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SPACEMON: Space Environment Monitoring Workshop 2020
The ESA Space Environments and Effects section (TEC-EPS), the Space Safety Programme (S2P) and the Space Environments and Effects Network of Technical Competences (SEENoTC) would like to invite you to the Space Environment Monitoring Workshop to be held on 1st - 3rd December 2020. This workshop is free and fully online but participation must be requested and approved. The purpose of this workshop is to present and discuss the current research and developments in the areas of space radiation, plasma and micro-particle monitoring plus magnetometers for space environment monitoring and atomic oxygen sensors. This includes exploitation of in-flight data to feed back lessons learned into ongoing and future monitor developments.
Whilst all abstracts will be considered, preference will be given to abstracts which are European-led or with a strong European component.
The nominal session overview is as follows:
The European Space Agency (ESA) has been flying space environment monitors for decades including a large number of radiation instruments, selected microparticle detectors and science-level plasma instrumentation. Payloads have been flown on scientific and navigation missions and more are planned for exploration, Earth exploration and telecommunication missions. Since 2009 ESA's Space Safety Programme (S2P - formally SSA) has been developing a space segment dedicated for operational space environment monitoring and space weather forecasting. S2P funds hosted payloads on missions as well as developing a dedicated space segment including the Lagrange mission and the Distributed Space weather Sensor System (D3S).
This presentation will outline the upcoming instruments being flown on ESA platforms, collaborations planned for additional sensors and future possibilities for flying space environment sensors which will contribute to ESA's space environment knowledgebase and space weather network.
Since more than 25 years, the CNES has led an in-flight monitoring activity within our technology program. This activity is based on an instrument, ICARE, which has evolved over time to fulfill new detection and mission needs. Our approach is PI-driven, in partnership with ONERA. ONERA defines the sensor heads, determines the response functions, and interprets the data. CNES takes in charge the development of electronics and interfaces, realization, integration and qualification, and the level 0/1 ground segments. Missions have been made in cooperation with RKA Energia (MIR, ISS), with the Argentinian Space Agency CONAE (SAC-C, SAC-D), with JAXA within the Jason consortium CNES, JPL, NOAA, EUMETSAT (Jason-2, Jason-3), with EUTELSAT and MAXAR - ex Space Systems Loral (Eutelsat 7C). An overview of the past missions and future plans, and obtained results will be made
DLR Space Administration through its Department for Space Situational Awareness is active in different areas of Space Debris research and Space Weather. I will present a short overview of current activities in these areas, as well as our involvement in qualification of components.
Building on over a half century of atmospheric science and space physics engineering, OHB Sweden has developed a key competence in science-specific smallsat missions. The journey began already in the 1960s with the focus on sounding rockets and balloon payloads from northern Sweden, but evolved in to orbital satellites with the first Swedish plasma physics mission, Viking, in 1986. Since then Sweden has had a continuous role in atmospheric science and space physics in a sequence of missions leading up to the creation of the InnoSat Program. Though primarily created by the Swedish National Space Agency to address national specific academic and research needs, the program has a longer goal of serving as a science platform within newer, smaller ESA programs. This is now underway with recent missions such as the Arctic Weather Satellite (AWS) demonstration and eventual constellation, and the Space Weather Satellite (SWS) constellation.
This presentation intends to briefly show this Swedish space development history, introduce the national InnoSat program and describe what is coming in the future for AWS and SWS missions.
SSTL is one of the world’s leading small satellite providers and has a rich history dating back to its establishment in the mid 1980’s in providing flight opportunities for environment monitoring instruments, especially benefitting those seeking a low cost approach and short timescales to the flight. This has included hosting environment monitoring instruments on commercial missions, as well being prime contractor on the dedicated UK demonstration mission TechDemoSat-1 which included several environment monitoring instruments. Additionally SSTL has flown (or is planning to fly) its own environment monitoring instrument, the RADMON, on a number of its own spacecraft to provide enhanced monitoring and diagnostic capability. Such a RADMON will also fly on each of the two spacecraft in the joint US-UK CIRCE space weather mission next year.
This talk will provide an SSTL perspective on flight opportunities for environment monitoring instruments including past heritage and an overview of currently ongoing/planned mission and spacecraft activities at SSTL, which could present potential flight opportunities for environment monitoring instruments, either as hosted payloads or even dedicated missions. The potential for offering a service using RADMON data on future SSTL spacecraft will also be briefly discussed.
The RESISTACK sensor consists in a stacking of metallized polymer films acting as a set of resistances in parallel. The total resistance of the detector shows step increases each time a layer is fully eroded (opens “switch”). The detection of these steps allows correlating with AO fluence.
The number and thickness of layers define the range of fluence that can be monitored and the accuracy of detection. Minimum fluence detection is currently 3-4 1020 AO/cm² (with 12.5µm Kapton films). RESISTACK with up to 5 layers have been successfully manufactured using compatible space qualified PCB process allowing:
• low cost (batches of 10 devices)
• low weight (few grams)
• and no consumption while exposed (only during periodic reading i.e. resistance measurement, few 10-100 ohms).
This sensor was validated at ground (AO testing, thermal cycling, vibration planned). It is currently planned to fly aboard the Ageing Material Experiment (ISS/Bartolomeo) with 2 configurations:
• 2D or direct AO detection (facing RAM)
• 3D or indirect detection of secondary AO (after AO reflection on selected materials)
The surface of detection is 1.6 x 1.6 cm² (sensor dimension is 3 x 4 cm²)
The concept and design of this sensor belongs to ONERA (DPHY department) and the development and validation is supported by CNES.
An Ion and Neutral Mass Spectrometer (INMS), designed for sampling of low mass ionised and neutral particles in the spacecraft ram direction, was developed for the EU QB50 CubeSat constellation mission. 9 INMS instrument were launched on their respective educational CubeSats and to date, data has been returned for a one month period from the one working QB50 CubeSat. Two further sensors are due to be launched in mid-2021 on the CIRCE mission. Subsequently, an enhanced performance INMS has been developed for the Satellite for Aerodynamic Research (SOAR), a CubeSat being developed for the H2020 DISCOVERER project, currently scheduled for launch in May 2021. The instrument is a gated time-of-flight and will add a velocity measurement capability to the INMS. Both the INMS instruments are suitable for measurement of Atomic Oxygen (AtOx) in LEO. This paper will present an overview of the instrument designs, some preliminary results of in-flight AtOx measurements from the QB50 INMS and an outlook of expected measurements from CIRCE and SOAR.
LISA Pathfinder (LPF) was the European Space Agency (ESA) technology demonstrator of the Laser Interferometer Space Antenna (LISA). The LPF spacecraft (S/C) was orbiting at about 1.5 x 10^6 km away from the Earth around the first Sun-Earth Lagrangian libration point (L1). Using fluxgate platform magnetometer measurements, it was possible to resolve the magnetic field generated on board (typically ~1 μT) from that of interplanetary origin (1-25 nT). The technique here proposed can be applied in the case of any other S/C carrying on board platform magnetometers, provided the availability of the entire housekeeping dataset.
