D. Heynderickx, B. Quaghebeur, J. Wera BIRA, Ringlaan 3, B-1180 Brussel, Belgium

1. ESA'S SPACE ENVIRONMENT INFORMATION SYSTEM (SPENVIS): A WEB-BASED TOOL FOR ASSESSING ENVIRONMENTAL EFFECTS IN SPACECRAFT SYSTEMS D. Heynderickx, B. Quaghebeur, J. Wera BIRA, Ringlaan 3, B-1180 Brussel, Belgium

2. Overview • Overview of space environment and effects • Description of SPENVIS • Architecture • Models and tools • Ongoing and future extensions and upgrades • Commercial break • Demonstration

4. What is SPENVIS? • WWW based interface to models of the space environment and its effects on spacecraft and components: • radiation environment • dose, NIEL, SEUs, solar cell degradation • spacecraft charging • magnetic fields • atmosphere and ionosphere • meteoroids and debris • solar irradiance, … • Models are run over spacecraft trajectories or coordinate grids • Access to satellite data sets and geomagnetic indices • On-line help and extensive background information • Results in textual, tabular and graphical form

5. User Community • Intended usage: • spacecraft engineering • scientific • educational support • Currently about 2,000 internationally registered users • Listed on NASA’s Technical Standard site • Used by major spacecraft industries and universities

6. SPENVIS Architecture • HTML interface which stores input parameters in text files • CGI script spawns runs of stand-alone binaries • Output from applications has been converted to straightforward ASCII files with standard headers • Output files can easily be downloaded and ingested in other applications (e.g. Excell provides direct import of tables in HTML files) • Graphics are produced with IDL; this can be replaced by other packages if needed. • Ongoing development to move from CGI scripts to php, similar to LAMP/WAMP (Linux/Windows-Apache-MySql-php). • Very flexible architecture, easy to maintain and expand. • Framework for other applications

7. Radiation environment • Spacecraft orbit generator • Runge-Kutta trajectory tracing • Parameter input: 6 orbit parameters, pre-defined orbit types (heliosynchronous, GEO), Two Line Elements • Trajectory file uploads • Environment models • trapped protons (including anisotropy) and electrons • solar ions • cosmic ray ions (GCR, ACR) • Geomagnetic shielding for SEPs and CRs

8. Radiation effect models ionizing dose non-ionizing dose solar cell degradation: damage equivalent electron fluence for different cell type single event upsets Mulassis: Geant4 Monte Carlo code for shielding analysis Radiation effects

9. Radiation effects • Sector analysis tool • Basic building blocks (sphere, box, cylinder) to construct 3D model of satellite system • VRML view of geometry • 1D and 3D shielding distributions can be folded with flux and dose models

10. Magnetic Field • Orbital and grid version • Field models: • internal: IGRF/DGRF • external: Mead-Fairfield, Olson-Pfitzer quiet and dynamic, Tsyganenko 87/89/96/01/04, Ostapenko-Maltsev, Alexeev (ISO draft standard) • Drift shell tracing • Used for trapped particle models (automatic selection of appropriate models) and geomagnetic cut-off calculations • Fortran library: http://www.oma.be/NEEDLE/unilib.php/

11. Atmosphere and Ionosphere • Models: NRLMSISE-00, MET V2, DTM, IRI-90, HWM • Evaluation over spacecraft orbit: • density, flux, and fluence of atmospheric or ionospheric constituents on an oriented surface along an orbit • erosion depths for atomic oxygen • Over coordinate grids

12. Spacecraft Charging • Data sets: GORIZONT/ADIPE, CRRES/LEPA • LEOPOLD: Environment parameters as a function of altitude • DICTAT: internal deep dielectric charging • FLUMIC trapped electron model • Cylindrical and planar configurations • Estimate of electrical breakdown and suggestions for design improvement • SOLARC: interaction of solar array and spacecraft with plasma environment • EQUIPOT: analysis of spacecraft surface charging • Simple isolated patch on conducting sphere model • Includes major current systems • Extended with Katz secondary electron model

13. Meteoroids and Debris • Flux as a function of mass or diameter • Grün meteoroid model • Debris models: • NASA-90 • NASA-96 • Impact risk analysis • Critical impacting particle diameter derived from particle/wall interaction model • Probability of puncture • Velocity distributions

14. Other Models and Tools • Interface to data bases: • satellite data: GOES-5-6-7-8-9-10/SEM, ISEE-1/WIM, ISEE-2/KED, Meteosat-3/SEM-2, STRV-1B/REM, CRRES/MEA, SAMPEX/PET, UARS/PEM, AZUR/EI-88, MIR/REM • magnetic and solar indices and parameters • format: CDF (ISTP/IACG guidelines) with IDL interface and plotting library • Links to and from ECSS-E-10-04 standard • Visualization of coordinate transformations • Solar irradiance • Geomagnetic cut-off maps

15. Ongoing and future extensions to SPENVIS • Upgrade of the orbit generator: new trajectory types (hyperbolic, parabolic, interplanetary, manoeuvres) • Implementation of new environment models (SEP, CR, …) • Implementation of new methods for solar cell degradation studies: direct NIEL, SAVANT • Upgrade of NIEL calculations (electron and neutron NIEL, extensions to Mulassis) • Extension of SEU module to new devices • Upgrade of the sector analysis tool: more shapes, stand-alone geometry interface, interface to Geant4 geometry definition • Interface to Geant4 GRAS code: advanced toolkit for shielding simulations • Interface with external codes and tools (SIREST)

16. New interface in PHP • The SPENVIS 5.0 interface will be completely written in PHP. • Object oriented • Well documented • Easy to maintain or modify • Easy to extend • Easy to use without knowing all the implementation details

17. For the users • Updated layout • Better navigation possibilities including an expandable navigation menu on the left • Easier to work with

18. For the developers • More flexible environment • Object-oriented script with PHP classes that allow running models and making plots • Layout template that includes the expandable navigation menu on the left

19. Currently implemented interfaces • Spacecraft trajectories (SAPRE) • Coordinate grid generator (GRID) • Trapped Radiation Models • Proton Models • AP-8 (developed by NSSDC) • CRRESPRO (developed by Air Force Research Lab) • SAMPEX/PET PSB97 (developed by BIRA) • Electron Models • AE-8 (developed by NSSDC) • CRRESELE (developed by Air Force Research Lab) • AE-8 MIN Update ESA-SEE1 (developed by A.L. Vampola)

20. Commercial break • SPENVIS is available at http://www.spenvis.oma.be/ • Use of the Web service is free, but needs registration • Concept of ‘advanced’ users has been introduced: additional control on input parameters and model runs for selected users; this is one option for future commercialisation • Commercial licences for PC Windows and Linux can be purchased • One more GSTP contract extension has been approved, but this will be the final one; afterwards, SPENVIS will have to be self-supporting. • SPENVIS is linked with ECSS E-10-04 standard on space environment, and will be linked with new standards on radiation effects and spacecraft charging