[License-review] Resubmission of the European Space Agency Public Licenses (ESA-PL) for approval

Thu Apr 23 15:28:55 UTC 2026

Dear Carsten,

It is not correct that the last communication from OSI about these 
licenses was in 2018. When I was chair of the License Committee, 
succeeding Richard Fontana, I followed up on them in October 2019 but 
received no response. You can see the follow up messages at:

https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2019-October/004434.html
https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2019-October/004437.html
https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2019-October/004435.html
https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2019-October/004436.html
https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2019-October/004441.html
https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2019-December/004450.html

Pamela S. Chestek
Chestek Legal
4641 Post St.
Unit 4316
El Dorado Hills, CA 95762
+1 919-800-8033
pamela at chesteklegal.com
www.chesteklegal.com

On 4/23/2026 4:10 AM, Carsten Gerlach wrote:
> Dear OSI board members and license reviewers,
>
> please allow me to re-submit on behalf of the European Space Agency
> (ESA) the European Space Agency Public Licenses (ESA-PL) v2.5 for OSI
> approval.
>
> The licenses have already been submitted to the license-review mailing 
> list in 2016 and 2018. Both times ESA took into account the comments 
> received and made updates to the license text. Unfortunately the 
> review process stalled. The last communication on the license-review 
> mailing list was a status update posted by Richard Fontana on 12 
> November 2018, where it was stated that "with at most some limited 
> changes the licenses would be ready for approval" 
> (https://lists.opensource.org/pipermail/license-review_lists.opensource.org/2018-November/003822.html).
>
> The licenses are actively used within the European space industry for 
> open source projects. You can find some of these projects in ESA's 
> public European Space Software Repository at https://essr.esa.int/.
>
> There are three versions of the ESA-PL licenses, each with a different
> Copyleft scope, but otherwise identical provisions:
> - ESA-PL Strong: a strong Copyleft license, with the Copyleft scope
> comparable to the GPL/AGPL,
> - ESA-PL Weak: a weak Copyleft license, with the Copyleft scope
> comparable to the MPL,
> - ESA-PL Permissive: a non-Copyleft license.
>
> Please find the license text attached as a plaintext copy and as a
> formatted PDF.
>
> Rationale and proliferation category have not changed since the first
> submission for review in 2016:
>
> 1. Rationale for a new license
>
> Software development is of key importance for ESA. Through its
> industrial contracts and internal activities, ESA strives to maintain
> and increase its technical know-how and leadership regarding software
> development for space related applications and activities.
>
> One of the challenges taken on board by ESA is the use and promotion of
> Open Source Software (OSS) in addition to software licensed in more
> traditional ways. Most development projects either use OSS components or
> are themselves already distributed under an OSS license. ESA wishes to
> support OSS and community-based development approaches in a way
> compatible with its mandate and overall legal framework.
>
> The ESA-PL licenses are primarily intended to be used by ESA or ESA
> contractors for providing inhouse developments or industrial
> developments under ESA contracts to the general public as Open Source
> software. Depending on the use case and the rationale behind the
> publication, either a Copyleft or a Permissive license type may be
> appropriate.
>
> The need for an ESA-specific Open Source license is primarily resulting
> from the special legal framework by which ESA is bound, in particular
> the ESA Convention and ESA's intellectual property (IPR) rules. The ESA
> Convention requires in particular that the applicable law has to be the
> law of an ESA Member State and that the license includes an arbitration
> clause in accordance with the ESA Convention. Such provisions are not
> found in existing OSS licenses. The choice of law necessitates a
> particular wording of the license grant and the warranty and liability
> clauses (please see the attached license commentary for more details).
>
>
> 2. Distinguish - compare to and contrast with the most similar
> OSI-approved license(s)
>
> There are three versions of the ESA-PL licenses, each with a different
> Copyleft scope, but otherwise identical provisions:
> - ESA-PL Strong: a strong Copyleft license, with the Copyleft scope
> comparable to the GPL/AGPL,
> - ESA-PL Weak: a weak Copyleft license, with the Copyleft scope
> comparable to the MPL,
> - ESA-PL Permissive: a non-Copyleft license.
>
>
> 3. Legal review
>
> The licenses were drafted by lawyers specialized in information
> technology and Open Source licensing law. As a result, the licenses were
> already drafted with the OSI Open Source definition in mind and are
> intended to comply with the OSI requirements. The licenses have been
> subject to review by ESA's legal department and licensing boards.
>
> Feedback from the OSI's license-review mailing list from 2016 and 2018 
> has been taken into account and is reflected in the submitted version 
> (2.4) of the licenses.
>
>
> 4. Proliferation category
>
> We recommend the licenses to be categorized as "Special Purpose
> Licenses", as the licenses meet the special needs of the ESA as an 
> international non-governmental organization. The license are well 
> established within the European space industry and are actively used 
> for open source projects (see e.g. https://essr.esa.int/).
>
>
> We hope that the licenses meet the criteria for OSI approval and
> the scrutiny of the review community. Please let us know if there are
> any questions, comments or suggestions.
>
> Kind regards
> Carsten Gerlach
>
>
> _______________________________________________
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>
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