In the frame of the ESA SSA program a four-sensor Service Oriented Spacecraft Magnetometer (SOSMAG) was launched with GEO-KOMPSAT-2A into a geostationary orbit on December 4th 2018. The instrument is designed for magnetic field measurements onboard of satellites which are developed without magnetic cleanliness requirements. The multi sensor arrangement is used for eliminating spacecraft generated AC disturbances onboard, so that corrected data can be transmitted in real time to Earth.
The presentation gives an overview about the capability and limitation of a multi sensor application. We will discuss the compliance of SOSMAG sensor performance, sensor setup and data correction with requirements on accuracy for space weather investigations.
In September 2018, a photographic survey of the outer surface of the Columbus module of the International Space Station (ISS) with emphasis on the forward facing areas was conducted to obtain information on the space debris and meteoroid environment at the ISS orbit. Video footage from the camera installed at the tip latching end effector (LEE) of the robotic arm (space station remote manipulator system, or SSRMS) comprises the primary data. This survey could be conducted thanks to the preparation effort of a team around DLR GSOC, University Oldenburg, DLR Institute of Space Systems, TU Braunschweig and Fraunhofer EMI, as well as the kind and substantial support from NASA and ESA. The main aim of the survey is to generate measurement data for particle environment models such as MASTER and ORDEM.
During analysis of the video data it became apparent that it is not sufficient to only identify and size craters in the videos, but that good position information is required for an accurate analysis of the data. The determination of the position of each individual video frame turned out to be non-trivial, since data from a variety of sources needed to be integrated: NASA SSRMS procedures, LEE geometry information, camera lens information, and Columbus module geometry information. The NASA SSRMS procedures used are incomplete in terms of the velocity of the camera, and only contain the start and end coordinates for each row. Therefore, the framewise camera displacement was extracted from the video data. Combining all this data allowed to localize each individual video frame.
In a second step, an algorithm was developed to automatically derive the size and position of the craters visible in the videos. This includes automatic processing of each individual video frame and tracking craters across multiple frames, thus combining all available data to obtain as precise as possible information on each individual crater. To size the craters in the video, a crater generated in a hypervelocity impact experiment at one of Fraunhofer EMI’s two-stage light-gas guns was performed, and the resulting crater investigated by the same method. The final algorithm was tested on a part of the ISS survey video.
The presentation will provide an overview on both algorithms (video frame localization, and crater localization with sizing), show the current status of the analysis of the dataset at Fraunhofer EMI, and give some insights into the problems encountered during the analyses. Since the analysis is still on-going, an outlook on the expected results will also be given.
Small space debris objects and micrometeoroid particulates (collectively called microparticles) pose a significant threat to the safe operations of satellites and other space systems in Earth orbit. Depending on particle’s size, speed, and impact angle, hypervelocity particle impacts can degrade surfaces, puncture outer walls, damage internal components, and in the worst case lead to the partial or complete destruction of the spacecraft.
Since they cannot be detected/tracked by ground-based radar or optical instruments, the impact fluxes of particles smaller than a few centimeters in LEO or a few decimeters in GEO are not well known. As a consequence, microparticle environment models (e.g. MASTER, ORDEM) have large flux uncertainties (up to a factor of 3, and in certain sizes ranges larger still).
Therefore, it is of paramount importance to have reliable data from in-situ microparticle detectors to validate and improve MMOD environment models. Furthermore, long-term measurements provide valuable information on the temporal evolution of the small-sized space debris population.
Several European in-situ microparticle detectors have flown or are still gathering data in LEO and GEO. The Geostationary Orbit Impact Detector (GORID) has been detecting impacts onboard the Russian Ekspress-2 geostationary satellite from 1996 till 2001. DEBIE-2 (Debris In-orbit Evaluator) provided data from the ISS/Columbus module for about one year. Finally, DEBIE-1 onboard the Proba-1 satellite is still going strong despite almost 20 years of operation in a Sun-synchronous LEO orbit.
In this talk we will present a summary of the data collected so far and some key findings based on preliminary processing/analysis. The recent update to the European Debris Impact Database (EDID) for storing, processing, disseminating data from debris and meteoroid impact detectors will be presented.
Given the importance of having continuous measurements of reliable microparticle fluxes in congested orbital regimes, we invite ESA to renew efforts to process and analyse existing events as found in the EDID database, use the impact data to validate/improve microparticle environment models (e.g. MASTER), plan for new R&D activities on microparticle detectors, and identify suitable flight opportunities. Furthermore, we would like to encourage the microparticle detector community to add their data to the EDID database, e.g. TechnoSat/SOLID data.
The Orbiting Dust Impact Experiment (ODIE) is a dedicated, retrievable, passive dust collector, designed to be placed on, for example, the outside of the International Space Station to facilitate the investigation of the flux and origin (orbital debris OD vs micrometeoroid MM), of dust particles in Low Earth Orbit (LEO). ODIE is comprised of multiple layers of polymer foils that act in much the same way as a Whipple shield: the initial foil(s) disrupt the impactor, spreading its energy over a larger surface and capturing multiple lower speed fragments on subsequent foils. Polymer foils used in multi-layer insulation exposed to LEO have been found to capture and retain substantial quantities of easily identifiable residue that may be analysed to determine chemistry, and thus identify OD vs MM origins of the impacting particle. Laboratory experiments have shown that impacting particles ranging in size from a few µms to mms leave behind residues on all foils that they contact and that the dimensions of the impacting particle may be estimated from the size of the crater/penetration hole they create on the front foil. Upon retrieval of ODIE after a minimum deployment of 12 months, impact features can be analysed using a suite of analytical techniques that are typically too large for use in space (e.g. Scanning Electron Microscope, SEM) and thus determine the flux of OD and MM populations in LEO.
Our proposed design comprises 4 polymer foils (Kapton) with thicknesses ranging from 25 µm (front foil) to 125 µm (rear foil). The total surface area of ODIE should be as large as possible to maximise the number of particles collected, however, we have designed the collector to be composed of smaller cells measuring 10 cm x 10 cm to facilitate manufacture, handling and post-retrieval analysis. These cells comprise of an Al frame, within which 1 cm thick plastic support frames ensure the foils are evenly spaced. As ODIE is to be placed in LEO, each foil requires coating to prevent erosion by atomic oxygen (AO). Conventional coatings of Al and Au have the potential to hinder the identification of OD and MM residues thus we have chosen to coat our foils with Pd. Coating the foils also facilitates post-retrieval identification of impact features with holes/craters appearing dark against the bright coated foil in SEM backscattered electron images.
The Light Gas Gun (LGG) at the University of Kent is being used to test ODIE and determine the relation between the size/composition of impactors and the impact features/residues they generate and to discover how these change as impact velocity, impact angle, projectile composition and projectile size are varied. Modelling is also being performed to extrapolate to higher velocities than achievable in the LGG (>7 km/s). We also aim to evaluate our Pd coated foils’ resilience to AO and perform thermal, vacuum and vibrational tests and combine all results to advance ODIE technology to Technology Readiness Level 5.
