GIOVE-A 3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey GIOVE-A Radiation Environment Study Regime and Instrument Description B Taylor, C Underwood (University of Surrey) S Jason, S Fellows, E Rooney (SSTL) K Ryden, D Rodgers, P Morris (QinetiQ) G Gatti, G Mandorlo, H Evans, E Daly (ESA)

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey2 Outline The MEO Radiation Environment Galileo & the GIOVE-A Spacecraft GIOVE MEO Environment Goals Radiation Monitors onboard GIOVE Timeline

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey3 The MEO Radiation Environment Cosmic Rays –Constant background flux of protons and heavy ions –Well defined energy spectrum up to ~10 20 eV Solar Proton Events –Predominantly encountered at solar maximum, few at solar minimum –Geomagnetic field provides varying protection

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey4 The MEO Radiation Environment Outer radiation belt –Significant proton fluxes confined below ~4 RE –Outer Belt composed of Electrons –Extends between 3 - 7RE –>1 MeV flux peaks at around ~4-5 RE at ~ electrons cm -2 s -1 GIOVE-A Orbit

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey5 The MEO Radiation Environment Environment Models –AE-8 Standard for engineering use Mostly empirical, little physics Based on data from satellites from 60’s & 70’s Static, long term average model Covers entire range of belt Versions for Solar Max & Solar Min –CRRESELE Based on 2 years of data from GTO at Solar max

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey6 The MEO Radiation Environment Environment Variability –Distribution varies greatly due to solar cycle –Spatial distribution varies due to geomagnetic field variation at higher altitudes –Injection events due to geomagnetic storms can enhance environment by orders of magnitude –Closely linked to Solar activity

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey7 The MEO Radiation Environment Environment dangers and effects –Total Ionising Dose (TID) caused by energetic particles (electrons, protons and heavy ions) –Single Event Effects (SEE) caused by energetic heavy ions and protons –Electrostatic Discharge (ESD) – caused by penetrating electrons

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey8 The MEO Radiation Environment Previous MEO Spacecraft –Combined Release and Radiation Effects Satellite (CRRES) Launched into Geostationary Transfer Orbit (GTO) in 1990 ~1 year mission –Space Technology Research Vehicles (STRV) Two satellites launched into GTO in 1994 ~2.5 year mission –GPS Multiple spacecraft carry radiation detectors Data is property of US DoE - limited access

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey9 The MEO Radiation Environment Solar Cycle Coverage –GIOVE-A lifetime is over solar minimum –GIOVE combined with STRV gives data on two consecutive solar minima –CRRES data at solar maximum

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey10 Galileo Galileo- The European Global Navigation Satellite System (GNSS) –Independent, commercial system –Two test bed spacecraft – GIOVE -A & -B –Four In Orbit Validation (IOV) spacecraft –Final constellation to consist of 30 satellites, 27 active, 3 spare in 3 orbital planes –Total cost of system: ~€3-4 billion

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey11 GIOVE-A Spacecraft GIOVE-A –Precursor to Galileo Programme –Objectives Secure frequency filing Demonstrate key payload technologies Provide Signal-in-Space for Experimentation Measure MEO environment –Requirements Two year mission lifetime Low cost, rapid schedule Kick-Off - July 2003 and Launch – 29 th December 2005

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey12 MEO Environment Goals Optimise the design of the Galileo satellites –Confirm requirements are correct, modify if necessary Are existing models a good enough description of the environment? –LET spectrum –Electron Fluxes –Total Ionising Dose –Dose rates

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey13 Radiation Monitors on GIOVE-A MERLIN – QinetiQ –Cosmic-Ray LET Spectra –Proton Flux –Total Ionising Dose –Electrons/ Deep Charging Currents CEDEX – UniS/SSTL –Cosmic-Ray LET Spectra –Proton Flux –Dose-Rate Induced Photocurrents

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey14 Radiation Monitors on GIOVE-A CEDEX Merlin

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey15 Radiation Monitors on GIOVE-A Radiation Monitors

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey16 Radiation Monitors onboard GIOVE-B SREM- ESA –Due for Launch late 2007 on GIOVE-B –Three precision particle detectors Electrons & Protons –Internal total dose measurement

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey17 Timeline – Initial Operations CEDEX & Merlin turned on - 29 th December 2005 –Second contact after launch –Operated near continuously since first switch-on Environmental Readiness Review (ERR) 06/04/2006 Environmental Payloads Commissioning Phase –Setup of download and processing chain Initial Operations Phase –Initial analysis of data with simplified shielding models

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey18 Timeline – Main Operations Main Operations Phase – Part 1 –Simplified 1D Mulassis, and 3D GEANT-4 model of the payloads/ spacecraft. –Results compared to AE8/CRRESELE Main Operations Phase – Part 2 –Electron response of Merlin using Geant4, SREM data expected (but now delayed) –Data compared with static and quasi-static models (AE8, FLUMIC, CRRESELE, ESAMEA, etc). –Results used to validate modelling performed in MOP-1 –Pile-up induced responses to electrons in Proton Flux measurements from Merlin investigated to derive further data on electron environment

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey19 Conclusions Merlin and CEDEX have been operating since December 2005 Initial commissioning activities are complete Data analyses continue to be refined The following two papers will describe the units in more detail and present the in-orbit results

3 rd Euro Space Weather Meeting, Nov 2006 ©SSTL/University of Surrey20 Thank you for your attention For further information contact : Dr Elizabeth Rooney Surrey Satellite Technology Limited Tycho House, 20 Stephenson Road, Surrey Research Park, Guildford, Surrey, GU2 7YE, UK Tel: , FAX: Web: