Session 10 - Spacecraft operations and space weather

Dave Pitchford (SES), Richard Horne (BAS)
Thursday 17/11, 10:00-13:00
Ridderzaal

Spacecraft survivability – robustness to the Space Environment and its dynamism – Space Weather, is an important part of business for those planning, building and operating spacecraft.
This session is the latest in a series aiming to bring together the research, engineering and operations communities.
Topics to be covered include:
-Analysis of Space Weather events – declining phase electron enhancements and spacecraft charging.
-Evolving space missions – MEO and LEO constellations such as O3B & OneWeb, Electric Orbit Raising Missions driving evolving needs for data, models and forecasts.
-Hosted sensors for Space Weather – filling the gaps in forecasts and models.

Poster Viewing
Thursday November 17, 10:00 - 11:00, Poster Area

Talks
Thursday November 17, 11:00 - 13:00, Ridderzaal

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Talks : Time schedule

Thursday November 17, 11:00 - 13:00, Ridderzaal

11:00	Low energy electrons at MEO during observed surface charging events	Ganushkina, N et al.	Oral
	Natalia Ganushkina[1,2], Ilkka Sillanpää[1], Jean-Charles Matéo-Vélez[3], Stepan Dubyagin[1], Angélica Sicard Piet[3]
	[1]Finnish Meteorological Institute, Helsinki, Finland; [2]University of Michigan, Ann Arbor MI, USA; [3]ONERA The French Aerospace Lab, Toulouse, France
	The physics-based, research-oriented Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM) traces ions and electrons with arbitrary pitch angles from the plasma sheet to the inner L-shell regions with energies reaching up to hundreds of keVs in time-dependent magnetic and electric fields. The tracing of a distribution of particles is conducted in the drift approximation under the conservation of the first and second adiabatic invariants. Liouville's theorem is used to gain information of the entire distribution function. Low energy electrons (< 100 keV) which are successfully modeled by IMPTAM are responsible for surface charging events. GEO is populated with satellites and several of them are doing continuous and available in real time measurements and surface charging events were clearly identified there. At the same time, not much information on particle fluxes is available at MEO. There is no easy way to say what will be the flux of < 100 keV electrons at MEO when surface charging events are detected at GEO than to use a model. IMPTAM electron fluxes are now available at MEO orbit. As a first step, we set a MEO orbit similar to Galileo orbit with 56° inclination, the period of 14 hours, at distance 23 222 km (4.6 Re from the center of the Earth). Several surface charging events at GEO were identified using LANL MPA (Magnetospheric Plasma Analyzer), SOPA (Synchronous Orbit Particle Analyzer) and EPD (Energetic Particle Detector) electron data for energies from 1 eV to several MeVs. The IMPTAM output was made as the electron fluxes with energies of 1 to 100 keV at MEO for all events. It was found that the electron fluxes modeled by IMPTAM at the locations of the observed fluxes at GEO (LANL location) reached their maxima at MEO in about 2 hours and were situated at around 06 MLT with values of 1 order of magnitude higher than at GEO. In order to validate the IMPTAM output at MEO, we conduct the statistical analysis of measured electron fluxes onboard Van Allen Probes (ECT HOPE (20 eV-45 keV) and ECT MagEIS (30 - 300 keV) at distances of 4.6 Re. These results help to assess the risk to satellites in MEO from surface charging due to low energy electrons, how the risk changes for satellite launched at different times during the solar cycle on the basis of the space environment specified by IMPTAM. The research leading to these results was partly funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No 606716 SPACESTORM and by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 637302 PROGRESS.
11:20	Validating long-term simulations with the BAS Radiation Belt Model using GIOVE-B data	Glauert, S et al.	Oral
	Sarah A Glauert, Richard B. Horne, Nigel P. Meredith
	British Antarctic Survey, Cambridge, UK