The SafeSpace project aims at advancing space weather nowcasting and forecasting capabilities and, consequently, at contributing to the safety of space assets through the transition of powerful tools from research to operations (R2O). This will be achieved through the synergy of five well-established space weather models (CNRS/CDPP solar disturbance propagation tool, KULeuven EUHFORIA CME evolution model, ONERA Neural Network tool, IASB plasmasphere model and ONERA Salammbô radiation belts code), which cover the whole Sun – interplanetary space – Earth’s magnetosphere chain. The combined use of these models will enable the delivery of a sophisticated model of the Van Allen electron belt and of a prototype space weather service of tailored particle radiation indicators. Moreover, it will enable forecast capabilities with a target lead time of 2 to 4 days, which is a tremendous advance from current forecasts that are limited to lead times of a few hours. SafeSpace will improve radiation belt modelling through the incorporation into the Salammbô model of magnetospheric processes and parameters of critical importance to radiation belt dynamics. Furthermore, solar and interplanetary conditions will be used as initial conditions to drive the advanced radiation belt model and to provide the link to the solar origin and the interplanetary drivers of space weather. This approach will culminate in a prototype early warning system for detrimental space weather events, which will include indicators of particle radiation of use to space industry and spacecraft operators. Indicator values will be generated by the advanced radiation belt model and the performance of the prototype service will be evaluated in collaboration with space industry stakeholders. The work leading to this paper has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870437 for the SafeSpace (Radiation Belt Environmental Indicators for the Safety of Space Assets) project.
ESA’s Space Environment Information System (SPENVIS, https://www.spenvis.oma.be) is providing interfaces to various models and tools that can be employed for scientific studies related to the characterisation of the space environment and its effects. In particular, users can employ these tools to verify instrument and detector responses, optimise space radiation shielding and investigate radiation-induced effects on spacecraft components.
The last years have seen a renewed interest in the exploration of the Moon and the possibility for commercial exploitation of its resources. The characterisation of the radiation environment on the Moon is an important element for designing any lunar-based asset. In this talk, we will show how someone can use SPENVIS to perform a lunar radiation environment specification and analysis. Naturally, the primary radiation environment is due to Galactic Cosmic Rays (GCR) and Solar Energetic Particles (SEP) reaching the surface of the Moon. However, it is important to look also at the lunar albedo secondary particles generated from the interaction of the incident high-energy particles with the lunar soil. As an example, we will present the work done in support of the design of a miniature X-Ray Fluorescence (XRF) spectrometer for a future ESA mission to the Moon.
A CubeSat constellation platform has been found to be a tempting and cost-effective solution for monitoring of space weather at LEO, which would complement higher altitude space weather observations, providing data for validation of space weather models and using assimilation for better spatial and temporal resolution, thus enabling downstream services for operational use in aviation and other user sectors. A constellation with continuous monitoring capability of solar X-ray fluxes and spectra, high-energy particles, and ionospheric electron density variability would be a suitable solution for such purpose.
There are already high-TRL solutions for space weather instruments adapted for CubeSats, like the XFM-CS for the Sunstorm 1 mission (ESA) and high-energy particle monitors. Radio beacons with high TRL and CubeSat platforms are also available, and already in use for the space weather instruments and other purposes. We present a CubeSat constellation concept suitable for space weather at LEO including the platform, payload, and the ground segment, and discuss the use of the data from the system for new space weather services.
Summary:
INTA has the opportunity to fly a radiation monitor on-board the long duration stratospheric balloon flight Sunrise III as part of the TuMag Collaboration instrument.
The requirements of this monitor are:
• It should be completely autonomous, in terms of mechanical integration, power supply, data acquisition and storage during a long duration flight of at least 10 days.
• It should be simple, light-weight, robust, easy to integrate and operate, and low cost.
• It should detect primary cosmic rays events, measuring pulse amplitudes, and classify low energy particle and high energy particle detection events to calculate their relative flux.
This presentation will outline the solution developed by the Spanish SME Hidronav Technologies (http://www.hidronav.com/page2.html) based on the optimization and integration of two CosmicWatch desktop muon detector units (MIT open project development, http://www.cosmicwatch.lns.mit.edu/), based on small plastic scintillator slabs (25cm3), silicon photomultiplier readout and Arduino microcontroller.
Using the large data set of single and coincidence detection events from both scintillators, recording pulse amplitude measurements (and thereby energy deposition estimation), together with time-stamp and GPS location data, different particle fluxes will be derived and compared to previously simulated data. Cosmic-ray fluxes of different particles, at different locations along the balloon flight have been calculated by the PARMA model.
The 3DEES is conceived as a compact and modular science-class spectrometer allowing angle resolved high electron energy coverage (0.1 – 10 MeV) using a few sensors. Its baseline set-up provides capabilities to measure angular distribution of electrons and protons at 12 angles spanning over 180° in two planes. The 3DEES also allows measurements of proton fluxes (4-50 MeV), while performing absolute electron-proton discrimination for protons up to 200 MeV.
The 3DEES is built within a consortium including QinetiQ Space, the Belgian Institute for Space Aeronomy (BIRA/IASB) and UCLouvain. A first technology demonstration model is foreseen to fly on-board PROBA-3, actually programmed to be launched in 2022 into a highly elliptical orbit: 60 530 km apogee, 600 km perigee, 59° inclination, 19.7 hours orbital period. With these orbital parameters, the satellite will cover parts of the inner belt, outer belt and mostly the boarder of the magnetosphere. Hence, the ultimate objectives of the 3DEES mission are to give an accurate picture of the high-energy electron population in the magnetosphere for scientific studies of their acceleration and loss processes and to deliver Space Weather data for now- and forecasting activities. It completes the PROBA-V/EPT (Energetic Particle Telescope) mission with additional data at high altitude.
The talk will give a general presentation of the instrument wherein the main features of the 3DEES will be revisited, focusing on the design, building and calibration of the prototype sensor stack that includes four 1.5 mm thick sensors and adjacent electronics and which particularity is that it is moulded in order to achieve miniaturization and mechanical robustness. Finally, the planned accommodation of 3DEES on-board PROBA-3, the concessions and technical updates that needed to be done due to its proposed late integration, will shortly be described.
ICARE-NG is a radiation monitor already embedded in several space missions such as SAC-C, SAC-D, JASON2, JASON3 and more recently E7C.
Composed of several detection heads, a wide range of electron and proton energies can be measured. Initially designed with three detection heads, the geometries have recently been revised in order to integrate a new low-energy proton detection head. To guarantee an accurate discrimination of ionizing particles in a mixed field as radiation belts, magnets are used to deflect incident electrons. Moreover, a suitable shielding composed of aluminium and tungsten materials have been determined to reduce high-energy proton and bremsstrahlung contributions. The range of measured energies is now extended and protons from 2 MeV to 300 MeV can be measured.
Deposited energies are sampled by ICARE-NG as counts and methods for converting these counts to fluxes are needed. Recently, a dedicated Machine Learning algorithm have been developed and promising results were obtained.
