Workshop to discuss advances in the International Radiation Environment Near-Earth (IRENE) modelling initiative.
This workshop, which is a joint event organized by AE-9/AP-9/SPM Technical Team, European Space Agency, Space Applications & Research Consultancy and the Hellenic Space Center (local organization) - welcomes contributions on the following topics:
*Additional Topic: Amount of time given to these topics will depend on submissions
**Only the user perspectives session will support remote participation
Modelling of the Radiation Environment Near-Earth
The International Radiation Environment Near Earth Model (IRENE), formerly AE9/AP9/SPM, has provided the global satellite design community with enhanced specification capabilities over legacy models since 2012. Based on feedback from the community we have continued to improve and expand capabilities of the model suite. We have recently released updates to version 1.5 providing more features for capturing statistics such as variable timescale fluences and worst-case quantities. Pending updates will incorporate data sets including Pamela, PROBA-V, EPT, SREM, NASA’s Van Allen Probes (remaining data), and AFRL’s DSX. Version 2.0 will provide a new module-based architecture supporting additional hazard models (e.g., solar protons), new module-specific capabilities (e.g., local time dependence for plasma), and improved stitching between models. We will provide an update on development status and plans for future versions.
GREEN is a global model that combines local models developed at ONERA (IGE-2006, OPAL, OZONE, Slot,…) and AE/P8 for mission duration longer than 1 year. This model is solar-cycle dependent and can provide both mean and upper envelop fluxes, accounting for the dynamics between successive solar cycles. The objective of GREEN-NG, the new version of GREEN, is to replace the combination of local models and AE/P8 with reanalysis databases (see abstract from Nour Dahmen, ONERA). Like its predecessor, GREEN-NG will depend on the year within the solar cycle and will remain valid for missions exceeding one year in duration. This model, currently under development, leverages physics-based long-term reconstruction of the dynamics of the radiation belts to build an improved global model while preserving the well established quality of the different local models. GREEN-NG is currently under development with funding from CNES and ONERA.
The latest extension of the Solar Accumulated and Peak Proton and Heavy Ion Radiation Environment (SAPPHIRE) modelling suite is presented.
SAPPHIRE-2S is a probabilistic model for mission specification concerning Solar Energetic Particle (SEP) particle radiation.
It is based on the data of the latest version of the SEPEM Reference Dataset with the addition of newly curated data from the ACE, IMP8 and SOHO missions.
The model provides outputs for solar protons, electrons, and heavy ions in the 40 keV/nuc - 875 MeV/nuc range aiming to cover all aspects of SEP particle radiation.
The modelling is based on the established Virtual Timelines methodology of the previous SAPPHIRE versions with the addition of novel elements. These add
the capacity to provide physically and temporally coherent particle time-series as the base output allowing detailed SEP effects analysis and the coupling with other models.
We develop a radiation belt model by using probabilistic transport table that are calculated from test-particle simulations (GEMSIS-RBW). The parameters for the tables are L, background density constant along the field line, and chorus wave amplitude. The magnetic field is assumed to be the earth's dipole field. The two dimensional probabilistic table consists of the electron energy from 100 keV to 10 MeV and equatorial pitch angle from loss cone to 90 degrees. We have produced the probabilistic transport tables from the test-particle data sets before and after the scattering by single whistler chorus element. By referring the probabilistic transport tables, the model demonstrates the nonlinear and local scattering process. In this talk we briefly introduce the method and show the preliminary results.
A large proton belt enhancement occurred on 24 March 1991 following an interplanetary shock that impacted the dayside magnetopause at ~03:40 UT. Its formation was measured by the proton telescope aboard CRRES and attributed to the injection and inward transport of solar energetic particles (SEPs) by an azimuthally propagating electric field pulse induced by the shock’s compression of the magnetosphere. This led to an increase in the flux of high energy (>25MeV) protons by several orders of magnitude at L~2.5 which has been well-studied. However, a flux enhancement by up to one order of magnitude was also seen at 1-20MeV protons at L~2. Protons in this energy range pose a hazard to orbiting spacecraft as a major contributor to solar cell non-ionizing dose. The 1-20MeV enhancement cannot be explained by the inward transport of a solar proton source, because a newly-injected source population at the required energy would have a drift velocity too low to interact with the pulse. Instead, we hypothesize that the 1-20MeV enhancement was caused by the pulse redistributing already-trapped radiation belt protons. To test this hypothesis, we apply a novel method to model the change in phase space density during a shock event which utilizes reverse-time particle tracing simulations. Our results show that the 1-20MeV enhancement can be accounted for by internal redistribution as hypothesized. We thus identify a new mechanism for proton belt enhancements that does not depend on a SEP source and present a way to model it. This talk will present an overview of our work and discuss the wider implications for radiation environment modeling.
Modelling of the Radiation Environment Near-Earth
We investigate two significant challenges in climatological modeling: improving up on the local distributions at grid points in the models and modeling the spatio-temporal covariance structure. We propose the use of tabular local distributions, with extrapolation based on generalized gamma functions, with power-law transforms to represent the error distributions. The generalized gamma can represent either of the two widely-used distribution functions: a log-normal or a Weibull, depending on the parameters of the generalized gamma. The power law transform is a 2-parameter transform (linear in log flux) that allows a simple extension of the 2-parameter uncertainty covariance matrices already employed for Weibull and log-normal distributions. On the problem of spatio-temporal covariance, we describe a unified framework for modeling realistic, but constrained spatiotemporal covariances based on observed correlation coefficients, simulated coefficients, and a neural network that, by construction, produces valid covariances across the entire model domain. Together, these advances enable greater realism in surrogate time series models of the radiation environment.
We present a novel statistical methodology for developing a radiation belt specification model that provides short- to long-term flux averages for spacecraft mission profiles, accounting for variability due to launch date and space weather/climate conditions. For this, we use an existing reanalysis database constructed using a physics-based radiation belt model and data assimilation. We analyse its flux distributions as well as the space and time correlation functions, and build a representative statistical model of the reanalysis database. Using this statistical representation, we build an innovative specification model prototype which is fast and easy to use, but can effectively be used for mission profiles at all timescales.
This work received funding from the European Space Agency under ESA Contract 4000137689/22/NL/CRS.
To include topics such as:
Differences in Approaches
Validation of Models with Different Methods
Possible Convergence of Models for Usage
Radiation Data, Datasets and Databases of Relevance to Near-Earth Environment Modelling
The Geostationary Operational Environmental Satellite-R (GOES-R) series Magnetospheric Particle Sensor - Low Energy (MPS-Lo) instrument provides crucial measurements of 30 eV – 30 keV electrons and ions in the near-Earth space environment, essential for understanding and identifying spacecraft surface charging. Electrostatic discharge due to spacecraft charging is the leading cause of environmentally related anomalies on spacecraft and has caused the most serious anomalies which have resulted in the loss of mission. However, accurate interpretation of the MPS-Lo data requires meticulous instrument corrections. This presentation introduces a newly developed data product incorporating significantly improved corrections applied to historical GOES-R MPS-Lo observations along with in-development future improvements.
This enhanced product addresses multiple key challenges inherent in the original data, including:
This presentation will detail the methodologies employed in developing the improved data product and demonstrate how users can easily access this data product for scientific analysis. Furthermore, we will describe future improvements and releases currently in development.
The availability of this improved GOES-R MPS-Lo data product represents a significant advancement in space weather research and spacecraft anomaly investigation. We encourage the community to utilize this enhanced resource for a more accurate and comprehensive understanding of the near-Earth space environment.
The Space Environment In-Situ Suite (SEISS) on GOES-19 includes the Magnetospheric Particle Sensor – High Energy (MPS-HI), an instrument designed for measuring radiation belt electrons and protons that have energies responsible for charging of internal spacecraft elements, that can lead to disruptive or damaging electrostatic discharges. MPS-HI includes 5 electron telescopes and 5 proton telescopes, arranged in two North-to-South fans, looking radially away from Earth. Each electron telescope has 10 differential channels, 50 keV – 4 MeV, and two integral channels, >2 MeV and >4 MeV. Each proton telescope has 11 differential channels, 80 keV – 12 MeV. The most operationally important MPS-HI measurement is that of >2 MeV integral electron flux, which is used by the NOAA Space Weather Prediction Center for its geostationary radiation belt alerts. Accurate calibration of the MPS-HI sensor is important in maintaining continuity of the radiation belt measurements used for both scientific and operational purposes. We present the steps taken for the calibration of the GOES-19 SEISS MPS-HI instrument, including a comparison with the same instrument on GOES-16.
