This paper presents a novel design for a Dyson-Harrop CubeSat aimed at harvesting energy from the solar wind. Unlike current photovoltaic-based satellite energy generation, the Dyson-Harrop satellite generates energy ...This paper presents a novel design for a Dyson-Harrop CubeSat aimed at harvesting energy from the solar wind. Unlike current photovoltaic-based satellite energy generation, the Dyson-Harrop satellite generates energy based on the photoelectric effect, which has the potential to achieve significantly higher efficiency than current photovoltaic technology. The proposed CubeSat system consists of three main components: a tether unit, an energy harvesting unit, and the central 3U CubeSat body. The tether unit generates a cylindrical magnetic field along its main tether,effectively concentrating electrons from the solar wind to the energy harvesting unit. The energy harvesting unit includes a spherical electron receiver, functioning as a capacitor, which attracts electrons from the solar wind, as well as an annular flat solar sail that captures photons in the solar wind to eject electrons via the photoelectric effect, resulting in an electric current in the system.The Dyson-Harrop CubeSat is shown to be highly efficient as an energy-generation system, producing approximately 1 kW of power by a 3U CubeSat. This energy can be transmitted via microwave beams to other spacecraft or ground stations on the Earth. It is important to note that this estimation is based on first-principle estimations, and thorough theoretical analysis and experimental validation are required to confirm the feasibility of the concept.展开更多
The advanced infrared(IR) and microwave(MW) sounding systems have been providing atmospheric sounding information critical for nowcasting and improving weather forecasts through data assimilation in numerical weather ...The advanced infrared(IR) and microwave(MW) sounding systems have been providing atmospheric sounding information critical for nowcasting and improving weather forecasts through data assimilation in numerical weather prediction. In recent years, advanced IR and MW sounder systems are being proposed to be onboard CubeSats that are much more cost efficient than traditional satellite systems. An impact study using a regional Observing System Simulation Experiment on a local severe storm(LSS) was carried out to evaluate the alternative of using advanced MW and IR sounders for high-impact weather forecasting in mitigating the potential data gap of the Advanced Technology Microwave Sounder(ATMS) and the Cross-track Infrared Sounder(CrIS) on the Suomi-NPP(SNPP) or Joint Polar Satellite System(JPSS). It was found that either MicroMAS-2 or the CubeSat Infrared Atmospheric Sounder(CIRAS) on a single CubeSat was able to provide a positive impact on the LSS forecast, and more CubeSats with increased data coverage yielded larger positive impacts.MicroMAS-2 has the potential to mitigate the loss of ATMS, and CIRAS the loss of CrIS, on SNPP or JPSS, especially when multiple CubeSats are launched. There are several approximations and limitations to the present study, but these represent efficiencies appropriate to the principal goal of the study — gauging the relative values of these sensors.展开更多
Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors ...Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors the transient gamma-ray sky in the multi-mes-senger astronomy era.A compact CubeSat gamma-ray detector,including its hardware and firmware,was designed and implemented for the mission.The detector employs four Gd 2 Al 2 Ga 3 O 12:Ce(GAGG:Ce)scintillators coupled with four silicon photomultiplier(SiPM)arrays to achieve a high gamma-ray detection efficiency between 10 keV and 2 MeV with low power and small dimensions.The first detector designed by the undergraduate student team onboard a commercial CubeSat was launched into a Sun-synchronous orbit on October 29,2018.The detector was in a normal observation state and accumulated data for approximately one month after on-orbit functional and performance tests,which were conducted in 2019.展开更多
The two line elements(TLEs),released by the North American Aerospace Defense Command(NORAD),are chosen for CubeSats' mission operators.Unfortunately,they have errors and other accompanied problems,which cause larg...The two line elements(TLEs),released by the North American Aerospace Defense Command(NORAD),are chosen for CubeSats' mission operators.Unfortunately,they have errors and other accompanied problems,which cause large deviations in the in-track component.When a TLE value is available at a certain epoch,the dominant error is the angular error.It is proposed to correct the angular error by solving-for the mean argument of latitude at the desired epoch.A batch least squares technique and range rate measurements are used for the correction process.With