id string | title string | abstract string | date string | year int32 | sti_type string | center string | authors list | subjects list | rights string | ntrs_url string | pdf_url string | n_pages int32 | text string | pages string | n_suspect int32 | model string | cover image |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
19980235627 | Internal-Performance Evaluation of Two Fixed-Divergent-Shroud Ejectors | Ejectors designed for use in a Mach 2.2 aircraft were evaluated over a range of representative primary pressure ratios and ejector corrected weight-flow ratios. Basic thrust and pumping characteristics are discussed in terms of an assumed engine operating schedule to illustrate the variation of performance with Mach nu... | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Headquarters | [
"Mihaloew, James R."
] | [
"Aircraft Propulsion And Power"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19980235627 | https://ntrs.nasa.gov/api/citations/19980235627/downloads/19980235627.pdf | 34 | # TECHNICAL MEMORANDUM
## X-257
### INTERNAL-PERFORMANCE EVALUATION OF TWO FIXED-DIVERGENT-SHROUD EJECTORS
By James R. Mihaloev
Lewis Research Center
Cleveland, Ohio
---
**CLASSIFIED DOCUMENT - TITLE UNCLASSIFIED**
This material contains information affecting the national defense of the United States within the ... | [{"page": 1, "text": "# TECHNICAL MEMORANDUM\n\n## X-257\n\n### INTERNAL-PERFORMANCE EVALUATION OF TWO FIXED-DIVERGENT-SHROUD EJECTORS\n\nBy James R. Mihaloev\n\nLewis Research Center\nCleveland, Ohio\n\n---\n\n**CLASSIFIED DOCUMENT - TITLE UNCLASSIFIED**\n\nThis material contains information affecting the national def... | 0 | lightonocr-3-0.8b | |
19630003041 | INTERFERENCE EFFECTS AT TRANSONIC SPEEDS OF JETS EXHAUSTING FROM THE HULL STEP OF A MODEL OF A LARGE, WATER-BASED AIRPLANE | Interference of jet exhaust from large transonic seaplane | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Henry, B. Z., Jr."
] | [
"Biosciences"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19630003041 | https://ntrs.nasa.gov/api/citations/19630003041/downloads/19630003041.pdf | 35 | **NASA TM X-218**
# TECHNICAL MEMORANDUM
## X - 218
INTERFERENCE EFFECTS AT TRANSONIC SPEEDS OF JETS
EXHAUSTING FROM THE HULL STEP OF A MODEL
OF A LARGE, WATER-BASED AIRPLANE
By Beverly Z. Henry, Jr.
Langley Research Center
Langley Field, Va.
Declassified February 6, 1962
NATIONAL AERONAUTICS AND SPACE ADMINISTRA... | [{"page": 1, "text": "**NASA TM X-218**\n\n# TECHNICAL MEMORANDUM\n\n## X - 218\n\nINTERFERENCE EFFECTS AT TRANSONIC SPEEDS OF JETS\nEXHAUSTING FROM THE HULL STEP OF A MODEL\nOF A LARGE, WATER-BASED AIRPLANE\n\nBy Beverly Z. Henry, Jr.\nLangley Research Center\nLangley Field, Va.\n\nDeclassified February 6, 1962\n\nNAT... | 0 | lightonocr-3-0.8b | |
19630003077 | "EFFECTS OF GROSS LOAD AND VARIOUS BOW MODIFICATIONS ON THE HYDRODYNAMIC CHARACTERISTICS OF A HIGH-S(...TRUNCATED) | "Effect of gross load and bow modifications on hydrodynamic characteristics of subsonic mine- laying(...TRUNCATED) | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Kapryan, W. J."
] | [
"Biosciences"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19630003077 | https://ntrs.nasa.gov/api/citations/19630003077/downloads/19630003077.pdf | 35 | "**NASA TM X-71**\n\n554317 36P,5\nNASA TM X-71\n\nN63-12953\ncode-1\n\n# TECHNICAL MEMORANDUM\nX - (...TRUNCATED) | "[{\"page\": 1, \"text\": \"**NASA TM X-71**\\n\\n554317 36P,5\\nNASA TM X-71\\n\\nN63-12953\\ncode-(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19630004019 | "AN EXPERIMENTAL INVESTIGATION AT MACH NUMBERS FROM 2.1 TO 3.0 OF CIRCULAR INTERNAL-COMPRESSION INLE(...TRUNCATED) | Inlets having translatable centerbodies and provision for boundary layer removal | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Watson, E. C."
] | [
"Aircraft"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19630004019 | https://ntrs.nasa.gov/api/citations/19630004019/downloads/19630004019.pdf | 30 | "**CONFIDENTIAL** NASA TM X-156\n\nClassification changed to declassify effective 1 April 1963 under(...TRUNCATED) | "[{\"page\": 1, \"text\": \"**CONFIDENTIAL** NASA TM X-156\\n\\nClassification changed to declassify(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19650003094 | "Some effects of control profile and control trailing-edge angle on the oscillating hinge-moment and(...TRUNCATED) | "Hinge moment and flutter characteristics of flap- type controls - free oscillation tests of changes(...TRUNCATED) | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Gainer, T. G.",
"Moseley, W. C., Jr."
