The NTRS is a valuable resource for researchers, students, educators, and the public to access NASA's current and historical technical literature and engineering results. Over 500,000 aerospace-related citations, over 200,000 full-text online documents, and over 500,000 images and videos are available. NTRS content continues to grow as new scientific and technical information (STI) is created or funded by NASA. The types of information found in the NTRS include: conference papers, journal articles, meeting papers, patents, research reports, images, movies, and technical videos. NTRS is Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) enabled

The National Space Science Data Center serves as the permanent archive for NASA space science mission data. 'Space science' means astronomy and astrophysics, solar and space plasma physics, and planetary and lunar science. As permanent archive, NSSDC teams with NASA's discipline-specific space science 'active archives' which provide access to data to researchers and, in some cases, to the general public. Search by event, spacecraft, experiment, map, or publication query. NSSDC is part of the Solar System Exploration Data Services Office (SSEDSO) in the Solar System Exploration Division at NASA's Goddard Space Flight Center in Greenbelt, MD.

The NASA Technical Standards Program provides access to NASA developed standards and handbooks. The NASA Standards and Technical Assistance Resource Tool, or START, is a Web tool sponsored by the NASA Technical Standards Program. The idea is to make it simpler for technical people to access great NASA technical information quickly and conveniently.

The National Aeronautics and Space Administration (NASA) Aerial Photography data set is a film archive of photographs from the Lyndon B. Johnson Space Center (JSC) in Houston, Texas, and the NASA Ames Research Center in Moffett Field, California. In 1965, the JSC initiated the Earth Resources Aircraft Program and began flying photographic missions for Federal Government agencies and other entities involved in remote sensing experiments. Beginning in 1966, NASA conducted an Earth Observations Program, including Earth surveys using aircraft platforms. Photographs from a variety of NASA programs provide project-specific coverage over the United States, Grand Bahama, Jamaica, and Central America at base scales ranging from 1:16,000 scale to 1:450,000 scale. Film types, scales, acquisition schedules, flight altitudes, and end products differ, according to project requirements.

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) (https://earthdata.nasa.gov/about/competitive-programs/measures) version SRTM, which includes the global 1 arc second (~30 meter) product. SRTMGL1_NUMNC is used along with the SRTMGL1_NC data product and offers the number count in NetCDF. NASA Shuttle Radar Topography Mission (SRTM) datasets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. The purpose of SRTM was to generate a near-global digital elevation model (DEM) of the Earth using radar interferometry. SRTM was a primary component of the payload on the Space Shuttle Endeavour during its STS-99 mission. Endeavour launched February 11, 2000 and flew for 11 days. SRTM collected data in swaths, which extend from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km). These swaths are ~225 km wide, and consisted of all land between 60° North (N) and 56° South (S) latitude. This accounts for about 80% of Earth’s total landmass.Improvements/Changes from Previous Versions * Voids in the Version 3.0 products have been filled with ASTER Global Digital Elevation Model (GDEM) Version 2.0, the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), and the National Elevation Dataset (NED).

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) (https://earthdata.nasa.gov/about/competitive-programs/measures) version SRTM, which includes the global 1 arc second (~30 meter) product. SRTMGL1_NC offers the data product in NetCDF. NASA Shuttle Radar Topography Mission (SRTM) datasets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. The purpose of SRTM was to generate a near-global digital elevation model (DEM) of the Earth using radar interferometry. SRTM was a primary component of the payload on the Space Shuttle Endeavour during its STS-99 mission. Endeavour launched February 11, 2000 and flew for 11 days. SRTM collected data in swaths, which extend from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km). These swaths are ~225 km wide, and consisted of all land between 60° North (N) and 56° South (S) latitude. This accounts for about 80% of Earth’s total landmass.Improvements/Changes from Previous Versions * Voids in the Version 3.0 products have been filled with ASTER Global Digital Elevation Model (GDEM) Version 2.0, the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), and the National Elevation Dataset (NED).

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) (https://earthdata.nasa.gov/about/competitive-programs/measures) SRTM, which includes the global 3 arc second (~90 meter) product. The 3 arc second data was derived from the 1 arc second using sampling and averaging methods. SRTMGL3_NC offers the data product in NetCDF.NASA Shuttle Radar Topography Mission (SRTM) datasets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. The purpose of SRTM was to generate a near-global digital elevation model (DEM) of the Earth using radar interferometry. SRTM was a primary component of the payload on the Space Shuttle Endeavour during its STS-99 mission. Endeavour launched February 11, 2000 and flew for 11 days. SRTM collected data in swaths, which extend from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km). These swaths are ~225 km wide, and consisted of all land between 60° North (N) and 56° South (S) latitude. This accounts for about 80% of Earth’s total landmass.Improvements/Changes from Previous Versions * Voids in the Version 3.0 products have been filled with ASTER Global Digital Elevation Model (GDEM) Version 2.0, the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), and the National Elevation Dataset (NED).

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) (https://earthdata.nasa.gov/about/competitive-programs/measures) SRTM, which includes the global 30 arc second (~1,000 meter) product. The NASA SRTM product with sample spacing of 3 arc second (~90 meter) generated by a 3 X 3 averaging of the 1 arc second data are then 10 X 10 averaged to produce thirty 30 arc second (~1,000 meter) data to correspond with Global 30 Arc Second Elevation (GTOPO30). (See the User Guide Section 2.1.4)The NASA SRTM data sets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. This collaboration aims to generate a near-global digital elevation model (DEM) of Earth using radar interferometry. SRTM was the primary (and virtually only) payload on the STS-99 mission of the Space Shuttle Endeavour, which launched February 11, 2000, and flew for 11 days.The SRTM swaths extended from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km), creating swaths ~225 km wide, and consisted of all land between 60 degrees N and 56 degrees S latitude to account for 80 percent of Earth’s total landmass.Known Issues* SRTMGL30 is Version 2.1 and has not been updated for the NASA SRTM V3.0 release as described in the User Guide.* Known issues in the NASA SRTM are described in the following publication:Rodriguez, E., C. S. Morris, and J. E. Belz (2006), A global assessment of the SRTM performance, Photogramm. Eng. Remote Sens., 72, 249–260. https://doi.org/10.14358/PERS.72.3.249Improvements/Changes from Previous Versions* Editing, spike and pit removal, waterbody leveling, and coastline definition.

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) (https://earthdata.nasa.gov/about/competitive-programs/measures) SRTM, which includes the global 1 arc second (~30 meter) swath (raw) image data product (See User Guide Section 2.2.1).The SRTM swath image data set consists of radar image files containing brightness values, as well as quality assurance (incidence angle) files for each of four overlapping sub-swaths that passes through a 1 degree by 1 degree tile. Data from each sub-swath is included as a separate file. Some files may contain only partial data; however, every image pixel acquired by SRTM is included in this data set.The NASA SRTM data sets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. This collaboration aims to generate a near-global digital elevation model (DEM) of Earth using radar interferometry. SRTM was the primary (and virtually only) payload on the STS-99 mission of the Space Shuttle Endeavour, which launched February 11, 2000, and flew for 11 days.The SRTM swaths extended from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km), creating swaths ~225 km wide, and consisted of all land between 60 degrees N and 56 degrees S latitude to account for 80 percent of Earth’s total landmass. Known Issues* Known issues in the NASA SRTM are described in the following publication:Rodriguez, E., C. S. Morris, and J. E. Belz (2006), A global assessment of the SRTM performance, Photogramm. Eng. Remote Sens., 72, 249–260. https://doi.org/10.14358/PERS.72.3.249Improvements/Changes from Previous Versions * Voids in the Version 3.0 products have been filled with ASTER Global Digital Elevation Model (GDEM) Version 2.0, the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), and the National Elevation Dataset (NED).