the assistance of satellite tool kit(STK)software and Matlab,a simulation to verify the orbit determination(OD)technique is implemented.This paper provides an angular correction low cost OD method and presents a complete analysis for various test cases.This approach maintains high accuracy in cross-track and radial and makes great improvement in in-track at the same time,but it is exclusive for circular orbits.When it is applied to an elliptical orbit,the error will be unacceptable.Therefore,the angular error is corrected using the longitude of periapsis which totally mitigates the error at the epoch under consideration.For inclinations less than 20 o,the mean longitude is preferred for the angular correction as it provides more accuracy compared with the mean argument of latitude.展开更多
This paper reveals a new design of UHF CubeSat antenna based on a modified Planar Inverted F Antenna(PIFA)for CubeSat communication.The design utilizes a CubeSat face as the ground plane.There is a gap of 5 mm beneath...This paper reveals a new design of UHF CubeSat antenna based on a modified Planar Inverted F Antenna(PIFA)for CubeSat communication.The design utilizes a CubeSat face as the ground plane.There is a gap of 5 mm beneath the radiating element that facilitates the design providing with space for solar panels.The prototype is fabricated using Aluminum metal sheet and measured.The antenna achieved resonance at 419 MHz.Response of the antenna has been investigated after placing a solar panel.Lossy properties of solar panels made the resonance shift about 20 MHz.This design addresses the frequency shifting issue after placing the antenna with the CubeSat body.This phenomenon has been analyzed considering a typical 1U and 2U CubeSat body with the antenna.The antenna achieved a positive realized gain of 0.7 dB and approximately 78%of efficiency at the resonant frequency with providing 85%of open space for solar irradiance onto the solar panel.展开更多
The free space optical communication plays an important role in space-terrestrial integrated network due to its advantages including great improvement of data rate performance,low cost,security enhancement when compar...The free space optical communication plays an important role in space-terrestrial integrated network due to its advantages including great improvement of data rate performance,low cost,security enhancement when compared with conventional radio frequency(RF) technology.Meanwhile,CubeSats become popular in low earth orbit(LEO) network because of the low cost,fast response and the possibility of constituting constellations and formations to execute missions that a single large satellite cannot do.However,it is a difficult task to build an optical communication link between the CubeSats.In this paper,the cuttingedge laser technology progress on the CubeSats is reviewed.The characters of laser link on the CubeSat and the key techniques in the laser communication terminal(LCT) design are demonstrated.展开更多
CubeSats have evolved from purely educational tools to a standard platform for technology demonstration,scientific instrumentation and application in less than a decade.They open the door to new challenges and interpl...CubeSats have evolved from purely educational tools to a standard platform for technology demonstration,scientific instrumentation and application in less than a decade.They open the door to new challenges and interplanetary missions which lead to the direct realization of autonomous orbit determination(AOD)which has been investigated before with different integrated sensors combined with various filters.Mostly these studies were carried out for larger satellites with more accurate sensors.Magnetometer and sun sensor combined with extended Kalman filter(EKF)are chosen to complete AOD task considering their light weight.For the purpose of AOD and the computational cost requirements imposed on CubeSats,it is important to develop and apply low cost on-board models.In this perspective,a magnetic model based on a table look up is proposed to generate the reference magnetic field with a low computational burden.In current article the simulations through Matlab and Satellites Tool Kit(STK)especially focus on the accuracy of the AOD system provided by this model.For analysis three EKFs are carried out with different calculation models and data types.The system based on the proposed model is fully autonomous,low-cost and has moderate-accuracy required by most CubeSats missions.The AOD system can be applied as main or backup system depending on the space missions′demands.展开更多
