Peer-reviewed journal articles and juried conference papers, based wholly or partially on NSF support, must be deposited in the designated NSF repository. Either the final accepted version of the manuscript or the version of record may be submitted. NSF made the repository service available at the end of 2015 for voluntary compliance. In accordance with the applicable award terms and conditions, NSF "expects significant findings from research and education activities it supports to be promptly submitted for publication, with authorship that accurately reflects the contributions of those involved"
When a researcher authors a paper describing the results of research supported fully or partially by an NSF grant, there are steps that need to be taken to ensure that the paper is openly accessible to anyone who would like to read it or download it.
NSF requires that both manuscripts published in peer-reviewed journals as well as papers from conferences and meeting to be deposited in the NSF-Public Access Repository (NSF-PAR)
To meet the NSF requirements these works must:
The NSF mandates that funded researchers include data management plans when submitting applications for funding.
NSF funded projects are also expected to make make their data, produced as a result of the funding, freely available to other researchers.
Information about the policy can be found here