Internal Charging Tool - DICTAT

ESA's Technology Research Programme; Ref. Contract 12115/96/NL/JG(SC); with DERA (GB) and ONERA/DESP (F); 1997-1999


Electrostatic discharges (ESDs) caused by the disposition of charged particles (mainly radiation belt electrons) within dielectrics have been shown to be a major cause of satellite anomalies. In the past, calculations of this internal charging have relied on computer-intensive Monte-Carlo simulations. However satellite design engineers generally do not need the detail that such an approach provides and instead require a fast, easy-to-use design aid. The purpose of this contract is to develop such a practical engineering tool to help assess whether structures near the surface of a spacecraft are liable to experience electrostatic discharges as a result of internal charging. The tool is based on basic physics and empirical equations and can be applied to planar and cylindrically symmetric structures. Both in-orbit and laboratory test situations can be simulated.

An additional important goal of the tool is that it should provide the user with a possible corrective action, which may be taken to avoid the problem (i.e. minimum shielding, minimum conductivity or other).

See also the presentation from the Final Presentation Days in 1999, which were organised to report on the technology research in the space environments and effects area.

Products and Information

For more detailed information see the DERA web site dedicated to the work.

A Final Report for the first phase of the work is also available. It proposes an engineering specification in terms of a set of models that represent the most up-to-date knowledge of internal dielectric charging, reports on the development of a simple to use software DICTAT supporting the specification and describes the efforts experimentally to validate the tool.

Although the development and validation of the tool is still ongoing, the first version has been released and can be accessed via SPENVIS.

A Final Report for the second phase of the work is now available.


The development was initiated following the presentation of the paper An Engineering Specification of Internal Charging at the ESA symposium on Environment Modelling for Space-based Applications in Noordwijk 18-20 September 1996.

The initial results of the work has been presented at the workshop on Space Radiation Environment Modelling in Moscow 7-9 October 1997 in a paper titled: An Engineering Tool for the Prediction of Internal Dielectric Charging. More recently it was presented at the Spacecraft Charging Conference in Boston 2-6 November 1998 in a paper titled  An Engineering Tool for the Prediction of Internal Dielectric Charging by D.J. Rodgers, K.A. Ryden, G.L. Wrenn, P.M. Latham, J. Sørensen, L. Levy.



Paul Latham

D. Rodgers

Keith Ryden

Gordon Wrenn


Leon Levy


J. Sørensen