As the role of missions and experiments carried out in outer space becomes more and more essential in our understanding of many earthly problems,such as resource management,environmental problems,and disaster manageme...As the role of missions and experiments carried out in outer space becomes more and more essential in our understanding of many earthly problems,such as resource management,environmental problems,and disaster management,as well as space science questions,thanks to their lower cost and faster development process CubeSats can benefit humanity and therefore,young scientists and engineers have been motivated to research and develop new CubeSat missions.Not very long after their inception,CubeSats have evolved to become accepted platforms for scientific and commercial applications.The last couple of years showed that they are a feasible tool for conducting scientific experiments,not only in the Earth orbit but also in the interplanetary space.For many countries,a CubeSat mission could prompt the community and young teams around the world to build the national capacity to launch and operate national space missions.This paper presents an overview of the key scientific and engineering gateways opened up to the younger scientific community by the advent and adaptation of new technology into CubeSat missions.The role of cooperation and the opportunities for capacity-building and education are also explored.Thus,the present article also aims to provide useful recommendations to scientists,early-career researchers,engineers,students,and anyone who intends to explore the potential and opportunities offered by CubeSats and CubeSats-based missions.展开更多
The FloripaSat-I project consists of an initiative from the Federal University of Santa Catarina(UFSC),in Brazil,to train students to design,test and integrate innovative space systems.The group just developed its fir...The FloripaSat-I project consists of an initiative from the Federal University of Santa Catarina(UFSC),in Brazil,to train students to design,test and integrate innovative space systems.The group just developed its first open-source CubeSat,the FloripaSat-I,which aims to empower students to develop space systems through a practical approach,where they have full control of the design and test of a real spacecraft.The project has already gone through all the stages of a CubeSat mission prior to the launching and operation stages.A prototype of the satellite,as well the engineering models 1 and 2(EM-I and EM-II)were built.The expertise provided by the engineering models allows the development of a functional flight model(FM).This paper presents the validation and qualification tests that pass various FloripaSat-I models,from the engineering model to the flight model.All stages of the project are described,the tests performed in each phase,as well as the lessons learned.Thus,this paper serves as a guidance for other university teams that want to test their own CubeSats,as well as teams that want to use the open-source hardware and software left as heritage by this project.展开更多
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
The Black Array of Broadband Absolute Radiometers Earth Radiation Imager(BABAR-ERI) is a small, adaptable nadir-pointed pushbroom imager to measure Earth-leaving broadband radiance from 0.3 ??m to 100 ??m with higher ...The Black Array of Broadband Absolute Radiometers Earth Radiation Imager(BABAR-ERI) is a small, adaptable nadir-pointed pushbroom imager to measure Earth-leaving broadband radiance from 0.3 ??m to 100 ??m with higher information content than is currently measured by reducing radiometric uncertainty and enabling cloud-resolving spatial resolution. The three-instrument BABAR-ERI suite fits a 12U CubeSat form factor and contains co-registered science telescope channels for measuring shortwave(0.3 ??m to 4.5 ??m band) and total radiance(0.3 ??m to 100 ??m band), dualchannel on-board radiance stability monitors, and a visible-wavelength camera. Novel, 1 × 32 element, electricalsubstitution radiometer pixels image the shortwave and total radiance in 1 km × 1 km co-registered ground footprints;longwave radiance(4.5 ??m to 100 ??m band) is derived from subtraction of the shortwave and total radiance. The dualchannel onboard stability monitors are radiance standard detectors, and their measurements, acquired concurrently with the science telescopes and at much different duty cycles for the dual channels, will be used to track and correct the degradation of the science channels. The single-channel, mid-visible camera facilitates geolocation pointing knowledge and provides scene context information and sub-pixel variability to facilitate measurement stability studies and enable process-level science studies at high spatial resolution. The detectors for the science channels and stability monitors are absolute, ambienttemperature, micro-fabricated, electrical-substitution radiometers with near-perfect optical absorptance across the measurement range from vertically aligned carbon nanotubes. The BABAR-ERI science channels will be characterized over the full measurement range and for variable Earth scenes and deep space temperatures during extensive ground calibrations.展开更多
