Cosmic Radiation , Elementary Particles/classification , Linear Energy Transfer , Radiation Monitoring , Space Flight/instrumentation , Computer Simulation , Protons , Radiation Protection/statistics & numerical data , SpacecraftABSTRACT
A new method of evaluating the charge state distribution of cosmic ray heavy ions, using a measured ratio of particle fluxes observed in two different satellite orbits passing through the Earth's magnetosphere, is described. The measurements of heavy ions were performed simultaneously on the Cosmos 1882 (orbital inclination 82 degrees) and Cosmos 1887 (inclination 62.3 degrees) satellites during September-October 1987. Solid state nuclear track detector stacks were used for the registration of C, N, O and heavier ions. After comparing the data of the two experiments with theoretical calculations, the charge state of galactic and anomalous heavy ions was derived.