Michel Kruglanski

A low altitude trapped proton model for solar minimum conditions based on SAMPEX/PET data

We present a low altitude (below about 600 km) trapped proton model for solar minimum conditions (1994-1995), based on measurements made by the Proton/Electron Telescope onboard the SAMPEX satellite. Substantial differences are found with the low altitude part of the AP-8 MIN model: low energy fluxes appear to be overestimated by AP-8 MIN, while the new model predicts higher fluxes than AP-8 MIN for energies above about 30 MeV.

Last upgrades and development of the space environment information system (SPENVIS)

The ESA operational software SPENVIS allows rapid analysis of the hazardous space environment and its effects. This news presents the upgrades of existing models and additional new models planned for the release of June 2009.

Services for GNSS users within the ESA Space Situational Awareness Space Weather Service Network

Ionospheric Space Weather can adversely degrade the performance of radio systems in communication, space based navigation and remote sensing. Navigation signals transmitted by Global Navigation Satellite Systems (GNSS) are delayed, refracted and diffracted by the highly variable ionosphere affecting the accuracy, availability, continuity and integrity of GNSS signals which can be crucial in safety of life and precise positioning applications. Therefore detection, monitoring and prediction of ionospheric effects are important for mitigating such impact. In the frame of its Space Situational Awareness (SSA) programme, the European Space Agency (ESA) is establishing a Space Weather Service Network to support end-users, in a wide range of affected sectors, in mitigating the effects of space weather on their systems, reducing costs and improving reliability. In this paper we present an overview of the current status of the network, the targeted end user groups and Expert Service Centers (ESCs). Focusing on the ESC for Ionospheric Weather (I-ESC), we report on the currently available products and tools as well as on the recent and ongoing activities in expanding the network for this domain.

Proton Spectra Detected by the Proton Switches on the CRRES Satellite

A thorough detector characterization method is described and applied to analyze the data from the proton switches flown on the Combined Release and Radiation Effects Satellite (CRRES). The results are compared with the CRRESPRO model based on observations of the proton telescope (PROTEL), which was on board the same satellite. A general good agreement is observed at positions where the flux of high energy protons is low. In regions of harder proton spectra, the CRRESPRO fluxes are higher than those deduced from the proton switches data. One possible explanation for this discrepancy may be that high energy protons penetrating into the PROTEL detector ly accounted for.

Statistical Analysis of SAMPEX PET Proton Measurements

We present a statistical study of the distributions of proton counts from the Proton–Electron Telescope aboard the low-altitude polar satellite SAMPEX. Our statistical analysis shows that histograms of observed proton counts are generally distributed according to Poisson distributions but are sometimes quite different. The observed departures from Poisson distributions can be attributed to variations of the average flux or to the non-constancy of the detector lifetimes.

Services for Space Mission support within the ESA Space Situational Awareness Space Weather Service Network.

Spacecraft operations are by nature complex and every satellites operational environment poses a range of potential risks, often a unique combination for a given orbit. The implications of interruptions of operations, data transfer and service provision, are serious, both in terms of cost and capability, thus it is imperative to mitigate against all operational risks to the fullest extent possible. In the frame of its Space Situational Awareness (SSA) programme, the European Space Agency (ESA) is establishing a Space Weather Service Network to support end-users, in a wide range of affected sectors, in mitigating the effects of space weather on their systems, reducing costs and improving reliability. This service network is currently in a test and validation phase and encourages user engagement and feedback. The network is organised around five Expert Service Centres (ESCs) focusing on Solar Weather, Heliospheric Weather, Space Radiation Environment, Ionospheric Weather and Geomagnetic Conditions. Each ESC is connecting different expert groups, federating their space weather products, and ensuring the quality and consistency of the provided information. The service network also includes a central Data Centre and the SSA Space Weather Coordination Centre (SSCC). In this presentation we give an overview of the current status of the network (http://swe.ssa.esa.int/), the targeted end-user groups and Expert Service Centres with a focus on the space community.

The detection of ultra-relativistic electrons in low Earth orbit

Aims. To better understand the radiation environment in low Earth orbit (LEO), the analysis of in-situ observations of a variety of particles, at different atmospheric heights, and in a wide range of energies, is needed. Methods. We present an analysis of energetic particles, indirectly detected by the large yield radiometer (LYRA) instrument on board ESAs project for on-board autonomy 2 (PROBA2) satellite as background signal. Combining energetic particle telescope (EPT) observations with LYRA data for an overlapping period of time, we identified these particles as electrons with an energy range of 2 to 8 MeV. Results. The observed events are strongly correlated to geo-magnetic activity and appear even during modest disturbances. They are also well confined geographically within the L  = 4–6 McIlwain zone, which makes it possible to identify their source. Conclusions. Although highly energetic particles are commonly perturbing data acquisition of space instruments, we show in this work that ultra-relativistic electrons with energies in the range of 2–8 MeV are detected only at high latitudes, while not present in the South Atlantic Anomaly region.