Mission
NORM is the Norwegian Radiation Monitor for measuring energetic charged particle radiation in space. NORM is designed as an easily adaptable space radiation monitor for satellite missions in GEO, LEO, and HEO. The development is funded by ESA.
NORM’s first flight will be on the Arctic Satellite Broadband Mission (ASBM) in a highly-elliptical three point apogee orbit (HEO-TAP). The ASBM mission lifetime is 15 years, NORM will be operated for at least 5 years.
Since the ASBM’s HEO orbit is unique and traverses different radiation environment domains, the prediction of the radiation environment for this mission comes with some uncertainty. That is why NORM will be useful to validate existing and new radiation environment models by its data taking aboard the ASBM spacecraft.
Particle Detection
NORM allows to measure the rate and kinetic energy of electrons (0.5 – 7 MeV) and protons (7 – 200 MeV) in space. The resulting coarse differential flux spectra for electrons and protons allows for rough dosimetry, characterisation of the radiation environment and its variation over time.
System Design
The NORM instrument is made up of two main physical units, the Data Handling Unit (DHU) and the Data Gathering Unit (DGU). The DGU contains the radiation detector and integrated readout electronics utilising the IDEAS IDE3466 readout ASIC. The radiation detector is a particle telescope made of 9 silicon diodes and aluminium/tantalum absorbers shielded in a cylindrical vault. The diodes generate an electrical charge when they are exposed to charged particles. The trigger pattern of the diode stack is evaluated in the IDE3466 ASIC to classify the particle types and kinetic energy. In addition, the condition for coincidence trigger patterns suppresses background from particles outside the intended field-of-view. A dual-layered radiation shielding further reduces undesired background radiation.
To compensate for detectors optimised for each type of radiation NORM will take full advantage of the programmable thresholds and patterns being able to quickly reconfigure the instrument, in-flight calibration and attention to instrument noise considerations from an early stage that is critical for electron and high-energy proton detection capability.
The DHU hosts the data processing and power supply. We use the new Microchip SAMRH71 ARM microcontroller for interfacing with the IDEAS IDE3466 ASIC and for receiving commands and transmitting telemetry over the satellites MIL-STD-1553B bus. The SAMRH71 also provides a CAN and a SpaceWire bus, opening up the possibility of using NORM on other satellites as well. No FPGA is used.
Status
By the time of SPACEMON 2020 NORM the engineering model will be available with on-going testing. Qualification is scheduled for the first half of 2021 and we hope to deliver the flight unit in the summer of 2021, which is arguably an ambitious schedule, especially in the times of the Corona pandemic. The launch of the ASBM satellites is planned for late 2022.
The High Energy Particle Spectrometer (HEPS) belongs to the in-situ instrument suite developed for the ESA Lagrange mission. HEPS is designed for spectroscopic measurements of charged particles from the Solar Energetic Particle events. Its dynamic range is optimized for operating conditions from typical to extreme solar events. The instrument measures electrons, protons, and heavy ions in extended ranges of particle energies and their incoming angles. Angular distributions of incoming particles are measured with dedicated direction sensitive sensors. Detection systems devoted for measurements of electrons and protons use Si and SiC sensors and previously developed readouts. The heavy-ion detector (HIT) is a novel design utilizing telescope-arranged scintillators coupled to the SiPMs. HIT electronics is equipped with a dedicated ASIC optimized for fast signal processing. A prototype model of HIT detector and electronics was used to verify its energy range and ion identification requirements. Several heavy ion test campaigns were carried out at two facilities confirming HIT performance. Intensive simulations and optimization of instrument responses were conducted in parallel. We will present experimental data from the heavy ion tests and analyze energy range and resolution aspects as well as ion separation features. Monte Carlo simulations will be discussed for particle responses as well as instrument performance during extreme solar events with very large particle fluxes. Implications on further optimization and its final design of HEPS will be presented.
The D3S-RADMAG radiation monitor and space weather instrument concept is aimed to provide a market product combining the radiation and magnetic field measurement capability into one payload to be directly applicable within the D3S hosted payload concept of ESA. The instrument Radiation Monitor Unit (RM-RAD) includes a sophisticated, complex silicon detector based telescope, called RADTEL, with its associated interpretation logic behind. The telescope responses were modelled with a Monte Carlo tool called GRAS (Geant4 Radiation Analysis for Space) that was developed by the European Space Agency and based on the Geant4 toolkit. For the first study a simple spectrum, the descending branch of the function 1/x, was used for both protons and electrons in the corresponding energy range of interest. Based on these results the possible detector responses could be calculated and the initial logic for the channels were modified and optimized. Later this simple spectrum could be rescaled to several characteristic real like spectra to calculate the relative accuracies, contaminations and possible corrections to these.
Penetrating particle Analyzer (PAN) is a magnetic spectrometer designed for deep space science and interplanetary missions. It can measure the energetic particles in precision, monitoring the cosmic rays physics, solar physics, space weather, etc, and spanning over more than 1 full solar cycle. The spectrometer is in a limited mass ~ 20 kg and limited power consumption ~20 W, which facilitate it as a standard on-board instrument for human space travel. The detector adopts novel particle detection technologies, including a dipole magnet sectors, which allows an energy resolution of better than 10%; a plastic scintillator based time-of-flight system read out by SiPMs with time resolution of 100 ps; a silicon pixel detector operating in low power mode while maintaining the capabilities of high rate identification; and a silicon tracker to determine particles.
The JUpiter ICy moons Explorer (JUICE) is the European Space Agency (ESA) next large class mission to the Jovian system. The mission, planned for a launch in 2022 and a 7.5-year long cruise to the planet, will investigate Jupiter and characterize its icy moons, Callisto, Europa and Ganymede for a period of 3.5 years.
The Jovian system is known to have a harsh and energetic radiation environment with a large population of electrons reaching energies well above 10 MeV. For this reason, the JUICE mission will include the RADiation hard Electron Monitor (RADEM), a low power, low mass radiation monitor, currently under development by LIP, PSI, EFACEC and IDEAS.
RADEM will the first dedicated mission to expand energy measurements of the particle population done by the Galileo Energetic Particle Detector (the JUNO mission does not carry a radiation monitor), while providing housekeeping support to the spacecraft. The instrument consists of three detector heads based on standard silicon stack detector technologies: the Electron Detector Head (EDH), the Proton Detector Head (PDH), and the Heavy Ion Detector Head (HIDH). Because the detectors have limited Field-Of-View, a fourth detector, the Directionality Detector Head (DDH) will measure electron angular distributions. Stacked detectors will cover the following energy range: from 0.3 MeV to 40 MeV for electrons, from 5 MeV to 250 MeV for protons and from 8 to 670 MeV for Heavy Ions from Helium to Oxygen. The role of the DDH is of utmost importance since it has been shown by the Galileo mission that electron fluxes vary spatially e.g. as results of interaction with the Ganymede magnetosphere. Taking it into account will prevent to under or overestimate the spatially integrated particle flux and in consequence the Total Ionizing Dose.