We discuss the current status of the combined dataset from the Energetic Particle Composition and Thermal Plasma Suite (RBSP-ECT) on Van Allen Probes. The dataset combines electron measurements from the HOPE, MagEIS and REPT instruments, providing almost 7 years of observations of the inner and outer radiation belts with energies from a few eV up to 10s MeV. Here, we will discuss the cross-calibration effort that went into the combined dataset and potential for integration into a future version of the IRENE model. In addition, we will also briefly discuss additional datasets, including the LEO REACH constellation of dosimeters and potential applications for ongoing modeling and validation efforts.
Discussion on access, usefulness and further exploitation of radiation data near-Earth.
Radiation Data, Datasets and Databases of Relevance to Near-Earth Environment Modelling
The first Norwegian Radiation Monitor (NORM) sensor unit, flying aboard the Arctic Satellite Broadband Mission (ASBM), provides critical information on the space radiation environment along its three-apogee (TAP), 16-hour highly elliptical orbit (HEO). This work reviews the first year of NORM measurements, presenting the first detailed evaluation, analysis, and validation of radiation environment measurements along the TAP orbit, specifically focusing on trapped electrons and solar particle radiation. A series of validation studies demonstrate the inter-consistency of NORM measurements relative to the unit’s on-ground and numerical calibration, as well as with measurements from other radiation monitors. Additionally, comparisons between NORM flux measurements and electron radiation belt specification models are presented. Results show that NORM provides high-quality, high-resolution measurements of varying electron fluxes within the 0.4–6 MeV energy range as the satellite crosses the outer electron belt. Furthermore, NORM provides qualitative measurements of solar energetic protons within the 10–90 MeV energy range. ASBM/NORM datasets are an invaluable asset for developing and validating space radiation environment models.
The satellite PROBA-V with the Energetic Particle Telescope (EPT) onboard, was launched on 7 May 2013 onto a polar Low Earth Orbit of 820 km altitude. Almost continuously in operation, EPT has provided 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. Hence, the EPT data set covers already one full solar cycle period and continues its measurements for already one more year, thus starts for spanning the time series over one more solar cycle. EPT did witness the Saint-Patrick storm (March 2015) and the exceptional September 2017 solar energetic particle event of the falling phase of solar cycle 24, as well as the minimum activity around 2020 when outer belt electrons did nearly vanish, but also their great coming back in May 2024. The presentation will give an overview of the most remarkable measurements of the instrument till today, as well as features and caveats of the dataset
The CREDANCE instrument suite flew on the DSX satellite between August 2019 and May 2021. CREDANCE monitored charging currents through a SURF detector, >40 MeV protons via a proton telescope, total ionising dose with two RADFETs, and LET spectra with an ion telescope. The data will be briefly reviewed before comparing the observations to predictions obtained with IRENE models. Comparisons will be presented for charging currents, proton fluxes, and total ionising dose, and the self-consistency of the results will be discussed.
A Standard Radiation Environment Monitor (SREM) unit will be part of the European Radiation Sensors Array (ERSA) payload for the Lunar Gateway. This SREM unit will provide measurements of the lunar particle radiation environment, which is primarily dominated by Solar Energetic Particle (SEP) events and Galactic Cosmic Rays (GCRs). We present the reanalysis and creation of new datasets of SREM measurements from the INTEGRAL, PLANCK, and HERSCHEL missions. We have adapted and applied an existing artificial intelligence unfolding method (GenCORUM) to derive high quality particle fluxes during SEP events, and it is shown that we can successfully and concurrently derive solar proton and solar electron fluxes. Solar protons are resolved at a much higher energy than previously possible, up to ~1 GeV, while solar electrons, which have not been previously resolved, are derived in the energy range of 0.5 MeV - 4 MeV. Additionally, we show that SREM directly measures GCR particle fluxes, which fully determine its background levels with a non-negligible contribution from heavy ions (Z≥2). Using appropriate GCR models we have also resolved GCR fluxes directly from SREM measurements covering a large energy range from 10 MeV/nuc to 100 GeV/nuc. Finally we present elements on the new historical datasets created and the real-time applicability of our approach for ERSA/SREM. Successful validations of our results are shown by comparisons with the SEPEM RDS proton dataset, electron data from ACE/EPAM, and SOHO/EPHIN, as well as established models and data for GCRs.
