The following is a list of reference ESA open Software Licenses (original location at https://essr.esa.int/license/list)

Active ESA Licenses

These licenses cover the cases of real Open Source licenses (open to everybody) as well as Community Licenses (open to ESA member states only) with varying degree of copyleft.

Document Version Download Remark
European Space Agency Public License - Type 1 2.3   Strong Copyleft 
European Space Agency Public License - Type 2 2.3   Weak Copyleft 
European Space Agency Public License - Type 3 2.3   Permissive 
ESA Software Community License - Type 1 2.3    Strong Copyleft
ESA Software Community License - Type 2 2.3   Weak Copyleft 
ESA Software Community License - Type 3 2.3   Permissive 

Previously used ESA Licenses

Document Version Download Remark
European Space Agency Public License - Type 1 2.1  
European Space Agency Public License - Type 2 2.1 Does not allow relink
European Space Agency Public License - Type 2 2.1 Allows relink
European Space Agency Public License - Type 3 2.1  
ESA Software Community License - Type 1 1.1  
ESA Software Community License - Type 2 1.1 Does not allow relink
ESA Software Community License - Type 2 1.1 Allows relink
ESA Software Community License - Type 3 1.1  

Additional information