Description
Priority 2 activities will only be initiated on the explicit request of at least one delegation.
Objective:
The objectives of the activity are to develop an operational tool to reduce errors in shielding analyses andassociated data exchanges, and quantify design margins more accurately.
Targeted Improvements:
Improving the accuracy of radiation shielding analysis will release a source of hidden design margins; if more accurate tools are available, computed radiation levels will be lower, allowing a relaxation of procurement radiation hardness requirements, reducing costs. An accurate transfer of radiation shielding and dose environment information between spacecraft and unit manufacturers will have similar benefits.
Description:
Recent years have seen significant improvements in the accuracy of radiation tools for the analysis of radiation effects at spacecraft, equipment, and parts level. Despite past efforts, deficiencies still persist in the link between system configuration and the designof radiation countermeasures, significantly limiting the accuracy and the efficiency of the industrial process. Traditional radiation shielding analyses performed during the radiation hardness assurance (RHA) process are assumed to be conservative. However, these methods assume radiation travels in straight lines, ignoring the physics of interactions of the main hazard to telecommunications missions - electrons - that scatter greatly and create secondary radiation in random directions. While it is appreciated that errors are probable, this is thought to be compensated by underestimation of spacecraft mass distribution, and the application of techniques such as assuming perpendicular propagation through walls.
In addition, methods to specify spacecraft effective shielding and dosesat unit level ("6-faces") are similarly questionable, as highlighted by an ESA TRP activity. These factors particularly affect the commercial space sector, where confidentiality of the geometry models excludes detailed the transfer of design information. Also, the fast turn-around of analyses in telecom programmes has made the use of detailed but slower analysis tools (based on Monte Carlo transport techniques) impractical (at least until very recently), therefore limiting the benefit that could come from the recent improvements in accuracy for in-flight prediction of both Ionising and Non-Ionising dose.
This activity will build upon the exploratory TRP work to develop a fully operational industrial toolkit with shielding analysis and data exchange capabilities.
The proposed work logic is the following:
- Analyses of techniques for Ionising and Non-Ionising Dose calculation and information exchange (ray-tracing, 6-faces, 3-D Monte Carlo), in order to verify accuracy and quantify the conservatism in current industrial procedures. (This is essential for establishing margins in the RHA process).
- Development of a new shielding information exchange method based on/combined with Monte Carlo calculation at spacecraft level, including support for the HDF5 format. ï· Detailed analysis of the accuracy of current industrial sectorial analysis of radiation effects with respect to detailed 3-D Monte Carlo techniques. This is to address therisk from potential under-prediction, and has implication for ECSS standards (E-ST-10-12).