Porous ionic liquid electrospray thrusters are the ideal propulsion technology for CubeSats because of their structural simplicity,high thrust accuracy and plume self-neutralization.The electrowetting technology can r...Porous ionic liquid electrospray thrusters are the ideal propulsion technology for CubeSats because of their structural simplicity,high thrust accuracy and plume self-neutralization.The electrowetting technology can replenish the propellant for the emitter online,thus prolonging the lifetime of the thruster.In order to gain a deeper understanding of its operating characteristics,the changes in thruster performance before and after propellant replenishment deserve to be scrutinized.In this study,the performance changes of a porous electrowetting ionic liquid electrospray thruster are tested by voltage-current test and time-of-flight mass spectrometry over a long operating time.The experimental results show that asymmetric operation with a negative current less than positive current for a long period of time causes anions to compensate for the emission after accumulation at the emitter,resulting in a phenomenon that the negative current is much larger than positive current.The reason for the difference in emission characteristics between the positive and negative modes is that the plume in the positive mode is quite ionized while the plume in the negative mode contains liquid droplets.This study provides a reference for the selection of operating conditions for ionic liquid electrospray thrusters.展开更多
The observation of the low-energyγ-ray(0.1 to 30 MeV)sky has been significantly limited since the COMPTEL instrument aboard the Compton Gamma Ray Observatory(CGRO)satellite was decommissioned in 2000.The exploration...The observation of the low-energyγ-ray(0.1 to 30 MeV)sky has been significantly limited since the COMPTEL instrument aboard the Compton Gamma Ray Observatory(CGRO)satellite was decommissioned in 2000.The exploration ofγ-ray photons within this energy band,often referred to as the MeV gap,is crucial to address numerous unresolved mysteries in high-energy and multi-messenger astrophysics.Although several large MeVγ-ray missions have been proposed(e.g.,e-ASTROGAM,AMEGO,and COSI),most of these are in the planning phase,with launches not expected until the next decade,at the earliest.Recently,there has been a surge in proposed CubeSat missions as cost-effective and rapidly implementable pathfinder alternatives.An MeV CubeSat dedicated toγ-ray astronomy could serve as a valuable demonstrator for large-scale future MeV payloads.This paper proposes aγ-ray payload design with a silicon-based tracker and a cesium iodide-based calorimeter.We report the results of a simulation study to assess the performance of this payload concept and compare the results with those of previousγ-ray instruments.As part of the performance assessment and comparison,we show that with our proposed payload design,a sensitivity better than IBIS can be achieved for energies between 0.1 and 10 MeV,and for energies up to around 1 MeV,the achieved sensitivity is comparable to COMPTEL,therefore opening up a window toward cost-effective observational astronomy with comparable performance to past missions.展开更多
基金supported by the Discovery grant(No.RGPIN-2024-06290)the CREATE grant(No.504156)of the Natural Sciences and Engineering Research Council of Canada.
文摘This paper presents a novel design for a Dyson-Harrop CubeSat aimed at harvesting energy from the solar wind. Unlike current photovoltaic-based satellite energy generation, the Dyson-Harrop satellite generates energy based on the photoelectric effect, which has the potential to achieve significantly higher efficiency than current photovoltaic technology. The proposed CubeSat system consists of three main components: a tether unit, an energy harvesting unit, and the central 3U CubeSat body. The tether unit generates a cylindrical magnetic field along its main tether,effectively concentrating electrons from the solar wind to the energy harvesting unit. The energy harvesting unit includes a spherical electron receiver, functioning as a capacitor, which attracts electrons from the solar wind, as well as an annular flat solar sail that captures photons in the solar wind to eject electrons via the photoelectric effect, resulting in an electric current in the system.The Dyson-Harrop CubeSat is shown to be highly efficient as an energy-generation system, producing approximately 1 kW of power by a 3U CubeSat. This energy can be transmitted via microwave beams to other spacecraft or ground stations on the Earth. It is important to note that this estimation is based on first-principle estimations, and thorough theoretical analysis and experimental validation are required to confirm the feasibility of the concept.
