OSI-approved, but the FSF calls it non-free and it does not combine with the GPL. Export control terms apply as well.
On this page
What it does
The NASA Open Source Agreement 1.3 is what NASA releases some of its software under, including parts of the World Wind and Core Flight System families. It is an agreement rather than a plain permission grant, and it reads like one. You may use, change and redistribute the code, including inside a commercial product. In return you keep the government notices and disclaimers, mark your changes, and identify yourself as the party who made them. You also make the changed source available under the same agreement and follow United States export control law.
Details
The fact a reviewer needs first is the classification. NASA-1.3 is approved by the Open Source Initiative, but the Free Software Foundation lists it as a non-free license, largely because it asks that your contributions be your original creation. It also does not combine with the GPL. That pairing can fail a customer's procurement policy even though the code is public and free of charge. The export control clause is the second surprise, because it binds you even when you never distribute, which is unusual in this family.
Pros
- You can link the library from closed code in the way the license describes.
- File-level reciprocity is easier to isolate than GPL-style whole-work copyleft.
Cons
- Vendoring or statically linking can pull more of your tree into the covered set than a dynamic link would.
- The source-offer duty is real the moment you distribute binaries that include modified covered files.
What it allows and requires
Choose a category to see the full grant in one scannable list. Permissions show what the license allows, limits show what it withholds, and obligations show the conditions your release process must satisfy.
Permissions
Commercial use
You may ship the code inside a paid product. The license does not restrict commercial use.
Modify
You may change the code, including keeping those changes private, unless a later obligation says otherwise.
Distribute
You may give copies to others. Distribution is what usually turns notice and source duties into real work.
Private use
Use inside your company, including internal forks, does not by itself trigger distribution duties.
Patent use
These licenses typically include a patent grant covering the licensed files. Read the grant before relying on it in a high-stakes deal.
Limits
Hold liable
The authors disclaim warranty. Recipients cannot hold them liable for damages arising from the software, except where law forbids that disclaimer.
Use trademark
The license is not a trademark license. Names, logos and product marks stay with their owners unless a separate grant says otherwise.
Open your product
File- or library-scoped copyleft does not, on its face, force you to open your entire application. Reciprocity stays on the covered files.
Obligations
Include copyright
Keep copyright notices on the covered files you distribute.
Include license
Keep the license text with the covered files, and say that those files are under this license.
Disclose source
Covered files you change and distribute must have source available under the same license.
What NASA-1.3 requires when you ship
When you distribute a binary that includes NASA-1.3 code, notice still travels with the copy, and the corresponding source has to be available under the same license. Internal use without a copy leaving the company is a different situation. The list below is the shipping work: what a recipient of that binary can demand, and what you record so a buyer can see it.
You are meeting the marking duty when every change you distribute is labeled as a change and names the person or organization that made it.
You are meeting the source condition when the source of your changed version is available under the same agreement to everyone who receives the binary.
You have handled the notices when the government disclaimers and the original notices stay in the files and travel with your distribution.
You have covered export control when someone has checked United States export rules for the countries you ship to, before the release goes out.
You stay clear of the endorsement problem when nothing in your product or marketing uses NASA's name or insignia to suggest support for it.
The duties named in NASA-1.3
Notice still travels with the copy. On top of that, NASA-1.3 names a source duty. These are the conditions in the text. The how-to above is when they become real work.
Include copyright
Keep copyright notices on the covered files you distribute.
Include license
Keep the license text with the covered files, and say that those files are under this license.
Disclose source
Covered files you change and distribute must have source available under the same license.
Things to be aware of
- A government release is assumed to be public domain. NASA-1.3 is an agreement with real conditions, so treat it as a licensed dependency like any other.
- The export clause is ignored because the code sits on a public website. Public availability is not an export decision, so ask before you ship abroad.
- A buyer's allow-list is answered with 'it is OSI-approved'. Say the whole thing, including the FSF position, so procurement is not surprised later.
What the NASA Open Source Agreement 1.3 does not do
Search results often flatten NASA Open Source Agreement 1.3 into a slogan. These are the usual misreads. NASA-1.3 is a grant with conditions, not a permission to skip the paperwork below.
- the NASA Open Source Agreement 1.3 does not force you to open your whole application. The reciprocal duty stays on the covered files.
