ESA Open Source Policy

Open Source Software (OSS) is computer software recognised by the Open Source Initiative (OSI), whose source code is made available under a copyright licence that allows users to use, study, change, and improve the software, and to redistribute it in a modified or unmodified form.

The use of OSS world-wide has increased significantly in the last decade to the point that OSS plays today an essential role in all industrial sectors and government, including space and defence.

This trend is due to the generally perceived benefits of OSS, namely:

• increases software quality;
• reduces development and maintenance costs for the individual users;
• avoids vendor lock-in;
• facilitates rapid evolution of the software;
• encourages reuse of software;
• fosters industrial competitiveness;
• develops lucrative consulting, training and support services offering.

ESA could not remain oblivious to this trend: in the last two decades, ESA, like any other relevant organisation using and procuring software, has increasingly been making use of OSS. Since 2004, the General Clauses and Conditions for ESA contracts, ESA/REG/002, rev. 2 (“GCC”)[1] (sub-clauses 42.10 and 42.11) foresee the possibility of open source licensing of software developed under ESA contracts.

In addition, not least due to industrial commercial interests, ESA had to implement an effective OSS strategy that opens the necessary opportunities for industry in a global market, inside and outside of the space sector. A clear strategy on OSS consolidates the leadership of ESA in software developments for the space sector and allows ESA to fulfill its mandate as a focal point for European research and innovation.

Considering the risks and potential consequences associated with the distribution of the OSS for ESA, it is of the utmost importance that the ESA Software Licensing Board authorisation is granted and recorded in a Software Licensing Authorisation (SWLA) prior to any distribution of any software outside ESA.

Distribution of Open Source Software within the ESA Member States[2]

When there is no need/added value to implement a world-wide OSS scheme, an “ESA Community Software” licensing regime can be implemented. In this case use, modification and further licensing of the software shall be restricted to individuals or entities belonging to the ESA Member States.

This software is defined as software licensed according to the main principles of Open Source, with the major exception of the Licensed Territory being limited to the ESA Member States. This limitation makes this type of licensing incompatible with the commonly accepted definition of Open Source given by the Open Source Initiative[3], which requires unrestricted distribution.

Such software would therefore benefit from the OSS philosophy while remaining within the ESA environment and should be made available as part of the European Space Software Repository[4].

Distribution of Open Source Software outside the ESA Member States

This scheme is generally suitable for the application cases described as software supporting the implementation of open standards or the processing of mission data.

For developments initiated by ESA, not subject to pre-existing licensing constraints, ESA’s own OSS licence template shall be revised, ensuring compatibility with the ESA internal procedures and licensing standards. In particular, the Industrial Policy Committee (IPC) approval is required prior to any distribution of an ESA owned software outside of the ESA Member States.

In case pre-existing, non-ESA, OSS is adopted as a basis for ESA procurements, the licensing regime for the derived work would by definition be the one applicable to the existing product itself. Since certain OSS licences are not compatible with the ESA rules or may inflict unwanted constraints, any proposal for re-using existing OSS shall be checked against a list of acceptable OSS licences.

For the cases entailing world-wide distribution (“proper” OSS), the main possible cases are the following ones:

1. MODIFICATIONS TO EXISTING OSS

(licensing framework is inherited),

• An OSS product exists that can fulfil ESA project needs after a proper qualification is carried out, which may imply modifications to the product to correct deficiencies or pass the qualification (e.g. the RTEMS).

1. SOFTWARE DEVELOPMENT RELYING UPON EXISTING OSS

(licensing framework is inherited)

• ESA contributes to an international collaboration, typically universities and research centres, like GEANT4, or develops software that relies on existing OSS that imposes the use of a non-ESA licence;
• Diffused ownership of existing Intellectual Property (IP): individual contributors (as ESA could be) only “own” the parts they have added or modified and these are, in most cases, meaningless if separated from the overall software product. No single owner or licensor can be identified to, e.g. obtain a different or non-OSS type of licence on the product to accommodate the requirements stemming from the ESA’s current legal frame;
• ESA’s contribution is a (generally small) part of a much larger and independently pre-existing reality. ESA can greatly benefit (cost reduction, development risk mitigation, large validation base, etc.) from the existing IP but is not in a position to influence the existing licensing arrangements within the users/developers community;
• Impossible to control export aspects beyond ESA.

