Purpose The Astro Bio Cube Sat(ABCS)was successfully deployed in its circular orbit at an altitude of 5850 km in the Van Allen Belt.Besides the primary mission of validating the analytical platform hosted in the paylo...Purpose The Astro Bio Cube Sat(ABCS)was successfully deployed in its circular orbit at an altitude of 5850 km in the Van Allen Belt.Besides the primary mission of validating the analytical platform hosted in the payload in such a harsh radiation environment,we used the telemetry data related to the dosimetry readings transmitted during the active mission period to back-validate the satellite’s radiation transport model,which was already used for the payload shielding design.Methods The radiation transport model was implemented with the high-energy Monte Carlo transport code FLUKA,and the definition of the orbital radiation sources were calculated using the SPENVIS code.In the actual work,the orbital radiation sources were defined at the mission epoch using SPENVIS and IRENE codes.In the FLUKA model,we implemented the dosimeters and further payload components,such as a battery pack and pump,which could furnish further shielding.The simulations executed with this upgraded model estimate the average dose rate measured during the mission period.To quantify the model validity,we compare the simulated dose rate with the one derived by fitting the telemetric integral dose data transmitted during the mission,finding a good agreement.An analysis of uncertainties and some consideration of space weather conditions are also considered to explain the agreement.Conclusion Based on the measured dose rate,the payload shielding was satisfactory.The agreement between the calculated and measured dose rates confirms the adequateness of the Monte Carlo model.Further work will be devoted to applying biasing techniques to speed up the simulation time.展开更多
Laminar natural convection heat transfer inside air-filled, rectangular enclosures partially heated from below and cooled at one side is studied numerically. A computational code based on the SIMPLE-C algorithm is use...Laminar natural convection heat transfer inside air-filled, rectangular enclosures partially heated from below and cooled at one side is studied numerically. A computational code based on the SIMPLE-C algorithm is used for the solution of the system of the mass, momentum, and energy transfer governing equations. Simulations are performed for a complete range of heater size, for Rayleigh numbers based on the height of the cavity ranging from 10~3to 10~6, and for height-to-width aspect ratios of the cavity spanning from 0.25 to 4. It is found that the heat transfer rate increases with increasing the heater size and the Rayleigh number, while it decreases with increasing the aspect ratio of the cavity. Dimensionless heat transfer correlations are also proposed.展开更多
Purpose The AstroBio Cube Satellite(ABCS)will deploy within the inner Van Allen belt on the Vega C Maiden Flight launch opportunity of the European Space Agency.At this altitude,ABCS will experience radiation doses or...Purpose The AstroBio Cube Satellite(ABCS)will deploy within the inner Van Allen belt on the Vega C Maiden Flight launch opportunity of the European Space Agency.At this altitude,ABCS will experience radiation doses orders of magnitude greater than in low earth orbit,where CubeSats usually operate.The paper aims to estimate the irradiation effect on the ABCS payload in the orbital condition,their possible mitigation designing shielding solutions and performs a preliminary representativity simulation study on the ABCS irradiation with fission neutron at the TAPIRO(TAratura Pila Rapida Potenza 0)nuclear research reactor facility at ENEA.Methods We quantify the contributions of geomagnetically trapped particles(electron and proton),Galactic Cosmic Rays(GCR ions),Solar energetic particle within the ABCS orbit using the ESA's SPace ENVironment information system.FLUKA(Fluktuierende Kaskade-Fluctuating Cascade)code models the ABCS interaction with the orbital source.Results We found a shielding solution of the weight of 300 g constituted by subsequent layers of tungsten,resins,and aluminium that decreases on average the 20%overall dose rate relative to the shielding offered by the only satellite's structure.Finally,simulations of neutron irradiation of the whole ABCS structure within the TAPIRO's thermal column cavity show that a relatively short irradiation time is requested to reach the same level of 1 MeV neutron Silicon equivalent damage of the orbital source.Conclusions The finding deserves the planning of a future experimental approach to confirm the TAPIRO's performance and establish an irradiation protocol for testing aerospatial electronic components.展开更多
基金supported by ASI/INAF agreement no.2019-30-HH.0。
文摘Purpose The Astro Bio Cube Sat(ABCS)was successfully deployed in its circular orbit at an altitude of 5850 km in the Van Allen Belt.Besides the primary mission of validating the analytical platform hosted in the payload in such a harsh radiation environment,we used the telemetry data related to the dosimetry readings transmitted during the active mission period to back-validate the satellite’s radiation transport model,which was already used for the payload shielding design.Methods The radiation transport model was implemented with the high-energy Monte Carlo transport code FLUKA,and the definition of the orbital radiation sources were calculated using the SPENVIS code.In the actual work,the orbital radiation sources were defined at the mission epoch using SPENVIS and IRENE codes.In the FLUKA model,we implemented the dosimeters and further payload components,such as a battery pack and pump,which could furnish further shielding.The simulations executed with this upgraded model estimate the average dose rate measured during the mission period.To quantify the model validity,we compare the simulated dose rate with the one derived by fitting the telemetric integral dose data transmitted during the mission,finding a good agreement.An analysis of uncertainties and some consideration of space weather conditions are also considered to explain the agreement.Conclusion Based on the measured dose rate,the payload shielding was satisfactory.The agreement between the calculated and measured dose rates confirms the adequateness of the Monte Carlo model.Further work will be devoted to applying biasing techniques to speed up the simulation time.
文摘Laminar natural convection heat transfer inside air-filled, rectangular enclosures partially heated from below and cooled at one side is studied numerically. A computational code based on the SIMPLE-C algorithm is used for the solution of the system of the mass, momentum, and energy transfer governing equations. Simulations are performed for a complete range of heater size, for Rayleigh numbers based on the height of the cavity ranging from 10~3to 10~6, and for height-to-width aspect ratios of the cavity spanning from 0.25 to 4. It is found that the heat transfer rate increases with increasing the heater size and the Rayleigh number, while it decreases with increasing the aspect ratio of the cavity. Dimensionless heat transfer correlations are also proposed.
基金the Italian Space Agency for co-funding the Cubesat 3U Astrobio ASI/INAF 2019-30-HH.0
文摘Purpose The AstroBio Cube Satellite(ABCS)will deploy within the inner Van Allen belt on the Vega C Maiden Flight launch opportunity of the European Space Agency.At this altitude,ABCS will experience radiation doses orders of magnitude greater than in low earth orbit,where CubeSats usually operate.The paper aims to estimate the irradiation effect on the ABCS payload in the orbital condition,their possible mitigation designing shielding solutions and performs a preliminary representativity simulation study on the ABCS irradiation with fission neutron at the TAPIRO(TAratura Pila Rapida Potenza 0)nuclear research reactor facility at ENEA.Methods We quantify the contributions of geomagnetically trapped particles(electron and proton),Galactic Cosmic Rays(GCR ions),Solar energetic particle within the ABCS orbit using the ESA's SPace ENVironment information system.FLUKA(Fluktuierende Kaskade-Fluctuating Cascade)code models the ABCS interaction with the orbital source.Results We found a shielding solution of the weight of 300 g constituted by subsequent layers of tungsten,resins,and aluminium that decreases on average the 20%overall dose rate relative to the shielding offered by the only satellite's structure.Finally,simulations of neutron irradiation of the whole ABCS structure within the TAPIRO's thermal column cavity show that a relatively short irradiation time is requested to reach the same level of 1 MeV neutron Silicon equivalent damage of the orbital source.Conclusions The finding deserves the planning of a future experimental approach to confirm the TAPIRO's performance and establish an irradiation protocol for testing aerospatial electronic components.