The 3D Energetic Electron Spectrometer (3DEES) has been developed as a science-class instrument that is optimized for the measurement of angle resolved electron spectra in the energy range 0.1 - 10 MeV in the Earth’s radiation belts. The demonstrator model of the instrument (measuring simultaneously from 6 directions) was launched on board PROBA-3 on 2024/12/05 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 is covering parts of the inner belt, outer belt and mostly the border of the magnetosphere. Thus, the primary objective of the 3DEES mission is to give an accurate picture of the high-energy electron population in the magnetosphere for scientific studies of their acceleration and loss processes, through measure of angle resolved energy spectra of electrons, which also constitute boundary conditions to advanced physics models. In addition the mission targets to deliver Space Weather data for now- and forecasting activities. The presentation will explain details on the 3DEES mission onboard PROBA-3 and present the first data measured by the instrument after the launch.
Radiation Data, Datasets and Databases of Relevance to Near-Earth Environment Modelling
Discussion on access, usefulness and further exploitation of radiation data near-Earth and on gaps in of radiation datasets near-Earth.
Panel Discussion including Industry partners/end users
Existing, upcoming and proposed missions of relevance to modelling of the radiation environment
Monitoring of the Earth's and Sun's environment is an essential task for the now- and forecasting of Space Weather and the modeling of interactions between the Sun and the Earth. For this reason, ESA is implementing the Distributed Space Weather Sensor System to observe the effects of solar activity from various orbits in Earth's vicinity.
In particular, radiation belt monitoring data from a wide variety of locations in the magnetosphere is persistently requested by space weather modelers and service providers. In order to cover the Earth’s radiation belts a wide variation in altitude at low inclination, or more precisely in magnetic field characteristics, is needed. Therefore a mission in a geostationary-transfer orbit would be ideal to obtain the requested measurements, namely the particle fluxes of highly energetic electrons and protons together with the vector measurements of the magnetic field and the plasma characteristics.
The Space Weather Orbital Radiation Detector (SWORD) mission was first studied in ESA's Concurrent Design Facility and currently industrial pre-Phase A studies are ongoing. The baseline mission scenario foresees two satellites in a GTO-like orbit slowly rotating to capture the full pitch angle distribution of energetic particles in the inner and outer radiation belt. The mission drivers are measurement optimisation as well as the data availability, continuity and timeliness.
The presentation will introduce the mission concept, current design and roadmap.
ReTiMo is a mission concept of a CubeSat nanosatellite equipped with novel sensors and instruments in order to characterize in near-real time Space Weather threats to satellites that are becoming part of the critical infrastructure in modern life. ReTiMo will achieve this by measuring scientific parameters relating to Space Weather conditions, as well as engineering parameters that quantify the degradation and anomalous behavior of spacecraft hardware caused by Space Weather. In particular, ReTiMo will provide near-real time information on Single Event Effects on electronics of various damage thresholds, together with fluxes of damaging energetic protons that can be either trapped in the radiation belts or impinging upon near Earth space from the Sun during large solar eruptions. ReTiMo will also measure spacecraft charging due to auroral precipitating electrons, field-aligned currents that correlate with enhanced surface charging, and the degradation of solar cell parameters caused by energetic particles. In this talk, we will present the instrumentation, measurement principles and mission parameters of the ReTiMo mission concept, and we will discuss aspects of mission optimization, complementarity with existing measurements and applicability to various orbits.
Opportunity to brainstorm about other upcoming missions or concepts that would be of interest.
Radiation Data, Datasets and Databases of Relevance to Near-Earth Environment Modelling
The High Energy Proton Instrument (HEPI) is a compact Cherenkov telescope under development at the Surrey Space Centre, with funding from ESA and UKSA. It is aimed at measurements of the > 300 MeV protons of SEP events but will cover the trapped and the GCR protons also. A breadboard implementation has been successfully completed an extensive test campaign at TRIUMF with various proton beam energies and intensities. All these works have resulted in two publications. In this talk, I will summarise the current status and main achievements of the development so far and outline our future development plan.
The interplanetary particle radiation environment is primarily characterized by cosmic rays and solar energetic particle events. Recently, a novel specification solar particle radiation model was developed with the aim to expand upon the ESA Solar Accumulated and Peak Proton and Heavy Ion Radiation Environment (SAPPHIRE) model. The SAPPHIRE-2S model uses the SEPEM Reference Dataset (RDS) and the SEPEM Reference Event List (REL) which were developed primarily for implementation in the SAPPHIRE model. In the frame of the FIRESPELL project, and in order to continue the development of the SAPPHIRE-2S model, we have utilised a number of interplanetary particle datasets to include SEP electron radiation, an important component of SEP events which has not been extensively modelled, as well as low energy protons and helium (approximately in the 0.04-5 MeV energy range). These particles at these energies are relevant to radiation effects and mission specification and in this work we present the data and appropriate pre-processing methods (despiking, cross-calibration, etc.) employed. The final product is a homogeneous dataset for the new electron and low-energy ion component of SEP radiation covering all SEP events defined in the REL spanning the years 1974-2017.
