The objectives, instrumentation, methods and data leading up to launch of the NASA Living With a Star (LWS) Space Environment Testbed (SET) payload onboard the Air Force Research Laboratory ...Demonstration and Science Experiments (DSX) spacecraft are described. The experiments characterize the space radiation environment and how it affects hardware performance. The payload consists of a compact space weather instrument and a carrier containing four board experiments.
Satellite charging is one of the most important risks for satellites on orbit. Satellite charging can lead to an electrostatic discharge resulting in component damage, phantom commands, and loss of ...service and in exceptional cases total satellite loss. Here we construct a realistic worst case for a fast solar wind stream event lasting 5 days or more and use a physical model to calculate the maximum electron flux greater than 2 MeV for geostationary orbit. We find that the flux tends toward a value of 106 cm−2·s−1·sr−1 after 5 days and remains high for another 5 days. The resulting flux is comparable to a 1 in 150‐year event found from an independent statistical analysis of electron data. Approximately 2.5 mm of Al shielding would be required to reduce the internal charging current to below the National Aeronautics and Space Administration‐recommended guidelines, much more than is currently used. Thus, we would expect many satellites to report electrostatic discharge anomalies during such an event with a strong likelihood of service outage and total satellite loss. We conclude that satellites at geostationary orbit are more likely to be at risk from fast solar wind stream event than a Carrington‐type storm.
Key Points
We calculate the electron flux at geostationary orbit for a realistic worst‐case event
Approximately 2.4 mm of Al is required to shield electronic components
Satellites at geostationary orbit are more at risk from a fast solar wind stream event than a Carrington‐type event
X-ray source populations in the Galactic plane Hands, A. D. P.; Warwick, R. S.; Watson, M. G. ...
Monthly notices of the Royal Astronomical Society,
06/2004, Letnik:
351, Številka:
1
Journal Article
High‐energy trapped electrons in the Van Allen belts pose a threat to the survivability of orbiting spacecraft. Two key radiation effects are total ionizing dose and displacement damage dose in ...components and materials, both of which cause cumulative and largely irreversible damage. During an extreme space weather event, trapped electron fluxes in the Van Allen belts can increase by several orders of magnitude in intensity, leading to an enhanced risk of satellite failure. We use extreme environments generated by modeling and statistical analyses to estimate the consequences for satellites in terms of the radiation effects described above. A worst‐case event could lead to significant losses in power generating capability—up to almost 8%—and cause up to four years' worth of ionizing dose degradation, leading to component damage and a life‐shortening effect on satellites. The consequences of such losses are hugely significant given our increasing reliance on satellites for a vast array of services, including communication, navigation, defense, and critical infrastructure.
Plain Language Summary
Satellites are exposed to a variety of sources of potentially damaging space radiation. One of the most important of these is the population of high‐energy electrons that lies trapped by the Earth's magnetic field—the so‐called Van Allen belts. During an extreme space weather event, trapped electron fluxes in the Van Allen belts can increase by several orders of magnitude in intensity, leading to an enhanced risk of satellite damage. One example of this damage is degradation in the power‐generating capability of satellite solar panels. The threat from space weather in this context has hitherto been associated with solar proton events, that is, bursts of energetic protons that are sporadically emitted from the Sun. However, our analysis shows that enhancements in the Van Allen belt electron population can exceed the solar proton threat, which has implications for the protection of satellites from such phenomena. It is essential that sufficiently robust engineering design measures are put in place, in order to ensure the future reliability of satellite technology, on which our society is increasingly reliant.
Key Points
Extreme space radiation environments are used to calculate cumulative engineering effects on spacecraft in geostationary and medium Earth orbits
Extreme enhancements to trapped electrons in the Van Allen belts cause more cumulative damage than extreme solar energetic particle events
A temporary enhancement in trapped electron intensity could result in up to 7.6% degradation of solar cell power capacity
We use electron flux derived from the environment monitoring unit "(EMU)-SURF" current monitor on board a Galileo Global Navigation Satellite System (GNSS) constellation satellite to modify and ...update the model of outer belt electrons for dielectric internal charging (MOBE-DIC). We describe how this data set, together with data from similar current-measuring instruments on Van Allen Probes, Giove-A, and STRV1d, are used to improve and expand the model. We have extended the spatial range to include the inner belt, exploited EMU data to widen the energy range for the electron spectrum, updated the statistical analysis of flux variation using a data set double the size used for the original model, and established a new and independent latitude function that yields improved agreement in medium earth orbit compared to the original model. The model is entirely characterized by a set of equations and parameters that produce fluxes as a function of magnetic coordinates at three distinct statistical levels.