] | [
"Structural Mechanics"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19650003094 | https://ntrs.nasa.gov/api/citations/19650003094/downloads/19650003094.pdf | 69 | "Copy 573\n\nNASA TM X-170\n\nX62-7/94\n\n# TECHNICAL MEMORANDUM\n## X-170\n\nSOME EFFECTS OF CONTRO(...TRUNCATED) | "[{\"page\": 1, \"text\": \"Copy 573\\n\\nNASA TM X-170\\n\\nX62-7/94\\n\\n# TECHNICAL MEMORANDUM\\n(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19650003090 | "Force, moment, and flow-field characteristics of two wing-body-nacelle combinations at mach numbers(...TRUNCATED) | "Force, moment, and flow field characteristics of two wing body nacelle combinations at Mach 2 and 3(...TRUNCATED) | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Hill, W. A., Jr."
] | [
"Aerodynamics"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19650003090 | https://ntrs.nasa.gov/api/citations/19650003090/downloads/19650003090.pdf | 92 | "**TECHNICAL MEMORANDUM**\n\nX-III\n\nFORCE, MOMENT, AND FLOW-FIELD CHARACTERISTICS OF TWO WING-BODY(...TRUNCATED) | "[{\"page\": 1, \"text\": \"**TECHNICAL MEMORANDUM**\\n\\nX-III\\n\\nFORCE, MOMENT, AND FLOW-FIELD C(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19660024051 | "Performance evaluation of a two-stage turbine designed for a ratio of blade speed to jet speed of 0(...TRUNCATED) | "Efficiency evaluation of two-stage turbine with low ratio of blade to jet speed suitable for bleed-(...TRUNCATED) | 1960-01-01T00:00:00.0000000+00:00 | 1,960 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Kofskey, M. G."
] | [
"Propulsion Systems"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19660024051 | https://ntrs.nasa.gov/api/citations/19660024051/downloads/19660024051.pdf | 36 | "**NASA TM X-146**\n\nGPO PRICE $\nCFSTI PRICE(S) $\nHand copy (HC)\nMicrofiche (MF)\n\n---\n\n# TEC(...TRUNCATED) | "[{\"page\": 1, \"text\": \"**NASA TM X-146**\\n\\nGPO PRICE $\\nCFSTI PRICE(S) $\\nHand copy (HC)\\(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19690006771 | I-123 production by the Sb-121 /alpha, 2n/ I-123 method | "Cyclotron technique for producing high purity iodine 123, and procedures for isolating iodine produ(...TRUNCATED) | 1969-01-01T00:00:00.0000000+00:00 | 1,969 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Blue, J. W.",
"Sodd, V. J."
] | [
"Biosciences"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19690006771 | https://ntrs.nasa.gov/api/citations/19690006771/downloads/19690006771.pdf | 17 | "**NASA TECHNICAL MEMORANDUM**\n\nNASA TM X-52534\n\n**CASE FILE COPY**\n\n**CAS COPY**\n\n**123I PR(...TRUNCATED) | "[{\"page\": 1, \"text\": \"**NASA TECHNICAL MEMORANDUM**\\n\\nNASA TM X-52534\\n\\n**CASE FILE COPY(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19690006039 | "Empirical characterization of some pressure wave shapes in strong traveling transverse acoustic mod(...TRUNCATED) | Harmonic content of pressure wave shapes in strong traveling transverse acoustic modes | 1969-01-01T00:00:00.0000000+00:00 | 1,969 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Heidmann, M. F."
] | [
"Fluid Mechanics"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19690006039 | https://ntrs.nasa.gov/api/citations/19690006039/downloads/19690006039.pdf | 13 | "**NASA TECHNICAL MEMORANDUM**\n\n**NASA TM X-1716**\n\n**CASE FILE COPY**\n\n---\n\n**EMPIRICAL CHA(...TRUNCATED) | "[{\"page\": 1, \"text\": \"**NASA TECHNICAL MEMORANDUM**\\n\\n**NASA TM X-1716**\\n\\n**CASE FILE C(...TRUNCATED) | 0 | lightonocr-3-0.8b | |
19690007457 | Mean gradient heat transfer in isotropic turbulence Progress report | Mean temperature gradient heat transfer in isotropic turbulence | 1969-01-01T00:00:00.0000000+00:00 | 1,969 | TECHNICAL_MEMORANDUM | Legacy CDMS | [
"Hill, J. C."