基金partly supported by the NESDIS OPPA OSSE program [grant number NA15NES4320001]
文摘The advanced infrared(IR) and microwave(MW) sounding systems have been providing atmospheric sounding information critical for nowcasting and improving weather forecasts through data assimilation in numerical weather prediction. In recent years, advanced IR and MW sounder systems are being proposed to be onboard CubeSats that are much more cost efficient than traditional satellite systems. An impact study using a regional Observing System Simulation Experiment on a local severe storm(LSS) was carried out to evaluate the alternative of using advanced MW and IR sounders for high-impact weather forecasting in mitigating the potential data gap of the Advanced Technology Microwave Sounder(ATMS) and the Cross-track Infrared Sounder(CrIS) on the Suomi-NPP(SNPP) or Joint Polar Satellite System(JPSS). It was found that either MicroMAS-2 or the CubeSat Infrared Atmospheric Sounder(CIRAS) on a single CubeSat was able to provide a positive impact on the LSS forecast, and more CubeSats with increased data coverage yielded larger positive impacts.MicroMAS-2 has the potential to mitigate the loss of ATMS, and CIRAS the loss of CrIS, on SNPP or JPSS, especially when multiple CubeSats are launched. There are several approximations and limitations to the present study, but these represent efficiencies appropriate to the principal goal of the study — gauging the relative values of these sensors.
基金supported by the Tsinghua University Initiative Scientific Research Program,the National Natural Science Foundation of China(Nos.11633003,12025301,and 11821303)the National Key R&D Program of China(Nos.2018YFA0404502 and 2016YFA040080X).
文摘Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors the transient gamma-ray sky in the multi-mes-senger astronomy era.A compact CubeSat gamma-ray detector,including its hardware and firmware,was designed and implemented for the mission.The detector employs four Gd 2 Al 2 Ga 3 O 12:Ce(GAGG:Ce)scintillators coupled with four silicon photomultiplier(SiPM)arrays to achieve a high gamma-ray detection efficiency between 10 keV and 2 MeV with low power and small dimensions.The first detector designed by the undergraduate student team onboard a commercial CubeSat was launched into a Sun-synchronous orbit on October 29,2018.The detector was in a normal observation state and accumulated data for approximately one month after on-orbit functional and performance tests,which were conducted in 2019.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China (No.20113219110025)
文摘The two line elements(TLEs),released by the North American Aerospace Defense Command(NORAD),are chosen for CubeSats' mission operators.Unfortunately,they have errors and other accompanied problems,which cause large deviations in the in-track component.When a TLE value is available at a certain epoch,the dominant error is the angular error.It is proposed to correct the angular error by solving-for the mean argument of latitude at the desired epoch.A batch least squares technique and range rate measurements are used for the correction process.With the assistance of satellite tool kit(STK)software and Matlab,a simulation to verify the orbit determination(OD)technique is implemented.This paper provides an angular correction low cost OD method and presents a complete analysis for various test cases.This approach maintains high accuracy in cross-track and radial and makes great improvement in in-track at the same time,but it is exclusive for circular orbits.When it is applied to an elliptical orbit,the error will be unacceptable.Therefore,the angular error is corrected using the longitude of periapsis which totally mitigates the error at the epoch under consideration.For inclinations less than 20 o,the mean longitude is preferred for the angular correction as it provides more accuracy compared with the mean argument of latitude.
文摘This paper reveals a new design of UHF CubeSat antenna based on a modified Planar Inverted F Antenna(PIFA)for CubeSat communication.The design utilizes a CubeSat face as the ground plane.There is a gap of 5 mm beneath the radiating element that facilitates the design providing with space for solar panels.The prototype is fabricated using Aluminum metal sheet and measured.The antenna achieved resonance at 419 MHz.Response of the antenna has been investigated after placing a solar panel.Lossy properties of solar panels made the resonance shift about 20 MHz.This design addresses the frequency shifting issue after placing the antenna with the CubeSat body.This phenomenon has been analyzed considering a typical 1U and 2U CubeSat body with the antenna.The antenna achieved a positive realized gain of 0.7 dB and approximately 78%of efficiency at the resonant frequency with providing 85%of open space for solar irradiance onto the solar panel.