Significant increases to the atmospheric radiation environment are recorded by a network of ground level neutron monitors as ground level enhancements (GLEs). These space weather phenomena pose a ...risk to aviation via single event effects in aircraft electronics and ionizing dose to passengers and crew. Under the UK Space Weather Instrumentation, Measurement, Modeling and Risk programme, we have developed a new model to provide nowcasts of the aviation radiation environment, including both the galactic cosmic ray (GCR) background and during GLE events. The Model for Atmospheric Ionising Radiation Effects (MAIRE+) uses multiple data sources to characterize primary GCR and GLE particle spectra and combines these with precalculated geomagnetic and atmospheric response matrices to predict particle fluxes from ground level to 20 km altitude across the entire globe. Two European neutron monitors (located at Oulu in Finland and Dourbes in Belgium) are used as the primary indicators of GLE intensity in order to maximize accuracy over UK airspace. Outputs from MAIRE+ for the historical GLEs in September and October 1989 are compared to recalibrated empirical data from a solid‐state detector that was carried on Concorde in that period. The model will be hosted in the UK and will provide additional capability to the Met Office Space Weather Operations Center (MOSWOC).
Plain Language Summary
Ionizing radiation in the atmosphere is primarily caused by galactic cosmic rays (GCR) interacting with the upper atmosphere, creating showers of secondary radiation. At aviation altitudes the radiation environment is hundreds of times more intense than that experienced at the ground level. This relatively stable background level of radiation is punctuated by space weather events called ground level enhancements (GLEs), when energetic solar protons arrive at Earth and lead to elevated atmospheric radiation levels that can be orders of magnitude greater than background levels. Under the UK Space Weather Instrumentation, Measurement, Modeling and Risk programme, we have developed a new model to provide nowcasts of the aviation radiation environment, including both the GCR background and during GLE events. Through our Model for Atmospheric Ionising Radiation Effects, we show how data from ground level neutron monitors can be used to characterize the atmospheric radiation environment from ground level to 20 km altitude across the entire globe.
Key Points
The new Model for Atmospheric Ionising Radiation Effects (MAIRE+) is presented
MAIRE+ uses neutron monitor data, sunspot number, Kp, and geostationary proton flux to nowcast the aviation radiation environment
Model outputs are compared to data from a solid‐state detector carried on board Concorde during ground level enhancements in 1989
Ground level enhancements (GLEs) are space weather events that pose a potential hazard to the aviation environment through single event effects in avionics and increased dose to passengers and crew. ...The existing ground level neutron monitoring network provides continuous and well‐characterized measurements of the radiation environment. However, there are only a few dozen active stations worldwide, and there has not been a UK‐based station for several decades. Much smaller neutron detectors are increasingly deployed throughout the world with the purpose of using secondary neutrons from cosmic rays to monitor local soil moisture conditions (COSMOS). Space weather signals from GLEs and Forbush decreases have been identified in COSMOS data. Monte Carlo simulations of atmospheric radiation propagation show that a single COSMOS detector is sufficient to detect the signal of a medium‐strength (10%–100% increase above background) GLE at high statistical significance, including at fine temporal resolution. Use of fine temporal resolution would also provide a capability to detect Terrestrial Gamma Ray Flashes (via secondary neutrons) which are produced by certain lightning discharges and which can provide a hazard to aircraft, particularly in tropical regions. We also show how the COsmic‐ray Soil Moisture Observing System‐UK detector network could be used to provide warnings at the International Civil Aviation Organization “Moderate” and “Severe” dose rate thresholds at aviation altitudes, and how multiple‐detector hubs situated at strategic UK locations could detect a small GLE at high statistical significance and infer crucial information on the nature of the primary spectrum.
Plain Language Summary
Space weather events can lead to significant increases in the intensity of the atmospheric radiation environment, including at ground level. These ground level enhancements (GLEs) have been detected by a global network of neutron monitors for over 70 years. However, these instruments are expensive to construct and maintain. Only a few dozen are currently active, with no station located in the United Kingdom for several decades. As part of an effort to improve the resilience of UK infrastructure to space weather, we have studied the possibility of using alternative detectors to supplement neutron monitor measurements. COSMOS detector networks in the United Kingdom, North America, Australia and elsewhere use variations in ground level neutron flux to infer information on local soil moisture conditions for hydrological applications. We show that these same detectors could be dual‐purposed to provide information on GLEs that would complement the global neutron monitor network by providing much finer spatial resolution and, therefore, a highly localized warning system for space weather threats to aviation.
Key Points
Data from cosmic ray neutron sensor (CRNS) networks have been reprocessed and analyzed in the novel context of Space Weather
Ground level enhancements from solar cycle 24 present weak signals in the data
Monte Carlo simulations show such CRNS networks are suitable for dual‐purposing as space weather detectors
Summary
Background
Data on the epidemiological impact and clinical characteristics of chronic hand eczema in Southern Europe are lacking.
Objectives
To estimate the prevalence of chronic hand eczema ...in its different stages of severity and refractoriness to standard therapy in patients accessing Italian dermatological reference centres, and to evaluate sociodemographic and clinical factors associated with each stage.
