ESA'S SPACE ENVIRONMENT INFORMATION SYSTEM (SPENVIS): A WEB-BASED TOOL FOR ASSESSING ENVIRONMENTAL EFFECTS IN SPACECRAFT SYSTEMS

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

Overview

• Overview of space environment and effects• Description of SPENVIS

• Architecture• Models and tools• Ongoing and future extensions and upgrades

• Commercial break• Demonstration

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

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

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

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

Radiation effects

• 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

• 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

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/

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

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

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

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

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)

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

For the users

• Updated layout• Better navigation possibilities including an expandable

navigation menu on the left• Easier to work with

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

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)

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