In this work we will present the status of the instrument with a large emphasis on the latest results from proton and low energy electron testing done with the RADEM Engineering Model. The high energy electron testing (up to 40 MeV) done to the detector’s breadboard model will also be presented. The current results show full compliance with the technical requirements. Further calibrations and tests of the Proto-Flight Model are scheduled for the beginning of 2021. The scientific opportunities of the RADEM for the whole JUICE mission will also be discussed.
ESA’s Space Safety & Security activities are aimed at monitoring and mitigating the impact of space hazards to critical infrastructure. One of the cornerstones of these activities is development of a Space Weather monitoring system. A significant undertaking towards this is a mission to the L5 Sun-Earth Lagrange point. A complement of remote-sensing instruments and a suite of in-situ instruments is planned, with Phase A/B1 studies completed this year. The in-situ suite studied consisted of 5 instruments, a Magnetometer, a Solar Wind Monitor, a Medium Energy Particle Spectrometer, a Radiation Monitor and an X-ray Flux Monitor. This paper will discuss the Plasma Analyser (PLA), the suite’s solar wind monitor.
PLA is a top-hat type electrostatic analyser with enhanced performance features that include field-of-view steering and a variable geometric factor system. PLA draws on significant heritage from the SWA instrument suite currently on-board the Solar Orbiter mission, particularly the EAS sensor which uses similar performance enhancements over conventional top-hat analysers. The instrument is designed to measure ions at energies between 50 eV to 33 keV (~100 km/s to 2500 km/s) covering an FOV of 45° x 45° and an instrument sensitivity covering the range 0.1 to 150 particles/cm3.
Details of the instrument design will be presented and key challenges in meeting the measurement requirements and mission goals will be discussed. Currently, several technology developments activities are being pursued including optimisation of the optics and other sub-systems. Details of these will also be presented.
Results from an ongoing evaluation of the utility of an Electrostatic Analyser to investigate surface charging conditions at GEO will be presented, including an initial correlation with data from a LANL MPA sensor and a simple surface charging sensor. Use of this and similar sensors to investigate in-orbit spacecraft anomalies will be discussed.
The Sweeping Langmuir Probe (SLP) instrument on board the Pico-Satellite for Atmospheric and Space Science Observations (PICASSO) has been developed at the Royal Belgian Institute for Space Aeronomy. PICASSO, an ESA in-orbit demonstrator launched in September 2020, is a triple unit CubeSat flying at about 540 km altitude with 97 degrees inclination.
The SLP instrument includes four independent cylindrical probes. By sweeping the potential of a probe with respect to the plasma potential while measuring the current from this probe, the instrument acquires a current-voltage characteristic from which the electron density and temperature, ion density and spacecraft potential are retrieved. The instrument electronics box fit into an envelope of 104 x 98 x 25 mm. The mass of the whole instrument (electrics box together with the four probes, booms and harnesses) is just over 150 g.
Along the orbit of PICASSO, the plasma density is expected to fluctuate over a wide range, from about 1e8/m³ at high latitude up to 1e13/m³ at low/mid latitude. The electron temperature is expected to lie between approximately 1000 K and 10.000 K.
Given the high inclination of the orbit, the SLP instrument will allow a global monitoring of the ionosphere with a maximum spatial resolution of the order of a few hundred meters. The main goals are to study 1) the ionosphere-plasmasphere coupling, 2) the subauroral ionosphere and corresponding magnetospheric features, 3) auroral structures, 4) polar caps, and 5) ionospheric dynamics. Subject to successful commissioning, the first results of SLP will be presented at the workshop.
The instrument for SensIng electroMagnetic pulses on Cubesat (CubeSIM), currently in phase B at ONERA in the frame of the internal ONSAT-1 research project, aims to detect and measure the effects of electrostatic discharges induced by the plasma environment. The first mission envisioned to fly this instrument in SSO LEO orbit is called ChaRging On CubeSat (CROCUS). The targeted platform is a 2U cubesat from Centre Spatial Etudiant de l’Ecole Polytechnique (CSEP), currently in phase 0/A. CSEP and ONERA will be in charge of operating the spacecraft and exploiting the data, respectively. Ideally this mission would also fly the ESDEE active electron emitter under development at LATMOS. The challenge is to develop high sensitivity sensors and electronics with a limited impact for an integration on a 2U satellite (reduced power, volume and weight). The delivery of the CubeSIM flight model is expected by mid-2022.
The assessment of space environment effects is a challenge for cubesat missions because the high level expertise it requires is difficult to find within relatively small size development teams. In addition, national and international guidelines can be difficult to apply because they are intended to satellites much bigger than cubesat. These missions also lack flight feedbacks because this analysis requires information that is rarely monitored on-board. These transients have never been directly monitored on any European spacecraft and so the direct association of a particular ESD event and an operational anomaly has not been possible. ONERA, ESA and CNES are currently envisioning the development of new instruments to address questions such as how frequently ESDs occur, how robust existing protections of equipment are and how effective electrostatic charging prevention methods are.
CubeSIM is composed of a series of instruments dealing with electrostatic charging effects assessment. The FPGA-based TWIST instrument detects the occurrence of electrostatic discharges (ESD) sensed with antennae and lightweight probe sensors. SPARK regularly tests TWIST during quiet periods of time by mimicking ESDs transient waveforms deduced from ground test. MISTEEC increase the probability to get high level charging and to trigger ESDs by deploying panels made with materials with specific response to environmental plasma conditions. On the opposite, SCAPEE alleviates spacecraft charging by emitting electrons by passive field effect and tends to reduce the ESD occurrence.
We will present the experimental campaign conducted on a 2U cubesat mockup equipped with lab prototypes of TWIST and MISTEEC. The test setup has been mounted inside the JONAS vacuum plasma chamber (Onera test bench) and was electrically floating with respect to ground. The combination of a large-scale tank and floating connections avoids the electromagnetic disturbances induced by ground equipment. These conditions are strictly necessary to identify with precision the conditions leading to ESDs and to source the transient currents induced by an electron beam and a VUV source on a small satellite. About 100 ESDs have been generated and detected. We will show how these results are used to prepare the next prototypes and how, in the frame of a CNES R&D activity, they can be extrapolated to bigger platforms.
We will also quickly present the test results obtained on SCAPEE lab prototypes developed and manufactured in the frame of an ESA study. Their measured performances indicate that a few of these passive items could be sufficient to reduce drastically the negative charging of satellites undergoing severe environmental conditions, including GEO substorms. To meet the objectives of the CROCUS mission, it involves defining different CROCUS mission scenarii with separate / combined operating sequences for TWIST and SCAPEE.
The AMBER (Active Monitoring Box of Electrostatic Risk) charged particle detector on board the JASON-3 satellite orbiting at an altitude of 1336 km, was built in industry under the supervision of CNES, in collaboration with IRAP. Since February 2016, it allows the measurement of electrons and ions from 10 eV up to 27 keV along the satellite orbit. Its 180 ° field of view, divided into 4 sectors, points to the zenith. Various operating modes make it possible to acquire the energy spectra of ions and electrons in 64, 32 or 16 steps. This detector allows the measurement of auroral particles at high latitudes and also the charge of the satellite which develops when it is located in the shadow / penumbra of the Earth and is irradiated by intense fluxes of electrons of about ten keV. This presentation illustrates the main types of results provided by AMBER.
A heavy-ion beam monitor based on 3D NAND Flash memories was designed and tested with heavy ions at high energy and low LET. The capability of measuring fluence, angle, uniformity, and LET of impinging particles is discussed, together with the advantages over SRAM-based implementations. We propose ad-hoc algorithms for the extraction of the beam parameters, based only on user-mode commands. A validation of the system using low-LET ionizing particles impinging at different angles is presented. Experimental results show very good efficiency and accuracy.
Monitoring radiation dose levels in space is crucial, specially with the growing trend on using COTS in space applications. With such a goal, iC-Malaga / Sealicon Microsystems designs and produce integrated dosimeters on-chip, based in its proprietary FGDOS® technology, which allows truly passive (zero power) radiation dosimeter manufacturing in standard commercial CMOS technologies.
FGDOS® technology has enabled the design of highly-integrated, miniaturized and plug&play dosimetry systems, with FGD-02F and FGD-03F as first commercial product examples.
New FGDOS® developments oriented to space applications are specially focused on ultra-low power, and even smaller form factor to make its integration easier in smaller satellites, where size, power and also cost are key parameters.
As an example of these new developments, FGD-04D features 20uA at 2.5V supply (when active) in a 2x2mm DFN6 package. Having dual dose range in passive mode (10Gy and 50Gy) with 8-bit resolution, it is suitable for monitoring radiation levels in small sats for low earth orbit applications.
Extending the measurable dose range in passive mode (zero power) allows having the sensor powered-off most of the time without dose information loss. This translates not only in dramatically power consumption reduction but also in significant TID extension, since FGDOS® sensors are capable to withstand up to 2KGy when irradiated in fully passive mode.
Risk prediction in space radiation environments is challenging due to the mixed particle radiation field, especially of charged particle of high energy and charge (HZE) in galactic cosmic rays (GCR). It can be quantified in terms of probability for radiation exposure induced death (REID) from cancer. This approach is strongly based on a track structure of HZE ions determined density of ionization. Direct measurements of the track structure of ions or their prediction by measuring type, energy and fluence of HZE ions during space mission is challenging.
Another quantity, reflecting biological effect of radiation is dose equivalent, H. Microdosimetry is a very useful method to evaluate the dose equivalent of any mixed radiation field (photons, neutrons, ions), without prior knowledge of type of charged particles and their spectra. Regional microdosimetry is based on measuring of the stochastic ionizing energy deposited z, event by event, in a micron sized sensitive volume (SV) with similar dimensions to biological cells stochasticity of which also depends on size of SV and a track structure of ions.
The Centre for Medical Radiation Physics (CMRP), at the University of Wollongong in collaboration with SINTEF has successfully developed silicon on insulator (SOI) microdosimeters based on an array of 3D SVs of micron sizes integrated with readout electronics (also called µ+ probe) which is light weight (less than 0.25kg) and low power operation (less than 10V) [1].
The µ+ probe with “Mushroom” microdosimeter was used to verify various shielding materials of the International Space Station (ISS) wall in response to partial proton energy spectra (70-200)MeV of solar particle events (SPE), trapped and GCR at Paul Scherrer Institute (PSI) proton therapy facility in Switzerland and 400 MeV/u 16O, 400 MeV/u 20Ne, 490 MeV/u 28Si and 500 MeV/u 56Fe ions at Heavy Ion Medical Accelerator (HIMAC) in Chiba, Japan. Aluminium, Kevlar-epoxy, Nextel layers were used to mimic the ISS wall during the experiment. Microdosimetric spectra and related to them average quality factor (Q ̅) and the dose equivalent Hp(0.07) and Hp(10) per unit fluence as a measure of the radiation shielding efficiency were obtained experimentally upstream and downstream of the ISS wall [2]. Additionally, carbon fibre, polyethylene, Perspex with the same areal density of currently used aluminium were investigated for potential improvement of radiation shielding.
The µ+ probe was also able to measure accurately high lineal energy (up to 14MeV/m (Si)) of low energy ions including 7Li, 12C, 16O and 48Ti with ranges below 350 µm in silicon.
This study confirms that the portable µ+ probe with SOI microdosimeter is suitable for measurements the dose equivalent in mixed direct and secondary radiation fields produced by HZE ions typical of GCR and SEE in electronics prediction simultaneously. Good agreement of RBE predicted by SOI microdosimeter and from cell experiment will be presented.
The recent revival of space exploration implies an increased interest in space travels that are associated with many challenges and risks, mostly related to the ever-changing adverse space weather. Radiation of any types can be detrimental to both astronauts and the equipment on-board. The capability of monitoring radiation levels reliably in space is therefore becoming a critical aspect for space missions. Many existing radiation monitoring systems are bulky and require operation at high voltages with considerable power consumption. Other systems are often fabricated using off-the-shelf components, including Si diodes for radiation detection, but lack the necessary radiation tolerance to ensure sensor survival throughout the entire mission.
In the past decade, it was demonstrated that the "3D silicon sensor technology" provides unique solutions to the limitations of the existing technologies for radiation monitoring in space. 3D radiation detectors feature increased radiation hardness, due to their much shorter inter-electrode distance and increased freedom in electrode placement. The use of 3D sensor technology in radiation monitoring was first proposed by the Centre for Medical Radiation Physics (CMRP, Australia) in collaboration SINTEF (Norway) as a strategy to overcome many of the limitations of other sensor technologies. By creating micron-sized, cylindrical 3D sensitive volumes, this new type of sensor would be able to measure the microdosimetric spectra of mixed radiation environments and, through the theory of micro-dosimetry, return and estimation of the damage to biological tissue. This would allow to provide an accurate real-time reading of the risk posed to the crew by the radiation in space during the mission. 3D silicon processing also allows the integration of tissue-equivalent materials (e.g. PMMA) directly into the sensors, providing a more accurate representation of the interaction of radiation with the human body.
In this presentation we will discuss the idea behind 3D silicon microdosimeters, the challenges encountered during sensor fabrication and some of the results from recent sensor characterisation.
The Miniaturized Detector for Application in Space (MIDAS) is developed in response to the requirement of the European Space Agency for a device whose size, power consumption and radiation data output would increase the level of space-flight crew autonomy regarding operational decisions related to radiation hazards. It is based on fully depleted active Si pixel sensors for measuring LET and dose in Si and on neutron-gamma discriminating plastic scintillator read by Silicon Photomultiplier (SiPM) for measuring neutron energy spectra. The silicon pixel sensors are constructed in a standard CMOS process using high resistivity p-type substrate and deep n-type implants with the readout circuits in n and p-type wells on top of these implants. A first version has undergone electrical characterization and a second one is under construction. The plastic Scintillator/SiPM detector has been used to measure the spectrum of a Cf252 source. GEANT4 has been used to study the reconstruction of Galactic Cosmic Ray particle tracks from the Si-pixel detector information. Reconstructed tracks and energy depositions are used to predict the experimental Linear Energy Transfer (LET) and, finally, a conversion function to LET in water is determined. In addition, the device response in a typical radiation field inside a spacecraft has been studied. Particle identification and kinetic energy determination should be beneficial for the evaluation of dose equivalent using the NASA quality factors. For this reason, a preliminary study using artificial intelligence tools gave promising results both for particle identification and kinetic energy discrimination.