1. NEW OSS DEVELOPMENT

(licensing framework imposed by ESA)

• ESA initiates a development that falls under one of the scenarios considered appropriate for the application of the OSS model, as listed here below:

Assignment of Intellectual Property Rights

OSS procurements can be applied within ESA in compliance with the principles set forth by the ESA Convention, the Rules concerning Information, Data and Intellectual Property, GCC and other internal procedures.

In general, OSS procurements can be implemented with the developer(s) of the software (original and derived products) retaining the IP. In certain cases, however, ESA might request the assignment of the IP according to the Open Source Clause 42.10 of the GCC, e.g. when no industrial leader can be identified.

ESA Open Source Software Repository

An OSS repository has been setup with the following purpose:

• guide European industry in identifying available OSS products within the European space domain;
• help European industry in joining ongoing OSS collective development projects;
• provide visibility on licensing schemes on European OSS products;
• support the build up of collaborative OSS initiatives.

This repository provides European space actors with information on OSS products for space, and associated licensing and legal aspects. It also supports the assessment of the maturity and verification status of OSS products, thereby facilitating the pre-selection of OSS products and services. The repository also features community forums to support collaborative efforts involving software developers and end-users.

The OSS repository helps to control the licensing of such software by ESA in a more centralized way in order to minimize risks of possible infringements. It also allows industry to have visibility of ESA and other European developments and contribute to the fulfilment of ESA’s mandate to spur European cooperation.

General Principles for selecting the OSS Model in ESA

The application of the OSS to ESA software developments shall be in line with the achievement of the following goals:

1. Maximise the efficiency in the procurement of software products for application in space programmes, i.e. saving costs and increase quality and innovation
2. Avoid excessive dependency on software suppliers where this poses a risk for the implementation of ESA programmes, i.e. avoiding lock-in situations
3. Minimise duplication of efforts in Europe, where no other benefit is achieved as per ESA Convention
4. Stimulate competition for proprietary software on the basis of innovation and added value features for the customer, rather than on standard features, for which a reliable and affordable supply already exists
5. Maximise the return on investment of software developments for the European space community at large, by providing, where appropriate, OSS alternative products in addition to supporting proprietary software products
6. Maximise the benefits from using already existing software available under an Open Source licence, as long as the licence conditions are acceptable and do not pose unnecessary risks for ESA, also in view of further licensing to third parties of the final products
7. Maximise the re-use of software products from mission to mission, where this leads to concrete savings and has no other draw-backs
8. Contribute to scientific initiatives based on sharing of OSS, where such contribution is in the interest of ESA and its Member States
9. Promote the widest possible use of standards, in particular those developed in partnership with industry and National agencies e.g. in the frame of ECSS, CCSDS, and whose adoption is essential for the efficiency of European space projects
10. Improve the quality of software products of interest for the European space sector by means of collective efforts as the ones typical for OSS communities
11. Open up market opportunities for European space industry in other industrial sectors
12. Help start-up companies and small and medium sized enterprises to establish themselves as software and service providers, where it is suitable for stimulating innovation
13. The OSS model is not meant to constitute the default option for software development under ESA contracts, but shall be considered for the application scenarios described above
14. ESA shall support the dissemination of information on existing OSS products applicable to space and the OSS repository shall support this objective
15. The application of the OSS scheme shall remain in line with the spirit of the GCC regarding the treatment of IP
16. Where no industrial leader can be identified, ESA can act as the agency coordinating the OSS community leaving space for industrial business cases to develop through OSS related maintenance and support services. In this case transfer of OSS IP to ESA can be implemented
17. In line with ESA’s mandate, the legitimate commercial interests of industry shall be respected
18. The procurement and use of OSS shall follow the quality standards and rules applicable for software reuse

Selection of the ESA Licence

The choice (or obligation) for a distributor to use a given type of OSS licence depends on whether existing software is re-used for the development and what constraints, if any, are imposed by the relative licensing conditions. Reflecting the characteristics of the various mainstream OSS licences, the ESA licences have been developed such that it can be configured to be:

Esa accommodates the above copyleft options through three different types of the ESA Public Licence (ESA-PL). The ESA-PL entails world-wide licensing in accordance with the basic principles of OSS.  However, in order to cater for situations where licensing is to be limited to the territory of the ESA Member States, ESA has developed the so-called ESA Software Community License (ESCL) which, although not qualifying as a proper OSS licence, implements the OSS principles to the maximum extent.  The ESCL accommodates the same copyleft options as the ESA-PL.

The applicable versions of the above ESA licences are available under https://essr.esa.int/license/list, and reflect the above copyleft options as follows: