Find STI

Discover ways to find, locate, and access publicly available NASA STI. This page contains information about the NASA Technical Reports Server (NTRS), NTRS News information, harvesting NASA STI, and links to other STI resources.

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About NASA Technical Reports Server (NTRS)
NASA Technical Reports Server (NTRS) provides access to aerospace-related citations, full-text online documents, and images and videos. The types of information include: conference papers, journal articles, meeting papers, patents, research reports, images, movies, and technical videos – scientific and technical information (STI) created or funded by NASA.

By maintaining the NTRS collection, the STI Program supports NASA’s strategic goals to:

  1. Expand the frontiers of knowledge, capability, and opportunity in space.
  2. Advance understanding of Earth and develop technologies to improve the quality of life on our home planet.
  3. Serve the American public and accomplish our Mission by effectively managing our people, technical capabilities, and infrastructure.

The NTRS integrates the following three NASA collections and enables search and retrieval through a common interface:

  • NACA Collection: Citations and reports from the National Advisory Committee for Aeronautics period lasting from 1915 to 1958.
  • NASA Collection: Citations and documents created or sponsored by NASA starting in 1958 and continuing to the present.
  • NIX Collection: Citations and links to the images, photos, movies, and videos from the discontinued NASA Image eXchange (NIX).

Please see NASA Disclaimers, Copyright Notice, and Terms and Conditions of Use for information on how to use NASA’s scientific and technical information.



January 16, 2015   Updated STI Contact Information

The new STI address is:
NASA STI Program
STI Support Services

Mail Stop 148
NASA Langley Research Center
Hampton, VA 23681-2199
Fax: 757-864-6500

Information Desk is: or

September 13, 2013   Updates to RSS and Twitter Notices on New Content Frozen

Due to an on-going, major system transition, no new documents are currently being added to the NTRS. The RSS feed and Twitter updates about new content to NTRS will resume by mid-November.

September 10, 2013   Update to June 5, 2013 Questions and Answers on NTRS

On September 6, 2013, after export control analysis, nearly 138K documents were reloaded to the NASA Technical Reports Server (NTRS). This action more than doubles the full-text STI content available from NTRS and represents 75% of the full-text available prior to the NTRS going off-line in March 2013. The STI Program Office, in conjunction with the Export Control Program, will continue to assess the remaining content and release documents deemed publicly available.

June 15, 2013   The NASA Technical Reports Server (NTRS) has received an update!

The update provided:

  • A new fresh, clean look for users
  • Enhanced record display that shows author affiliations, sponsorship, and document type
  • A new Search History display that lists all searches conducted during a search session, and allows users to quickly recall a previous search for display or further refinement
  • Ability to search organization names from the advanced search form
  • Ability to flag multiple records of interest from a search-results display, and create a new set containing the flagged items

June 5, 2013   Questions and Answers on NTRS


On March 20, 2013, the NASA Administrator directed that the NASA Technical Reports Server (NTRS) be taken off-line while the Agency conducted a review of whether there is a risk of export-controlled documents being made available on the NTRS website. During this review, NASA provided the following public notice:
“The NASA technical reports server will be unavailable for public access while the agency conducts a review of the site’s content to ensure that it does not contain technical information that is subject to U.S. export control laws and regulations and that the appropriate reviews were performed. The site will return to service when the review is complete. We apologize for any inconvenience this may cause.”
Across the succeeding weeks, teams of personnel from the NASA Center for AeroSpace Information (CASI) and NASA Scientific and Technical Information Program Office (STIPO) have validated approximately 966,460 documents and metadata records from the NASA Technical Reports Server (NTRS) to ensure that all have received proper review and approval for public release, including required export control reviews for those NTRS records that comprise scientific and technical information. On May 8, 2013, the NTRS was brought back on-line for public access, reloaded with the validated 966,460 documents and metadata records. A small subset of approximately 248,000 documents, largely consisting of older documents, such as National Advisory Committee on Aeronautics materials, remain to be reviewed and will not be restored to public access until a thorough review is completed.

