The National Advisory Committee for Aeronautics (NACA) and after 1958, its successor, the National Aeronautics and Space Administration (NASA), published a variety of technical documents. In the AEHS collection, most NACA/NASA technical publications are in series I, but some are in other series, based on subject matter.

Here is a general description of the different types of NACA technical publications in the AEHS collection:

• "NACA Reports - NACA reports were considered to be the final and complete documentation on a subject or project and they often superceded one or more other NACA publication types. NACA Reports are sometimes (erroneously) referred to as 'NACA Technical Reports.'

• NACA Technical Notes (TNs) - Technical Notes were the basic unit of the research report series. Some early TNs were translations of foreign works.

• NACA Technical Memorandums (TMs) - TMs are translations of foreign works. The TM series probably replaced translations in the TN series.

• NACA 'Wartime Reports' - Reports produced specifically for World War II research, they were declassified after the conflict. Due to their urgent nature, they frequently received little editing when written, and no editing was done after they were declassified. The moniker "Wartime Reports" was added when they were declassified; previously they were issued as Advance Confidential Reports (ACRs), Advance Restricted Reports (ARRs), Restricted Bulletins (RBs) and Confidential Bulletins (CBs).

• NACA Research Memorandums (RMs) - RMs were initially restricted, and represented initial or limited scope results, and thus received less editing and preparation than other report series." [source: NASA TM-1999-209127, Apr 1999, pg 3]

The Iowa State University Library added further detail:

"Technical Notes (TN) - Report partial results or material of narrower interest. Selected information from these reports was often analyzed and refined for later publication in the more formal Report series.

Research Memorandum (RM) - Less formal reports issued to meet the need for rapid dissemination of aeronautical information.

[source: https://instr.iastate.libguides.com/c.php?g=49459&p=318692, accessed 1 July 2025]

Starting 1 Oct 1958, NASA took over for NACA. NASA continues to publishe a variety of technical documents, which it describes as follows:

Technical Publications (including Technical Notes (TN), Technical Papers (TP) & Technical Reports (TR) -- "Reports of completed research or a major significant phase of research that present the results of NASA programs and include extensive data or theoretical analysis. Includes compilations of significant scientific and technical data and information deemed to be of continuing reference value. NASA counterpart of peer-reviewed formal professional papers, but having less stringent limitations on manuscript length and extent of graphic presentations.

Technical Memorandum (TM) -- "Scientific and technical findings that are preliminary or of specialized interest, e.g., quick release reports, working papers, and bibliographies that contain minimal annotation. Does not contain extensive analysis.

Contractor Report (CR) -- "Scientific and technical findings by NASA-sponsored contractors and grantees."

Conference Publication (CP) -- "Collected papers from scientific and technical conferences, symposia, seminars, or other meetings sponsored or co-sponsored by NASA"

Special Publication (SP) -- "Scientific, technical, or historical information from NASA programs, projects, and missions, often concerned with subjects having substantial public interest."

Technical Translation (TT) -- "English-language translations of foreign scientific and technical material pertinent to NASA's mission."

[source: NASA TM-1999-209127, April 1999].