We present SpacepiX Radiation Monitor (SXRM), a novel 5-layer telescopic pixel detector with interleaved absorber layers based on new SpacePix2 ASIC. The SXRM is a low-power (<500mW average power consumption) compact radiation monitor designed for charged particle species and energy determination. It is designed for detection and identification of protons, electrons and heavy ions and it can provide basic functionality of a housekeeping radiation monitor with alert functionality capable of monitoring the space radiation environment. In addition, the SXRM supports operational modes of frame imaging, hit cluster reconstruction, particle track reconstruction and proton, e - and ion energy histogramming.
The SpacePix2 ASIC is a monolithic pixel detector manufactured in a 180 nm SoI technology with 30 micron deep sensitive region in the handling wafer and backside pulse digitization capability.
The ASIC contains a matrix of 64x64 pixels with a 60 micron pixel pitch. The dynamic range of the SpacePix2 ASIC was designed to be 2 ke- to 60 ke- in the pixel front-end and 300 ke- to 30 Me- in the sensor backside layer. Digitization of the signal is performed using fast 10-bit differential column ADCs. The manufacturing technology has been characterized for TID effects and SEU cross section has been measured using a shift register.
It is planned that the current technological demonstrator will be flown on the VZLUSAT2 mission at the end of 2020.
A miniaturized radiation monitor (MIRAM) has been developed by the Institute of Experimental and Applied Physics of the Czech Technical University in Prague together with their spin-off company ADVACAM s.r.o.. MIRAM combines a hybrid pixel detector of the Timepix3 technology with a 300 - 500 μm thick silicon sensor with a set of four diodes. It provides a real-time measurement of particle (namely electron, proton, ion) fluxes and a continuous measurements of the Total Ionizing Dose (TID). The pixel detector’s segmentation into a square matrix of 256 x 256 pixels (pixel pitch: 55 µm) allows an assignment of the different particle species using characteristic track features (dE/dX, curvature, …). The diodes provide particle resolving power for edge cases and create redundancy for the TID measurements. The dimensions of MIRAM are 8 x 5 x 3 cm with a total weight of 140 g. The average power consumption is below 1.5 W. In this contribution, we present the MIRAM design, methodology developed for on-board data analysis and measurements demonstrating the functionality of the device.
The highly integrated particle tracker consists of two Timepix3 ASIC-chip pixel detectors in close geometry and without shielding or collimators. The tracker is operated and readout by a space-designed radiation tolerant on-board payload computer (OPC) which also processes the extensive raw data produced by the pixel detectors (raw data rate up to 10 MB/s). Use of two detectors operated in sync with timing resolution 100 ns provide timing, spectral (energy loss) and enhanced tracking-directional resolving power. Wide field-of-view (nearly 2π) high angular resolution (< 1°) angular fluxes can be measured for energetic charged particles such as electrons above 1 MeV, protons above 5 MeV and ions above 50 MeV/u for omnidirectional fluxes up to E6 particles cm-2 s-1. Event-by-event processing and high-resolution spectral-tracking analysis enable to provide also selective (particle-event type discrimination) deposited energy distributions and LET spectra in wide range (0.1 – 500 keV/µm). Data products include characterization of the charged particle component of mixed-radiation fields with particle-type discrimination (electrons, protons, ions, X rays) and spectral/energy-loss range (low- and high-energy groups). Also detailed particle-type dose rates histograms can be generated. The whole payload (detector tracker + OPC) has a mass 150 g, power consumption 3 W, size < 9 cm and fits in 1/3 of a 1U Cubesat.
The Space Application of Timepix Radiation Monitor (SATRAM) is now in space for more than 7 years continuously measuring the radiation in Low Earth Orbit. It is attached to the Proba-V satellite, an Earth observing satellite of the European Space Agency (ESA) from an altitude of 820 km on a sun-synchronous orbit. The technology demonstration payload is based on the Timepix chip with a 300 μm thick silicon sensor with a pixel pitch 55 μm and 256 x 256 pixels. In a previous publication, a strategy to separate electrons, protons and ions in the data was presented. Since then, advances have been made in the separation of the different particle species through the use of neural networks. Results of the improved particle species identification will be presented together with the latest data on the measured in-orbit dose rates.
The ESA Next Generation Radiation Monitors (NGRM) are optimized for particle detection in harsh radiation environments among which we mention solar energetic particle fluxes and South Atlantic Anomaly trapped particles. These characteristics will be precious when solar energetic particle (SEP) events will be observed along the LISA orbit. However, particle monitors optimized for high particle flux monitoring in space, have small geometrical factors and, in general, do not allow for galactic cosmic-ray flux short-term variation monitoring. Forbush decreases and other, shorter non-recurrent galactic cosmic-ray variations generate a stochastic force noise associated with the test-mass charging process that might limit the LISA performance at low frequencies. We consider the possibility to add to the NGRM a third unit with high count-rate capability for protons (or protons and helium) above 70 MeV/n with a geometrical factor possibly larger than that of the particle detector flown on the LISA-PF S/C (9 cm**2 sr) to study, for instance, the evolution of Forbush decreases with an amplitudes down to 1.5%.
The first unit of the ESA Next Generation Radiation Monitor (NGRM) sensor - a pre-cursor of ESA distributed SWE Sensor System (D3S) – was switched on within the first hours after the launch of the European Data Relay System, Satellite-C (EDRS-C) on August, 2019. As a result, the NGRM unit has provided invaluable measurements during the GTO prior to its arrival at GEO 31 degrees East. The NGRM ground processor (GP), developed and integrated in the Payload Operation Data Centre, provides in real-time the processing chain from count-rate measurements, to a complete Level-0 dataset (count-rates with auxiliary data) and to Level-1 dataset (electron and proton fluxes). For the calculation of NGRM L1 datasets suitable methods were developed and applied utilizing the response functions of the NGRM unit as provided by the Paul Scherrer Institute. The derived flux products were evaluated using a series of third-party measurements made by space radiation detectors on-board EU Galileo satellites, Van Allen Probes, Himawari-8, Arase (ERG) and GOES-16. The first version of NGRM L1 datasets includes electron differential and integral fluxes within 0.18-2.9 MeV and 0.2-2 MeV respectively, while the energies of the flux levels for the differential proton fluxes covers the energy range 5-90 MeV. EDRS-C/NGRM datasets will become available at the Space Weather (SWE) data centre through suitable API and a dedicated webpage.
