NASA CELEBRATES
THE 25TH ANNIVERSARY OF LANDSAT

Remarks for the Congressional Record

July 23, 1997 marks the 25th anniversary of the launch of the first of the Landsat satellites that have continuously supplied the world with global land surface images since 1972.

When NASA's Administrator, Dr. James Fletcher, stated, in 1975, that if he had one space age development to save the world, it would be Landsat and its successor satellites, he was right. With a 25-year record of unique and scientifically important accomplishments, Landsat has indeed 'saved the world' -- capturing in images a photographic record spanning a quarter century of change upon the planet.

The data from the Landsat spacecraft constitute the longest record of the Earth's continental surfaces as seen from space. It is a record unmatched in quality, detail, coverage, and value.

Landsat's 25-year collection of land images serves hundreds of users annually who observe and study the Earth, who manage and utilize its natural resources, and who monitor the changes brought on by natural processes and man's activities. The images provide information meeting the broad and diverse needs of business, science, education, government, and national security.

The instruments on the Landsat satellites have recorded millions of images. These images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and other applications.

These data have been used to monitor timber losses in the U.S. Pacific Northwest, estimate soil moisture and snow water equivalence, and measure forest cover at the state level. In addition, Landsat spacecraft have been used to monitor strip mining reclamation, population changes in and around metropolitan areas and measure water quality in lakes. Landsat images have even been used by law firms to gather legal evidence and by the fast food restaurants to estimate community growth sufficient to warrant a franchise.

It is a fitting tribute to the early pioneers of Landsat and to all of those who have looked at the Earth through its lens, that the legacy will continue with the 1998 launches of the Landsat-7 satellite and its smaller, faster next generation counterpart, the Earth Observer-1 (EO-1) mission. With Landsat-7, scientists will gather remotely sensed images of the land surface and surrounding coastal regions for global change research, regional environmental change studies, national security uses and many other civil and commercial purposes. With the EO-1 single instrument mission, scientists will demonstrate new detector technology expected to result in significantly lower instrument costs for follow-on Landsat missions. All is in readiness to kick off the next quarter century of our mission to understand our planet and to 'save the world' -- NASA's Mission to Planet Earth.

A Brief History

The first Landsat, originally called ERTS for Earth Resources Technology Satellite, was developed and launched by NASA on July 23, 1972, on a Delta Rocket from Vandenberg, Air Force Base (VAFB), Calif. The satellite carried a television camera and an experimental sensor called the Multi-Spectral Scanner. The utility of the synoptic, digital, Multi-Spectral Scanner images was recognized rapidly and proved so valuable that a version of the sensor was flown on each of the following four Landsat satellites (NASA changed the name of ERTS to Landsat 1 in 1975). By the time Landsat 1 was retired in 1978, its Multi-Spectral Scanner had acquired over 300,000 images providing repeated coverage of the global land surfaces. The quality and impact of the resulting information exceeded all expectations.

Landsat 1 was followed by Landsat 2, launched on Jan. 22, 1975, and Landsat 3, launched March 5, 1978. Their Multi-Spectral Scanners built up the historical record of continental surface condition and change while continuing to provide valuable information on the current state of the land.

Landsat 4 carried a new sensor, the Thematic Mapper, inaugurating a second generation of remote sensing satellites when launched July 16, 1982. The Thematic Mapper was a significant improvement over the initial sensor, providing greater resolution in the visible and near-infrared regions (30 meters versus 80 meters) and three additional spectral bands. A second Thematic Mapper was launched aboard Landsat 5 on March 1, 1984. Landsat 5 remains in operation today, managed by a commercial firm, Space Imaging EOSAT, eight years beyond its design lifetime.

Landsat-6, managed by the Earth Observing Satellite Corporation (EOSAT), was launched from Vandenberg aboard a Titan II rocket, but the spacecraft failed to reach orbit after launch in October 1993.

The Landsat Mission is a central pillar of our national remote sensing capability. Landsat has:

For more than 25 years, the Landsat mission has provided detailed observations about the surface of our planet. Agricultural evaluations, forest management inventories, geological surveys, water resource estimates, coastal zone appraisals, and a host of other applications have been performed with Landsat data to meet the needs of business, government, science and education.

Continuation of these capabilities is required by a large and diverse constituency who depend upon the information afforded by the satellite system for a better picture of the planet on which we live. Landsat 7, with an Enhanced Thematic Mapper-Plus sensor, will offer the unique capability to seasonally monitor important small-scale processes on a global scale, such as the inter- and intra-annual cycles of vegetation growth; deforestation; agricultural land use; erosion and other forms of land degradation; snow accumulation and melt and the associated fresh-water reservoir replenishment; and urbanization

NASA is responsible for the development and launch of the Landsat 7 satellite and the development of the ground system. The Landsat Project at Goddard Space Flight Center manages these responsibilities with Hughes Santa Barbara Remote Sensing building the sensor and Lockheed Martin Missiles and Space developing the spacecraft. NOAA is responsible for operation and maintenance of the satellite and the ground system for the life of the satellite. The USGS, on behalf of NOAA, will capture, process, and distribute the data and is responsible for maintaining an archive of Landsat data.

The continuation of Landsat work is an integral component of the U.S. Global Change Research Program. Landsat 7 is part of a global research program known as NASA's Mission to Planet Earth, a long-term program that is studying changes in Earth's global environment. The goal of Mission to Planet Earth is to provide people a better understanding of natural environmental changes. Mission to Planet Earth data are essential to people making informed decisions about their environment. Landsat 7 will continue to provide critical information to those who characterize, monitor, manage, explore, and observe the land surfaces of the Earth over time.


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