- It is not "permissive with extra paperwork." Change a covered file and ship it, and that file's source has to be available under the same license.
How NASA-1.3 differs from nearby licenses
These licenses are often confused with NASA-1.3, but their release duties differ. Each row summarizes what the license requires when you ship. Open the linked page for the full checklist.
- NASA-1.3
- OSI-approved, but the FSF calls it non-free and it does not combine with the GPL. Export control terms apply as well.
- MPL-1.1
- The 1998 Mozilla license. Its source duty attaches to the files you modified, not to every MPL file you ship, and it has no GPL bridge.
- EPL-1.0
- The older Eclipse license. Same Contribution-scoped duty as EPL-2.0, but with no GPL bridge, so mixing with GPL code is a real problem.
- Apache-2.0
- Permissive like MIT, plus an express patent grant. The catch is the NOTICE file: it has to travel inside the binaries you ship.
Common questions about NASA Open Source Agreement 1.3
Answers to common questions about what NASA Open Source Agreement 1.3 requires, when its duties apply, and what evidence belongs with a release.
What is the NASA Open Source Agreement 1.3?
The NASA Open Source Agreement 1.3 is what NASA releases some of its software under, including parts of the World Wind and Core Flight System families. It is an agreement rather than a plain permission grant, and it reads like one. You may use, change and redistribute the code, including inside a commercial product. In return you keep the government notices and disclaimers, mark your changes, and identify yourself as the party who made them. You also make the changed source available under the same agreement and follow United States export control law.
What does NASA-1.3 require when you ship a product?
You are meeting the marking duty when every change you distribute is labeled as a change and names the person or organization that made it. You are meeting the source condition when the source of your changed version is available under the same agreement to everyone who receives the binary. You have handled the notices when the government disclaimers and the original notices stay in the files and travel with your distribution. You have covered export control when someone has checked United States export rules for the countries you ship to, before the release goes out. You stay clear of the endorsement problem when nothing in your product or marketing uses NASA's name or insignia to suggest support for it.
Does hosting a product that uses NASA-1.3 trigger extra duties?
Hosting alone usually does not trigger the source duty for NASA-1.3. Shipping a binary, a container, or an on-prem build does. Notice still travels with any copy you hand over.
Can I keep my application closed if I use NASA-1.3?
NASA-1.3 is library-scoped copyleft. Your application can stay closed if recipients can replace the library with their own build. Static linking makes that expensive. The library itself still ships with corresponding source and notices. Confirm the linking story on the component, then record it.
What is corresponding source for NASA-1.3?
Corresponding source is the source a recipient needs to build and run the same binary, including scripts and interface files the license names. Hosting a repository URL can be an offer. The offer has to match what you actually shipped. SourceTrust records that a person on your team confirmed the offer. It does not publish your source and does not host a mirror.
How is NASA-1.3 different from Mozilla Public License 1.1?
NASA-1.3 asks this: OSI-approved, but the FSF calls it non-free and it does not combine with the GPL. Export control terms apply as well. Mozilla Public License 1.1 asks this: The 1998 Mozilla license. Its source duty attaches to the files you modified, not to every MPL file you ship, and it has no GPL bridge. Open the Mozilla Public License 1.1 page for what that license requires when you ship. Do not treat the SPDX ids as interchangeable because the short names look similar.
Where do I record NASA-1.3 for a buyer?
NASA-1.3 has a catalog row marked copyleft, so a source offer item appears on the project checklist in the Distributed binary and Mixed contexts. There is no obligation item for export control or for the marking duty, so those stay with you and your counsel. What SourceTrust does carry is the stored license text, onto your attestation page and into every export file it generates from the published snapshot.
Where do I record NASA-1.3 for a buyer?
NASA-1.3 has a catalog row marked copyleft, so a source offer item appears on the project checklist in the Distributed binary and Mixed contexts. There is no obligation item for export control or for the marking duty, so those stay with you and your counsel.
What SourceTrust does carry is the stored license text, onto your attestation page and into every export file it generates from the published snapshot. Read /docs/export-sbom for the formats.
See also
The hub is the pillar for this cluster. Sibling licenses are the other spokes. Product FAQ links explain how SourceTrust records the duty, not the license text itself.
Practical guidance for procurement review, not legal advice. Confirm high-stakes use with counsel.