] | [
"Thermodynamics And Combustion"
] | GOV_PUBLIC_USE_PERMITTED | https://ntrs.nasa.gov/citations/19690007457 | https://ntrs.nasa.gov/api/citations/19690007457/downloads/19690007457.pdf | 30 | "# General Disclaimer\n\n## One or more of the Following Statements may affect this Document\n\n- Th(...TRUNCATED) | "[{\"page\": 1, \"text\": \"# General Disclaimer\\n\\n## One or more of the Following Statements may(...TRUNCATED) | 0 | lightonocr-3-0.8b |
NASA Technical Reports (NTRS) — modern OCR of the Apollo-era archive

9,000 public NASA technical documents (498,206 pages, 1960–1975) from the NASA Technical Reports Server (NTRS), re-transcribed page by page with lightonocr-3-0.8b, a vision-language OCR model. Tables come out as HTML tables, equations and Greek symbols as Unicode/LaTeX, and headings as Markdown. NASA's own full-text files are not redistributed here (NASA asks that people link to the NTRS record instead), so every row links to its authoritative NTRS citation.
Useful for: pretraining and fine-tuning on technical and scientific text, OCR benchmarking , retrieval and RAG over aerospace history, Apollo/Space Race research, and document-understanding work.
Quick start
from datasets import load_dataset
ds = load_dataset("rwitz/nasa-ntrs-ocr", split="train")
row = ds[0]
print(row["title"], row["year"], row["ntrs_url"])
print(row["text"][:1000]) # new OCR, Markdown
row["cover"] # first-page thumbnail (PIL image)
Rights, provenance and what was included
Only documents NASA marks as publicly distributable were used, and only NASA's own report series. Each document was kept only if its NTRS record satisfied all of the following (checked automatically from the record's metadata at crawl time):
- Distribution:
PUBLIC(nothing restricted, no CUI, no export control). - Copyright determination:
GOV_PUBLIC_USE_PERMITTED("Work of the US Gov., public use permitted"). - Not flagged as owned by a contractor, author or publisher, and no third-party material.
- Document type is one of NASA's own series: Technical Memorandum, Technical Note, Technical Report, Technical Publication, Special Publication.
- A PDF is attached.
Deliberately excluded: contractor reports, journal reprints, conference papers, translations of foreign works,
anything with an OTHER or any non-government rights label, and anything not PUBLIC.
NASA's terms state that its documents are not protected by copyright unless
noted and may be reproduced and distributed without further NASA permission, while contractor/third-party works
may be copyrighted. The filter above is designed to keep only the former. Every row carries its rights label and a
link (ntrs_url) to the authoritative NTRS record so each item can be verified.
Attribution: Data provided by NASA Scientific and Technical Information Program (https://ntrs.nasa.gov/api/openapi/). NASA is the source of the underlying documents. This dataset is not produced, endorsed or reviewed by NASA, and NASA names/logos are not used to imply endorsement. Opinions in the documents are the authors'.
License of this dataset: the OCR text, metadata and derived fields added here are released under CC0 1.0. The underlying documents are works of the US Government as labelled by NASA. This is a good-faith compliance effort, not legal advice. NTRS rights labels on older records were migrated in bulk, so occasional mislabels are possible.
Availability changes: NASA's Redistributions endpoint is checked at least weekly. Records NASA withdraws or restricts are removed from this dataset.
Takedown / corrections: if you believe any item should not be here, open a discussion on this dataset's
Community tab with the id and it will be removed promptly.
Contents
| Column | Description |
|---|---|
id |
NTRS document ID |
title, abstract, date, year, sti_type, center, authors, subjects |
NTRS metadata |
rights |
NTRS copyright determination (always GOV_PUBLIC_USE_PERMITTED) |
ntrs_url, pdf_url |
Source record and original PDF |
text |
New OCR of the whole document (Markdown/HTML tables), pages joined |
pages |
JSON list of {page, text, flags} per page |
n_pages, n_suspect |
Page count; pages flagged as possibly bad (hit token limit or looped) |
cover |
First-page thumbnail |
model |
OCR model used |

How it was made
- Crawled the NTRS search API month by month and applied the rights filter above.
- Downloaded each PDF, rendered every page (longest edge 1540 px) and ran lightonocr-3-0.8b locally through LM Studio.
- Cleaned output (dropped figure placeholders and model captions, retried loops), kept per-page flags.
Pipeline code: see the repository files ntrs_crawl.py, ntrs_ocr.py, sync.py.
Limitations
- OCR is machine output and unverified. Handwriting, dense fold-out tables, and pages that are mostly figures are the weakest cases. Figures are not transcribed; captions are.
- Page 1 of each document is stored as a small thumbnail only. Full page images are not included; use
pdf_url. - Some pages may have errors, dropped or reordered text; check
n_suspectandpages[].flags.
Citation
@dataset{ntrs_lightonocr_ocr,
title = {NASA Technical Reports (NTRS) OCR, Apollo era},
author = {rwitz},
year = {2026},
url = {https://huggingface.co/datasets/rwitz/nasa-ntrs-ocr},
note = {Source documents: NASA Technical Reports Server, https://ntrs.nasa.gov/}
}
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