Responses to Questons:

  1. Why was the technical reports server taken down?

    Between March 20, 2013, and May 8, 2013, the NASA Technical Reports Server was unavailable for public access while the Agency conducted a review of the site’s content to ensure that the appropriate reviews were performed and that it does not contain technical information subject to U.S. export control laws and regulations.

  2. Why has NASA now brought the technical reports server back-up?

    On May 8, 2013, the NASA Technical Reports Server was brought back on-line for public access after the review and confirmation of approximately 966,460 records, images, and documents as having been properly screened and certified for public release.

  3. How many records have been reviewed and certified for posting on the technical reports server? How many have yet to be reviewed and certified for return to the technical reports server? When will they be posted?

    As of May 8, 2013, the NASA Technical Reports Server contains more than 966,460 records, images, and documents for public research purposes. A subset of approximately 248,000 documents, largely consisting of older documents, including National Advisory Committee on Aeronautics (NACA) materials, remain to be reviewed, and they will be loaded back to the NASA Technical Reports Server as soon as the reviews are completed by the originating NASA Centers.


Harvesting Data from NTRS
NTRS promotes the dissemination of NASA STI to the widest audience possible by allowing NTRS information to be harvested by sites using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). OAI-PMH defines a mechanism for information technology systems to exchange citation information using the open standards HTTP (Hypertext Transport Protocol) and XML (Extensible Markup Language). NTRS is designed to accept and respond to automated requests using OAI-PMH. Automated requests only harvest citation information and not the full-text document images.

If you are interested in harvesting from NTRS, please fill out the brief OAI Harvester Information form so that the STI Program can notify you of any changes related to the OAI service or content. Also note the changes to the available record formats below.

Sites interested in harvesting from NTRS should review the following guidance before harvesting:

Use of Government Information
The NTRS serves out unlimited, unclassified, publicly available NASA citations and full-text documents (PDFs). Persons, organizations, and sites interested in obtaining NASA information should review Disclaimers, Copyright Notice, Terms and Conditions of Use for guidance.

Harvesting Images
NTRS actively blocks spidering, robots, and intelligent agents from automatically retrieving the full-text images. Links to full-text documents (PDFs) are included in the citations. The URL image link in the harvested NTRS metadata is a way for your users to access the full-text document image residing on NTRS.

Harvesting Metadata Citations

  • The NTRS is an OAI-compliant data provider. OAI-PMH is an implementation of the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH), a standard for retrieving metadata from digital document repositories.
  • NTRS supports OAI-PMH version 2.0. It does not support earlier versions of the protocol.
  • The base URL for the NTRS is
  • An OAI request for harvesting from NTRS will return a maximum of 100 records per request. If you plan on harvesting more than 100 records, please run those requests between 8PM-8AM U.S. Eastern Time. Do not make more than one request every 3 seconds.
  • Users can harvest the NTRS data by sending an OAI compliant request to the NTRS archive. The request URL is formatted as (where XXX is the verb value). There are several valid verb values that provide useful information.
    Identify = Provides a description of the NTRS repository
    ListMetadataFormats = Gives the metadata format(s) available for request from NTRS
    ListSets = Provides a list of the NTRS defined sets. These results can help refine your request by asking for one specific set of data versus the entire NTRS collection
    ListIdentifiers = Gives a list of the OAI unique identifiers available within NTRS
    ListRecords = Gives a listing of N records at a time. NTRS is currently set to give 100 records at a time with a Resumption Token at the end if more records are available for the request received
    GetRecord = Will provide the user the XML file for a specific record
  • Records may be harvested from NTRS in the following formats: oai_dc and casi_dc — a more inclusive record format based on Dublin Core and supplemented with NASA terms. For more information, see the field description document for the casi_dc format, and the schema references returned from the following request:

Updated, Modified, and Deleted Citations and Full-Text Documents
Over time, metadata citations and full-text document images may be updated, modified, and/or deleted as a result of regular data management. The best method to detect changes in NTRS information is regular harvesting of NTRS using OAI-PMH. Newly updated and/or modified records will automatically replace previously harvested records. Records marked as ‘deleted’ will take additional processing on your site to detect NASA citations that should be deleted from your repository.


Related Content
The following links provide resources for users who would like to find more information from NASA and beyond. These links open in a new window.