In 2022, the Landsat series of satellites, a program conducted jointly by the U.S. Geological Survey and NASA, celebrates a half century of worldwide Earth observations for the good of humankind.
Fifty Years of Landsat: Sharing Earth information for the benefit of all
Part Two of a Six-Part Series Highlighting the 50th Anniversary of Landsat
Since its inaugural launch on July 23, 1972, the Landsat satellite series has drawn the world’s longest and most comprehensive portrait of our planet – from 400 miles in space – that stretches across five decades of time. This unique and priceless data set enables scientists and analysts around the globe to detect and monitor critical changes in the Earth’s landscapes, surface waters, and coastal ecosystems.
A central reason for the ongoing success of the Landsat mission has been its consistent practice of sharing Landsat data and insights about the Earth and its resources with a wide international audience.
The origin of Landsat
In 1965, USGS Director William Pecora proposed the idea of a remote sensing satellite program to gather facts about the natural resources of our planet with technology that was both more thorough and less expensive for large areas than conventional aerial photography. The concept generated intense budgetary and technical debates over funding sources and the advantages of either airplane or satellite platforms for remote sensing. Additionally, there were serious geopolitical concerns about photographing foreign countries without their express permission.
Then-Secretary of the Interior Stewart Udall boldly announced in a September 1966 press release that the U.S. Department of the Interior was launching "Project EROS” (Earth Resources Observation Satellites) to collect invaluable information about Earth through remote sensing by satellites. This remarkably ambitious project, later renamed Landsat, supported the mandate that Congress set for the USGS when the agency was established in 1879: “...classification of the public lands, and examination of the …products of the national domain.” Secretary Udall’s further vision was "to observe the Earth for the benefit of all," a clear reference to the concept of the peaceful international use of outer space that was championed by the U.S. and subsequently established in a 1967 United Nations treaty.
A network for shared knowledge from the start
In Landsat’s early years, technology limitations prevented global data transmission from the satellite to a centralized data storage facility. Rather, the Landsat program depended on a network of International Cooperators to operate International Ground Stations around the world that had direct line-of-site downlink capabilities [historical map]. These stations preserved the data collected for their global region and then relayed it back to the USGS Earth Resources Observation and Science Center in Sioux Falls, S.D. To date, the IGSs’ data comprises more than 65% of the entire USGS Landsat global data archive.
The IGSs were free to use the data they collected as they wished. This policy embodied U.S. support for the peaceful use of outer space and the worldwide dissemination of civil space technology to improve societal decisions at all levels of government. As an example of this technical and diplomatic outreach, in December 1976, only four years after Landsat 1 launched, remote sensing experts from USGS-EROS held their first Latin American remote sensing course in Buenos Aires, Argentina. Thirty-four students representing nearly all Earth science disciplines participated.
Today 18 actively operating IGSs span 12 countries around the world*, each providing an essential dimension to the Landsat mission. The reception capabilities of each station augment the global data collection capacity of the Landsat system via the Landsat Ground Network.
Free data for all sparks innovation
New and previously unimaginable Landsat applications were fostered by a policy change in 2008 that made Landsat data freely available to the global community. Early that year, USGS, NASA and DOI officials approved a Landsat Data Distribution Policy that made the satellite’s images free to the public. The USGS announced the free-and-open data policy on April 21.
In the past, financial and technical constraints prevented scientists from obtaining all available Landsat data for a single location to study its change through time. Since 2008, not only have individual users had free access to specific Landsat data and imagery, but open public access has encouraged geospatial and data processing firms, such as Amazon, Esri, Google, and Microsoft, to host the entire massive Landsat archive and to develop advanced access, retrieval, and visualization applications for the data. One theme of these highly developed applications is to rapidly compare change over time using temporal layers of Landsat data in a particular place or over broader regions. In recent years, with the development of cloud computing, massive amounts of data can now be processed in hours instead of months.
"The universal availability of the Landsat data at no charge is a key to its unique capabilities and global scope," said Anne Castle, former DOI Assistant Secretary for Water and Science, in a 2011 press release that now has a prescient ring. "Scientists, land managers, and students everywhere can work with long term, accurate, unbiased, and freely accessible data to confront the most difficult challenges involving land use, natural resources, and the environment.”