Acknowledgements: The work has been supported by the SSA P3-SWE-XXI NGRM Data Processing activity led by SPARC under ESA Contract No 4000127954/19/D/CT.
Notwithstanding notable improvements made in the last decades, the characterization of the near-Earth proton radiation environment is incomplete, with major uncertainties affecting the description of high-energy particles (>50 MeV) in the South Atlantic Anomaly (SAA) region. The Payload for Antimatter-Matter Exploration and Light Nuclei Astrophysics (PAMELA) satellite-borne experiment, operating between 2006 and 2014 at altitudes between 350 and 600 km, has recently provided first direct observations of geomagnetically trapped particles with energies up to a few GeV. Thanks to its high identification performance, it was able to carry out a precise and comprehensive measurement of particle fluxes in low-Earth orbit, including spectral, compositional, and angular information. PAMELA observations are fundamental not only for Space Weather purposes, but because they could help set important constraints on trapping and interaction processes in the Earth’s atmosphere and magnetosphere. Furthermore, they enable the testing and validation of current theoretical and empirical models of the inner radiation belt. In this contribution we report about an improved analysis of trapped protons detected in the SAA region between July 2006 and December 2009.
By now the Energetic Particle Telescope (EPT) on-board Proba-V (launched on 7th May 2013 onto a polar Low Earth Orbit of 820 km altitude) has provided quasi continuously more than 7 years of flux spectra data for electrons (0.5–8 MeV), protons (9.5–248 MeV) and α-particles (38–980 MeV) with a time resolution of 2 seconds. The data are transmitted to ground 3 times per day, where within several hours they are processed towards the following data products:
• daily flux spectra time series along the orbit (L1);
• weekly flux geographical maps;
• weekly averaged auroral electron energy spectra;
• weekly averaged SAA proton and helium energy spectra;
• yearly static radiation model of the three energetic particles, including flux time series on a regular B-L grid (L2);
• integral (“GOES-style”) electron, proton and helium fluxes will be available soon.
While the five first products mentioned here above are available at the ESA-SSA-SWE portal (ESA-SSA Space Weather, Expert Service Center Space Radiation) since October 2016 or later, the latter product will complete them by the end of 2020.
The mission operates far beyond of its nominal lifetime (2.5 years) offering a rather long contiguous dataset from one science-class instrument with rather stable parameters apart from a gain-loss accident of the front sensor in 2014, the instrument did not experience any significant technical parameter variation that would impact its flux measuring capabilities.
This presentation will give a summary on the EPT data products that are available at the ESA-SSA-SWE service centre, experience of this long-lasting mission, lessons learned, and suggestions for a future improved model of the instrument, and its routine operation.
Mission design is driven by human and spacecraft safety and accurate space radiation environment models are crucial. For space mission planning, flux predictions in the radiation belts are considered. For this, the AP-8 model for proton fluxes and AE-8 model for electron fluxes are used. They are empirical models of the omnidirectional trapped integral fluxes in Earth’s magnetosphere. The INTEGRAL Radiation Environment Monitor (IREM) is a particle detector that measures high-energy electrons and protons providing particle species and spectral information. It consists of three detectors in two detector head configurations. Here, the IREM is used to investigate the dependency of inner belt flux anisotropies environment (L < 2.5) on equatorial pitch angle distributions (B/B0 < 1.5). In specific, measured countrates are compared to countrates calculated from omnidirectional radiation belt model fluxes which are folded with the 3D instrument response functions and a sin^n pitch angle anisotropy model, where n is determined empirically.
Several satellite passages from December 2019 are investigated. In the comparison we find that AP-8 and AE-8 omnidirectional flux predictions (n=0) underestimate the measured countrates, which are about two times higher for channel C1 (for L>2) and channel S34 (all L). Introducing a sin^n (PA)anisotropy term, the predictions can be improved for both tested channels (S34 and C1). The anisotropy term changes the steepness of the varying countrates and shifts the predicted countrate evolution closer to the measured countrate evolution. The countrate magnitude is better approached for pitch angles closer to 90◦, as this increases the countrates.
In another approach, an anisotropy factor can be found by a fit through the measured countrates. For IREM, two periods of solar minima were explored (P1:2010-2014, P2:2018-2020). IREM fluxes are globally higher past 2018 than before. Equatorial, low L-shell countrates are higher in P1 than in P2. The peak countrates are observed at around 90 degrees for all channels. The anisotropy factor n is larger (n=8-9) for the lower energy channel (S34) for the L-shell 2 - 2.25 and lower (n=2-4) for the higher energy channels (C1-C3). In the higher L-shell region 2.25 < L < 2.5 the anisotropy factors for the lower energy channel (S34) is 6-7 and for the higher energy channel 2-6. Similar behaviour is found for the PROTEL data.
Accurate measurements of trapped energetic electron fluxes are of major importance for the monitoring of the radiation belts and for the characterization of space radiation environment. We present an inter-calibration analysis of the energetic electron flux measurements of MagEIS and REPT on-board the Radiation Belt Storm (or Van Allen) Probes (RBSP/VAP) using the measurements of the Extremely High-Energy Electron Experiment (XEP) on-board ERG/Arase mission. The performed analysis demonstrates a remarkable agreement between MagEIS and XEP data for electron energies $E<1$ MeV and suggests the use of re-scaling factors for the RBSP electron fluxes accounting for electron energies from 1 to 4 MeV. The application of the derived re-scaling factors is further supported from the ESA radiation monitor measurements of the Environmental Monitoring Unit (EMU) on-board GSAT0207 and from the Standard Radiation Monitor (SREM) on-board INTEGRAL mission. The demonstrated agreement and harmonization of electron flux measurements from the science-class missions RBSP (2012-2019) and Arase (ERG) (2017-2021) supports the use of these datasets as reference for the cross-calibration of electron flux measurements acquired from space radiation monitors on-board several satellite missions the orbits of which have crossed the near equatorial orbits of RBSP and Arase missions during within the outer belt during the last decade. The creation of harmonized datasets can contribute in the accuracy and reliability of both physical and engineering space radiation environment models.
HelMod is a Monte-Carlo model that reproduce solar modulation process during high and low solar activity periods, in the inner and outer heliosphere, at the Earth location and outside the ecliptic plane, making it suitable for both Earth orbit studies and deep space missions.
The main time dependent parameters are solar observables like the sunspot number, the tilt angle of neutral current sheet, the solar wind speed and the interplanetary magnetic field measured at Earth. The model includes both description of inner and outer Heliosphere. Outer boundary is evaluated with a time dependent procedure that agrees with in situ Voyagers measurements. The modulated spectra obtained with HelMod have been compared to high precision proton and nucleus galactic cosmic ray spectra, such as those provided by AMS-02 experiment, as well other solar modulation codes. Using historical records of such parameters it is possible to estimate forecast of solar activity for solar cycle 25 and 26. Present work will show the forecast procedure up to 22 years and accuracy of such predictions. Moreover, the same solar modulation models have been used to calculate the single event effect rate on a specific device both during low and high solar activity and results have been compared.