Methods
A cross‐sectional multicentre study was conducted. Adult patients with hand eczema, consecutively accessing 14 centres over a 6‐month period, were enrolled. Patients were classified according to disease duration, severity and response to standard therapy with potent topical corticosteroids. Logistical regression was performed to investigate the relationship between sociodemographic and clinical data with different stages of eczema.
Results
The total number of participants was 981. Hand eczema was chronic in 83·5% of patients; 21·3% had severe eczema, with 62·0% of these patients refractory to standard therapy. Food processing and related work, the health professions, craft and related trade works (building, plumbing, electrical), hairdressing/beauty and handicraft work were most frequently associated with chronic hand eczema. Severe chronic hand eczema was more likely to be seen in men, older patients and those with less education. Severe and refractory hand eczema was also more likely among the unemployed and patients with allergic rhinitis and/or atopic dermatitis.
Conclusions
Chronic hand eczema is frequent among patients with hand eczema accessing dermatology centres. Many patients were severe and refractory to standard therapy. The appropriate identification of hand eczema is the first step in implementing effective and efficient treatments.
What's already known about this topic?
Hand eczema is a frequent dermatological disorder that can develop into a chronic, severe and refractory stage.
What does this study add?
Chronic hand eczema is common among patients accessing dermatological reference centres in Italy. One‐fifth are severe and one‐tenth are also refractory to standard therapy.
Severe chronic hand eczema is more common among men, patients aged 41–50 years and those with less education. Severe and refractory chronic hand eczema is also associated with atopic dermatitis and the unemployed.
Relativistic electrons can penetrate spacecraft shielding and can damage satellite components. Spacecraft in medium Earth orbit pass through the heart of the outer radiation belt and may be exposed ...to large fluxes of relativistic electrons, particularly during extreme space weather events. In this study we perform an extreme value analysis of the daily average internal charging currents at three different shielding depths in medium Earth orbit as a function of L∗ and along the orbit path. We use data from the SURF instrument on board the European Space Agency's Giove‐A spacecraft from December 2005 to January 2016. The top, middle, and bottom plates of this instrument respond to electrons with energies >500 keV, >700 keV, and >1.1 MeV, respectively. The 1 in 10 year daily average top plate current decreases with increasing L∗ ranging from 1.0 pA cm−2 at L∗=4.75 to 0.03 pA cm−2 at L∗=7.0. The 1 in 100 year daily average top plate current is a factor of 1.2 to 1.8 larger than the corresponding 1 in 10 year current. The 1 in 10 year daily average middle and bottom plate currents also decrease with increasing L∗ ranging from 0.4 pA cm−2 at L∗=4.75 to 0.01 pA cm−2 at L∗=7.0. The 1 in 100 year daily average middle and bottom plate currents are a factor of 1.2 to 2.7 larger than the corresponding 1 in 10 year currents. Averaged along the orbit path the 1 in 10 year daily average top, middle, and bottom plate currents are 0.22, 0.094, and 0.094 pA cm−2, respectively.
Key Points
We determine the 1 in 10, 1 in 50, and 1 in 100 year SURF plate currents in medium Earth orbit
The 1 in 10 year middle plate current decreases with increasing L∗ ranging from 0.4 pA/cm2 at L∗=4.75 to 0.01 pA/cm2 at L∗=7.0
The 1 in 100 year middle plate current is a factor of 1.2 to 2.7 larger than the corresponding 1 in 10 year event
Historically, gathering data on atmospheric radiation levels during solar particle events has been difficult, as there is little or no time warning of events. Being able to accurately quantify ...radiation levels within the atmosphere during solar events is of significance to the aviation industry, as described in the International Civil Aviation Organization's (ICAO) Space Weather manual. Particularly during a large ground‐level enhancement (GLE) where the ionizing dose to passengers and crew can exceed the recommended general public annual dose limits, set by the International Commission for Radiological Protection (Barlett, Beck, Bilski, Bottollier‐Depois, & Lindborg, 2004, https://doi.org/10.1093/rpd/nch232), in a single flight. The Smart Atmospheric Ionizing RAdiation (SAIRA) Monitoring Network is a new system of handheld radiation detectors that can be carried on aircraft to monitor and record atmospheric radiation levels. The system operates via citizen science volunteers, who record radiation data as they travel for normal purposes. Over 30 flights have been conducted with volunteers to demonstrate that a citizen science network is possible. Volunteers have used a new Android application to record and upload data to a central server to form a database of flight measurements. The demonstration has shown that there is a willingness in public volunteers to use radiation detectors and engage in science outreach. A fully developed system will ideally provide the capability to quantify radiation levels during a solar particle event or ground‐level enhancement and the data can be used by relevant organizations to minimize potential risks.
Key Points
A new method of capturing atmospheric radiation data from ground‐level enhancements (GLEs)
Demonstrates the use of a citizen science data gathering system, using handheld silicon radiation detectors as carry‐on luggage items on commercial aircraft
The system operates via USB‐connected smartphones, running a new application on Android OS, to record and upload data to a centralized server
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