ECSS Space Environment Standard

The European Co-operation for Space Standardization (ECSS) is producing a system of standards covering all aspects of space mission execution. Within the System Engineering branch ("E") is:

  • a Space Environment Standard, ECSS-E-ST-10-04C;
  • a standard for calculation of radiation effects and a policy for design margins, ECSS-E-ST-10-12C;
  • and a standard on spacecraft chargin, ECSS-E-ST-20-06C.

As "level 3" engineering standards, they aim to provide authoritative information which will help make design, development and execution of missions more efficient. In this engineering process, it is important that environments and their effects are properly understood and taken account of and suitable margins specified to mitigate against uncertainties. In addition, use of a common standard ensures visibility of practices between collaborating companies or organisations.

 

Click the following for more information on each standard.

 

ECSS-E-ST-10-04C ...

The standard provides information on the various aspects of the space environment and their effects. Where possible it identifies recognised standard models of the environment and methods for assessing the effects. The environments covered are: gravitation; geomagnetic field; solar and earth electromagnetic radiation and indices; atmospheres; plasmas; energetic particle radiation; particulates; and contamination.

 

In some of these areas, well-established internationally recognised standard models exist, such as the International Reference Ionosphere, the International Geomagnetic Reference Field and the COSPAR International Reference Atmosphere. In others, widely used models and methods have become de-facto standards. Problems were identified with lack of internationally accepted standards or with models which had shortcomings. As a result, it is expected that the Standard will continually evolve as these problems are resolved. Co-ordination with CEN, COSPAR, ISO and other organisations is underway. An "active" www-based version is under development within SPENVIS (the Space Environment Information System).

 

ECSS-E-ST-10-12C ...

This standard covers the methods for the calculation of radiation received and its effects, and a policy for design margins. Both natural and man-made sources of radiation (e.g. radioisotope thermoelectric generators, or RTGs) are considered in the standard.

The standard includes methods for calculating the effects of radiation shielding on the amount, type and energy of radiation arriving at a component location; these methods range from the simplified geometric methods to the more complex Monte-Carlo methods. The radiation effects calculation methods include total ionising dose (TID), Non-Ionising Dose (NID) and displacement damage,  Single Event Effects (SEE), radiation induced sensor background and the effects in biological materials.

ECSS-E-ST-20-06C ...

This standard addresses the electrical interaction between a spacecraft and the space environment. This interaction can arise from a number of external sources including the ambient plasma, radiation, electrical and magnetic fields and sunlight. The nature of these interactions and the environment itself can be modified by emissions from the spacecraft itself, e.g. electric propulsion, plasma contactors, secondary emission and photoemission.

The standard aims to ensure the appropriate assessment and mitigation of effects in a wide range of plasma environments including geostationary, medium and low Earth orbits. Effects addressed include surface plasma interactions leading to spacecraft charging, secondary arcing on solar arrays, high voltage current collection from  the ambient plasma, internal dielectric charging within spacecraft materials caused by high energy electrons, electrostatic tether interactions and electric propulsion.

The requirements are based on the best current understanding of the processes involved and building on existing de-facto standards in many cases. As well as providing requirements, the standard provides a brief explanation of the main effects so that interested parties at all stages of the design chain can have a common understanding of the problems faced and the meaning of the terms used.

Annexes follow the main text and include discussion of types of orbits and how to tailor the requirements according to the mission, quantitative assessment of the physical processes behind the main effects, computer simulations and testing and measurement.



The official site for accessing the ECSS documents is www.ecss.nl. This site should be consulted to obtain the latest official version of the standards. The previous ECSS-E-10-04a standard is also available in HTML format via the Space Environment Information System (SPENVIS), complete with links directly from the standard to the respective models accessible in SPENVIS. The versions linked below are to draft versions of the document.