Landsat plays well with others
Thanks in large part to its Landsat assets and its related land remote sensing science and applications work, USGS plays a leadership role in several international groups for satellite observations. Two notable examples are the Committee on Earth Observation Satellites and the International Charter for Space and Major Disasters .
CEOS is a voluntary international partnership of 52 space agencies and related organizations, which work to enhance international coordination of satellite observations and data exchange for societal benefit. Through its participation in CEOS, USGS is positioned to advance space-based land remote sensing technologies and applications with foreign partners, to obtain new data sets, and to serve the science and technology needs of its user community. The International Charter is composed of space agencies and space system operators from around the world who work together to provide satellite imagery for disaster response and mitigation purposes. The USGS contributes Landsat imagery and data as needed as well as other government and commercial disaster-relevant imagery that can be accessed via USGS EROS.
Sharing is best as the world becomes more complex
In 2010, the European Commission and European Space Agency made the decision to make their Copernicus Sentinel imagery freely and openly available to the public. The 2015 Copernicus Cooperation Arrangement between the EC and the U.S. State Department has enhanced U.S. access to Copernicus Sentinel data. U.S. and European agencies are now collaborating to advance remote sensing innovation, improve satellite data quality, and enhance satellite mission data compatibility. Broad user demand for Landsat and Copernicus Sentinel-2 data has led USGS, the EC, and ESA to better coordinate their mission parameters, harmonize their datasets, and develop innovative new joint data products which improve temporal coverage.
The multibillion-dollar benefits of Earth imagery are enhanced by this combined effort. A collaboration of imaging our planet among nations means that each party maintains national capabilities but also has more frequent and improved images available without undue burden to taxpayers in any one nation. Since the data sharing by governments is increasingly free and open, countless other users from commercial, private, academic, and non-profit sectors can use it to provide new decision-support services for disaster preparedness, environmental protection, sustainable development, and climate change mitigation.
Sharing for the future
The future of Landsat looks bright, with Landsat 8 and 9 in orbit, and the Landsat Next mission in its final design phases. NASA and USGS are currently reviewing the findings from a joint Architecture Study Team, which will inform the design and implementation approach for Landsat Next, the follow-on mission to Landsat 9. Landsat Next, which is currently planned for a launch in the late 2020s, will provide improved spatial and spectral resolution, with its data being backward-compatible with the 50-year Landsat archive.
Note - “Spectral bands” refers to the wavelengths of light that Landsat instruments measure. Landsats 8 and 9 measure 11 spectral bands from the visible to thermal infrared wavelengths. The goal for Landsat Next is to measure up to 25 spectral bands.
Landsat Next will enable many new applications and enhance existing ones, such as monitoring surface water quality, contributing to cryospheric science and geology, assessing agricultural crop water consumption, and enabling improved estimation of surface temperatures. Of course, data interoperability and continuing international cooperation will also remain crucial priorities for USGS.
Sharing Earth information for the benefit of all will be central to the future of Landsat, as it was at the beginning and has been for 50 years.
The Landsat Program, a joint mission of the U.S. Geological Survey and NASA, has provided continuous global coverage of landscape change since 1972. Landsat’s unique l50 year data record provides the basis for a critical understanding of environmental and climate changes occurring in the United States and around the world.
USGS Landsat Since 1972, the joint NASA/ U.S. Geological Survey Landsat series of Earth Observation satellites have continuously acquired images of the Earth’s land surface, providing uninterrupted data to help land managers and policymakers make informed decisions about natural resources and the environment.
The NASA/USGS Landsat Program provides the longest continuous space-based record of Earth’s land in existence. Landsat data give us information essential for making informed decisions about Earth’s resources and environment.
Landsat International Cooperators Since inception, the Landsat program has been an important component of U.S. foreign policy and science and technology strategies. The program’s longstanding network of International Cooperators (ICs), which operate numerous International Ground Stations around the world, embodies the U.S.’s policy of peaceful use of outer space and the worldwide dissemination of civil space technology to improve societal decision-making from national governments to local citizens.
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