The Landsat Program

Objectives

• To describe the mission of the Landsat program
• To briefly describe the history of Landsat
• To describe the current Landsat 7 satellite and its capabilities

Mission

The Landsat program consists of a series of U.S. satellites designed to acquire high resolution remotely sensed images of the Earth's land surface and surrounding coastal regions. For more than 25 years, these satellites have 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 and national security.

Data from Landsat is used for monitoring population changes in and around metropolitan areas, monitoring global deforestation and fire damage, estimating soil moisture and snow water equivalence, and monitoring flood, storm, earthquake and volcanic eruption damage. Additional applications include studies of tropical deforestation, timber losses in the U.S. Pacific Northwest, soil moisture and snow water. The success of Landsat has established the United States as the world leader in land remote sensing and contributed significantly to our understanding of the Earth's environment.

With the 1999 launch of Landsat 7, the Landsat program's most recent addition, the program became part of a global research program known as NASA's Earth Science Enterprise, a long-term program that is studying changes in Earth's global environment. The goal of the Earth Science Enterprise is to provide people with a better understanding of natural environmental changes using a fleet of satellites, each designed to target a specific component of our environment. Landsat's primary role is to provide global, high-resolution measurements of land surface and surrounding coastal regions. All of the Earth Science Enterprise data will be distributed to researchers worldwide and will become an essential tool for making informed decisions about our environment.

History

In the mid to late 1960's NASA recognized the potential of using space technology to study the Earth's environment and initiated efforts to develop a program for remote sensing of earth resources from space. The objective of this program was to gather data about natural resources from earth observing satellites carrying remote sensing instruments. As a result the Earth Resources Technology Satellite (ERTS) was launched by NASA in July, 1972. The ERTS satellite, later re-named Landsat 1, marked the beginning of nearly three decades of the Landsat program, which continues to build a photographic record of our changing planet that is unmatched by any other research program in history.

Landsat 1 carried a television camera and an experimental sensor called the Multi-Spectral Scanner (MSS). This sensor was developed following several years of studies with airborne multispectral scanners, which provide scanned data of the Earth's surface in different portions of the electromagnetic spectrum. During its operational lifetime, Landsat 1 acquired over 300,000 images of the planet and established a rich set of data about global land surfaces that exceeded all expectations. The MSS proved so valuable and successful that it was included on the next four Landsat satellites, including Landsat 2, launched in January, 1975 and Landsat 3, launched in March, 1978. The historical record created by the early Landsat satellites forms the basis of comparison used to detect and measure change on our planet's surfaces.

Landsat 4, launched in July, 1982, carried a newly improved multispectral sensor called the Thematic Mapper, which marked the beginning of a second generation of remote sensing satellites. The Thematic Mapper added three new spectral bands and provided improved resolution of 30 meters (compared to the MSS resolution of 80 meters). Landsat 5, launched in March, 1984, also carried the Thematic Mapper and remains in limited operation today, continuing to contribute to Landsat's historical archive of images of the Earth.

In 1985, operation of the Landsat program was commercialized and the Earth Observation Satellite Company (EOSAT) assumed responsibility for operation of Landsat 4 and 5, managed the distribution of Landsat data, and built two new spacecraft (Landsat 6 and 7). Landsat 6 was launched in October, 1993 but failed to reach orbit and was lost. This satellite carried an improved version of the Thematic Mapper known as the Enhanced Thematic Mapper (ETM), which would have provided improved resolution and accuracy.

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