文摘The free space optical communication plays an important role in space-terrestrial integrated network due to its advantages including great improvement of data rate performance,low cost,security enhancement when compared with conventional radio frequency(RF) technology.Meanwhile,CubeSats become popular in low earth orbit(LEO) network because of the low cost,fast response and the possibility of constituting constellations and formations to execute missions that a single large satellite cannot do.However,it is a difficult task to build an optical communication link between the CubeSats.In this paper,the cuttingedge laser technology progress on the CubeSats is reviewed.The characters of laser link on the CubeSat and the key techniques in the laser communication terminal(LCT) design are demonstrated.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20113219110025)
文摘CubeSats have evolved from purely educational tools to a standard platform for technology demonstration,scientific instrumentation and application in less than a decade.They open the door to new challenges and interplanetary missions which lead to the direct realization of autonomous orbit determination(AOD)which has been investigated before with different integrated sensors combined with various filters.Mostly these studies were carried out for larger satellites with more accurate sensors.Magnetometer and sun sensor combined with extended Kalman filter(EKF)are chosen to complete AOD task considering their light weight.For the purpose of AOD and the computational cost requirements imposed on CubeSats,it is important to develop and apply low cost on-board models.In this perspective,a magnetic model based on a table look up is proposed to generate the reference magnetic field with a low computational burden.In current article the simulations through Matlab and Satellites Tool Kit(STK)especially focus on the accuracy of the AOD system provided by this model.For analysis three EKFs are carried out with different calculation models and data types.The system based on the proposed model is fully autonomous,low-cost and has moderate-accuracy required by most CubeSats missions.The AOD system can be applied as main or backup system depending on the space missions′demands.
文摘As the role of missions and experiments carried out in outer space becomes more and more essential in our understanding of many earthly problems,such as resource management,environmental problems,and disaster management,as well as space science questions,thanks to their lower cost and faster development process CubeSats can benefit humanity and therefore,young scientists and engineers have been motivated to research and develop new CubeSat missions.Not very long after their inception,CubeSats have evolved to become accepted platforms for scientific and commercial applications.The last couple of years showed that they are a feasible tool for conducting scientific experiments,not only in the Earth orbit but also in the interplanetary space.For many countries,a CubeSat mission could prompt the community and young teams around the world to build the national capacity to launch and operate national space missions.This paper presents an overview of the key scientific and engineering gateways opened up to the younger scientific community by the advent and adaptation of new technology into CubeSat missions.The role of cooperation and the opportunities for capacity-building and education are also explored.Thus,the present article also aims to provide useful recommendations to scientists,early-career researchers,engineers,students,and anyone who intends to explore the potential and opportunities offered by CubeSats and CubeSats-based missions.
基金This work was supported by the Brazilian Space Agencythe National Council for Scientific and Technological Developmentthe Coordination for the Improvement of Higher Education Personnel.
文摘The FloripaSat-I project consists of an initiative from the Federal University of Santa Catarina(UFSC),in Brazil,to train students to design,test and integrate innovative space systems.The group just developed its first open-source CubeSat,the FloripaSat-I,which aims to empower students to develop space systems through a practical approach,where they have full control of the design and test of a real spacecraft.The project has already gone through all the stages of a CubeSat mission prior to the launching and operation stages.A prototype of the satellite,as well the engineering models 1 and 2(EM-I and EM-II)were built.The expertise provided by the engineering models allows the development of a functional flight model(FM).This paper presents the validation and qualification tests that pass various FloripaSat-I models,from the engineering model to the flight model.All stages of the project are described,the tests performed in each phase,as well as the lessons learned.Thus,this paper serves as a guidance for other university teams that want to test their own CubeSats,as well as teams that want to use the open-source hardware and software left as heritage by this project.
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.