	It is becoming increasingly important to understand the electron radiation environment at medium earth orbit (MEO). Global navigation satellites operate in this region of space and satellites that use electric orbit raising to reach geostationary orbit (GEO) can also spend hundreds of days here. Unfortunately, there is limited data on the high-energy electron flux, responsible for internal charging, in this region. One approach to this problem is to use models to recreate the environment. As part of the EU-FP7 SPACESTORM project, the BAS Radiation Belt Model (BAS-RBM) has been used to recreate the high-energy electron environment (E > ~500 keV) throughout the outer radiation belt, between the outer edge of the inner belt and geostationary orbit, for the last 30 years. The >2 MeV electron flux has been measured at GEO by the GOES spacecraft for more than 30 years, providing a data set from which the outer radial boundary condition for the BAS-RBM can be derived. The resulting, 30 year long simulation illustrates both the long and short term variability of the outer radiation belt and slot region; solar cycle variations are clearly visible. For a period in 2008-2012, the Standard Radiation Environment Monitor (SREM) on the Galileo In-Orbit Validation Element-B (GIOVE-B) spacecraft provided count rates for the high-energy electrons in MEO. These can be used to provide a completely independent validation of the BAS-RBM during this period, once the fluxes predicted by the simulation are converted to count rates, using the SREM response functions. We will present a comparison between the simulation and the GIOVE-B data, including the calculation of skill scores, for the whole GIOVE-B data set.
11:40	Extreme Internal Charging Currents in Medium Earth Orbit: Analysis of SURF Plate Currents on Giove-A	Meredith, N et al.	Oral
	Nigel Meredith[1], Richard Horne[1], John Isles[1], Keith Ryden[2], Alex Hands[2], Daniel Heynderickx[3]
	[1]British Antarctic Survey; [2]Surrey Space Centre; [3]DHC Consultancy
	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 an extreme space weather event. In this study we conduct 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 1 in 10 year top plate current decreases with increasing L* ranging from 1.0 pAcm^-2 at L* = 4.75 to 0.03 pAcm^-2 at L* = 7.0. The 1 in 100 year top plate currents are a factor of 1.2 to 1.8 larger than the corresponding 1 in 10 year event. The 1 in 10 year middle and bottom plate currents also decrease with increasing L* ranging from 0.4 pAcm^-2 at L* = 4.75 to 0.01 pAcm^-2 at L* = 7.0. The 1 in 100 year middle and bottom plate currents are a factor of 1.2 to 2.7 larger than the corresponding 1 in 10 year event. 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 pAcm^-2.
12:00	Energetic electron dynamics in the inner magnetosphere during the 2015 "St Patrick's Day" storm	Morley, S et al.	Oral
	Steven Morley, John Sullivan, Thiago Brito, Michael Henderson, Jesse Woodroffe, Vania Jordanova
	Los Alamos National Laboratory
	The St. Patrick's Day storm of March 2015 was notably the largest storm of solar cycle 24 so far. We combine data from several satellite missions, forming a virtual constellation of more than 20 satellites, and use these data to describe the dynamics of the storm in detail. The virtual constellation includes: Van Allen Probes; Los Alamos National Laboratory (LANL) geosynchronous satellites; and the Global Positioning System fleet. We explore the electron dynamics from the keV energies relevant for surface charging through to MeV energies. We also place this storm in the context of other large storms in solar cycles 22, 23 and 24.
12:20	What Effect Do Substorms Have On The Content Of The Radiation Belts?	Forsyth, C et al.	Oral
	Colin Forsyth[1], Jonathan Rae[1], Kyle Murphy[2], Mervyn Freeman[3], Chia-Lin Huang[4], Harlan Spence[4], Alexander Boyd[4], John Coxon[5], Caitriona Jackman[5], Nadine Kalmoni[1], Clare Watt[6]
	[1]UCL Mullard Space Science Laboratory, Dorking, UK; [2]NASA Goddard Space Flight Centre, Maryland, USA; [3]British Antarctic Survey, Cambridge, UK; [4]University of New Hampshire, Durham, USA; [5]University of Southampton, Southampton, UK; [6]University of Reading, Reading, UK
	Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV "seed" population into the inner magnetosphere which is subsequently energized through wave particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following substorms and quiet intervals. However, there are up to three times as many increases in TRBEC following substorm intervals. There is a lag of 1-3 days between the substorm or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following substorms and quiet intervals, the mean change in TRBEC following substorms or quiet intervals and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYMH, but decreases in the radiation belt show no apparent link with magnetospheric activity levels.
12:40	Space Weather Situational Awareness Training and Operational Readiness	Haggarty, E et al.	Oral
	Ewan Haggarty
	Airbus Defence and Space
	This talk is an update on the progress made at Airbus Defence and Space to generate a training package and exercise package for satellite operations staff covering extreme Space Weather scenarios. Also discussed is an Operational Concept including procedures, event thresholds and action plans to cover Extreme Space Weather scenarios.

Posters

Thursday November 17, 10:00 - 11:00, Poster Area

1	Long-term and Short-term Variation of Absorbed Dose Values on the Medium Earth Orbit.	Protopopov, G et al.	p-Poster
	Vasily S. Anashin[1], Grigory A. Protopopov[1], Olga S. Kozyukova[1], Igor A. Lyakhov[1], Sergey G. Rukavichnikov[1], Pavel V. Shatov[2]
	[1]Branch of JSC URSC-ISDE; [2]FSBI Fedorov Institute of Applied Geophysics
	The analysis of flight data is presented in the paper. The flight data are dose sensor measurements on the navigation orbit. The dose sensors operate on metal-nitride-oxide-semiconductor dosimetry pricniple. The data have been accumulating for more than 7 year. Long-term (annual) and short-term (per day) variation of dose sensor measurements are shown and discussed. We observed abrupt dose rate increasing events and variation of annual dose values. These events and variation are analyzed with taking into account of charge particles fluxes (from GOES system and Electro-L spacecraft) and other space weather characteristics such as geomagnetic activity, period of solar cycle and others. The analysis results, statistics of increasing events and its correlation with other space weather characteristics will be presented in the full paper.
2	The behavior of high-energy magnetospheric electrons during solar cycles 22 and 23	Kryakunova, O et al.	p-Poster
	Anatoly Belov[1], Olga Kryakunova[2], Artem Abunin[1], Maria Abunina[1], Sergei Gaidash[1], Irina Tsepakina[2]
	[1]Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation (IZMIRAN), Moscow, Russia; [2]Institute of Ionosphere, Almaty, Kazakhstan
	The daily fluence of electrons was selected as the main characteristic of the behavior of electrons with energy> 2 MeV measured by GOES satellites at geostationary orbit, since it is closely related to malfunctions of satellite electronics. It is shown that the increases of high-energy magnetospheric electrons begin during major interplanetary and magnetospheric disturbances, but the beginning of the electron increases lags behind them for 1-3 days. Significantly increased solar wind speed is observed for 3 days before to the beginning of the electron increase, reaching a maximum by the beginning of the increase. It is shown that the electron fluence was weakly linked to the level of geomagnetic activity on the same day, but was correlated with Ap-index of geomagnetic activity observed 2-3 days before. Fluence of high-energy magnetospheric electrons is closely connected with the solar wind speed, especially measured 2 days earlier.
3	Risk index of spacecraft surfacing charging effects in auroral region	Meng, X et al.	p-Poster
	Xuejie Meng, Dong Chen, Liqin Shi
	National Space Science Center, Chinese Academy of Sciences
	High level spacecraft surface charging, which is frequently observed in aurora region, may lead to electrostatic discharges and consequently significant damage of the satellite. In this letter, the surface charging events of DMSP in the aurora region are identified and listed based on precipitating ion/electron energy spectra and plasma density. The relationship between the charging events and the geomagnetic activity indices are investigated statistically. Since the geomagnetic indices can be forecasted through the existing models which utilize the upstream solar wind parameters as input, we propose a geomagnetic index-based surface charging risk index. This index could predict the likelihood of surface charging events in auroral region. Therefore it could serve as a tool for spacecraft risk analysis.
4	Radiation Effects on Satellites during Extreme Space Weather Events	Hands, A et al.	p-Poster
	Alex Hands[1], Keith Ryden[1], Nigel Meredith[2], Sarah Glauert[2], Richard Horne[2]
	[1]University of Surrey; [2]British Antarctic Survey
	The threat to satellites from high energy radiation in the space environment is well known. One of the most significant hazards comes from the charging of dielectric materials or isolated conductors under relatively low levels of shielding in the spacecraft structure. The build-up of charge can lead to unsustainably high electric fields that lead to electrostatic discharges (ESDs) and the subsequent failure of components or systems. The high energy electron population that causes internal charging, also leads to total ionising dose (TID) and displacement damage dose (DDD) in components and materials. 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 a greatly enhanced risk of satellite failure. The EU FP7 Spacestorm project has used statistical analysis of electron flux and charging current data sets to characterise worst case events over long time periods in geostationary and medium Earth orbits. In addition, a radiation belt model has been used to produce a reconstructed 30 year data set of the trapped electron environment, from which further deductions of extreme environments can be made. We use the extreme environments generated by Spacestorm to estimate the consequences for satellites in terms of the radiation effects described above. A worst case event could lead to significant losses in terms of capability degradation and complete satellite failure. In consequences for such losses are hugely significant given our increasing reliance on satellites for a vast array of services, including communication, navigation, defence and critical infrastructure. Therefore we also examine the implications for satellite design and radiation effects mitigation.