This work has received funding from the European Space Agency under the "Particle Radiation Modelling for Interplanetary Missions Extending to Low Energies (FIRESPELL)" activity under ESA Contract No 4000142510/23/NL/CRS.
Spacecraft design has consistently relied on specification models to provide estimates of radiation exposure ranges to develop the necessary passive protections. As they mainly rely on in-situ data, the current standard models can suffer from data gaps and bias. Fortunately, climate reanalysis offers a viable alternative, enabling the construction of continuous and reliable cartographies of the radiation belt dynamics over extended periods. This is achieved through the assimilation of historical observations with theoretical radiation belt models. In this presentation, we will delve into the climate reanalysis operation of trapped electrons and protons over the last decade, using the Salammbô code and conducted within the framework of the GLORAB project.
This work received funding from the European Space Agency under ESA Contract 4000137689/22/NL/CRS.
Discussion on useful databases and ways they might be augmented/improved.
Tools into which models are incorporated for use by scientists and industry
The SPace ENVironment Information System (SPENVIS) is a web-based interface providing access to a wide range of space environment and effects models for mission analysis, planning, education, and research. Under ESA contract a new SPENVIS system (SPENVIS-5) is developed, built on ESA’s Network of Models (NoM) to enhance modularity and interoperability.
As part of a set of models to simulate the near-Earth radiation environment, the IRENE model (version 1.58) has been integrated into NoM and SPENVIS-5. To improve the usability of IRENE, additional features have been introduced at the SPENVIS layer. In this presentation we demonstrate how IRENE operates within NoM and illustrate the enhancements implemented in SPENVIS-5, highlighting how they streamline the user interaction with the model and the applied analysis.
We will present the impact of IRENE models on the Total Ionizing Dose (TID) [1], on Single Event Effect (SEE) rate [1] and on solar cell degradation [2], with respect to historical models such as AE8max/AP8min, MEOv2 and IGE2006, widely used in the space industry.
OMERE freeware, downloaded by a large amount of people all around the world, was first used to compute spectrum from IRENE and historical models, for different missions, and then used to calculate the induced effects in terms of SEE rate for some components and solar cell degradation for a classical 3G30 cell. For the TID calculation, FASTRAD software was used, allowing to consider a 3D realistic geometry of different units and components.
[1] “Impact of the use of new environment models on the project specification” – R&T study with CNES - 2022
[2] “Benchmarking of the SADC model” – R&T study with CNES - 2023
There is a need to be able to produce survivability specifications for the natural radiation environment and the resulting effects for a spacecraft mission. Over the years more environment models have become available for the various sources of the natural radiation environment. These sources include Earth’s atmosphere, trapped radiation, solar plasma, solar energetic particles, and galactic cosmic rays. These host of models have been developed with the goal to predict the state of these sources at any point in space at any given time. There are also a wide range of radiation transport modeling options to choose from to calculate the particle and energy spectra that arrive at the regions of the spacecraft where effects are needed to be known for proper part, material and shielding selections. The fidelity of radiation transport that is required can vary greatly depending on mission parameters and requirements. The more detailed transport can be costly in terms of time and computation resources and if such detail isn’t needed then more approximated and faster options can be chosen. The resulting environment at the regions of interest are then used as inputs to response functions and effects models to determine the kinds of effects that can be expected in mission. A spacecraft mission planner desires to have the results from the chain of models for environmental, radiation transport and effects that are thought to provide the required accuracy while minimizing the resources needed for the assessment for that particular spacecraft mission. It is also desirable to be able to easily add in new models as they become available and to compare to legacy specifications that were created using older model tool chains. The Space Environment Effects Digital Laboratory is under development at Aerospace that will allow for ‘a la carte’ model selection that permits any included models to be chained together into an integrated package, that will then produce concise templated reports with data and graphs of the environment and effects to spacecraft components for a specified mission or comparing various notional missions for a given spacecraft geometry.
Discussion of the previous talks and issues with implementation and usability of models within tools intended for spacecraft design in contrast to scientific investigations.