基金supporting the BABAR array development and the BABAR-ERI instrument development (80NSSC20K0320)。
文摘The Black Array of Broadband Absolute Radiometers Earth Radiation Imager(BABAR-ERI) is a small, adaptable nadir-pointed pushbroom imager to measure Earth-leaving broadband radiance from 0.3 ??m to 100 ??m with higher information content than is currently measured by reducing radiometric uncertainty and enabling cloud-resolving spatial resolution. The three-instrument BABAR-ERI suite fits a 12U CubeSat form factor and contains co-registered science telescope channels for measuring shortwave(0.3 ??m to 4.5 ??m band) and total radiance(0.3 ??m to 100 ??m band), dualchannel on-board radiance stability monitors, and a visible-wavelength camera. Novel, 1 × 32 element, electricalsubstitution radiometer pixels image the shortwave and total radiance in 1 km × 1 km co-registered ground footprints;longwave radiance(4.5 ??m to 100 ??m band) is derived from subtraction of the shortwave and total radiance. The dualchannel onboard stability monitors are radiance standard detectors, and their measurements, acquired concurrently with the science telescopes and at much different duty cycles for the dual channels, will be used to track and correct the degradation of the science channels. The single-channel, mid-visible camera facilitates geolocation pointing knowledge and provides scene context information and sub-pixel variability to facilitate measurement stability studies and enable process-level science studies at high spatial resolution. The detectors for the science channels and stability monitors are absolute, ambienttemperature, micro-fabricated, electrical-substitution radiometers with near-perfect optical absorptance across the measurement range from vertically aligned carbon nanotubes. The BABAR-ERI science channels will be characterized over the full measurement range and for variable Earth scenes and deep space temperatures during extensive ground calibrations.
基金co-supported by the National Key R&D Program of China(Nos.2020YFC2201103 and 2022YFB4601300)the National Natural Science Foundation of China(No.U22B20120)+1 种基金the Program of Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology,China(No.Lab ASP-2024-09)the Beijing Institute of Technology Research Fund Program for Young Scholars,China。
文摘Porous ionic liquid electrospray thrusters are the ideal propulsion technology for CubeSats because of their structural simplicity,high thrust accuracy and plume self-neutralization.The electrowetting technology can replenish the propellant for the emitter online,thus prolonging the lifetime of the thruster.In order to gain a deeper understanding of its operating characteristics,the changes in thruster performance before and after propellant replenishment deserve to be scrutinized.In this study,the performance changes of a porous electrowetting ionic liquid electrospray thruster are tested by voltage-current test and time-of-flight mass spectrometry over a long operating time.The experimental results show that asymmetric operation with a negative current less than positive current for a long period of time causes anions to compensate for the emission after accumulation at the emitter,resulting in a phenomenon that the negative current is much larger than positive current.The reason for the difference in emission characteristics between the positive and negative modes is that the plume in the positive mode is quite ionized while the plume in the negative mode contains liquid droplets.This study provides a reference for the selection of operating conditions for ionic liquid electrospray thrusters.
基金supported by HKU-RMGS Funds (207300301 and 207301033principal investigator: Q.A.P.)+1 种基金The research of P.S.P. is partially supported by a General Research Fund (GRF) grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (HKU Project 17304920principal investigator: S. C. Y. Ng).
文摘The observation of the low-energyγ-ray(0.1 to 30 MeV)sky has been significantly limited since the COMPTEL instrument aboard the Compton Gamma Ray Observatory(CGRO)satellite was decommissioned in 2000.The exploration ofγ-ray photons within this energy band,often referred to as the MeV gap,is crucial to address numerous unresolved mysteries in high-energy and multi-messenger astrophysics.Although several large MeVγ-ray missions have been proposed(e.g.,e-ASTROGAM,AMEGO,and COSI),most of these are in the planning phase,with launches not expected until the next decade,at the earliest.Recently,there has been a surge in proposed CubeSat missions as cost-effective and rapidly implementable pathfinder alternatives.An MeV CubeSat dedicated toγ-ray astronomy could serve as a valuable demonstrator for large-scale future MeV payloads.This paper proposes aγ-ray payload design with a silicon-based tracker and a cesium iodide-based calorimeter.We report the results of a simulation study to assess the performance of this payload concept and compare the results with those of previousγ-ray instruments.As part of the performance assessment and comparison,we show that with our proposed payload design,a sensitivity better than IBIS can be achieved for energies between 0.1 and 10 MeV,and for energies up to around 1 MeV,the achieved sensitivity is comparable to COMPTEL,therefore opening up a window toward cost-effective observational astronomy with comparable performance to past missions.
