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Landsat completes 45 years: Tracing the journey

Lansat program - The longest, continuous Earth science observation program. Credits: USGS
Lansat program – The longest & continuous Earth science observation program. Credits: USGS

Landsat is a name congruous with earth observation. And why not, given that it is the longest-running enterprise for acquisition of satellite imagery of Earth! To date, the Landsat Program, which is jointly managed by NASA and the US Geological Survey (USGS), has archived over 7 million scenes and represents the world’s longest continuously acquired collection of space-based moderate-resolution land remote sensing data. Landsat data provides essential information to policymakers and corporate entities make informed decisions about our natural resources and environment. The program was initially called the Earth Resources Technology Satellites Program, which was used from 1966 to 1975.

On July 23, as the Landsat program completed 45 years of continuous observation of Earth from space, we look back in history to trace the timeline of significant details.

1966: Project EROS, a programed “aimed at gathering facts about the natural resources of the Earth from earth-observing satellites carrying sophisticated remote sensing observation instruments”, announced by Interior Secretary Stewart L. Udall in 1966. Secretary Udall named Dr. William T. Pecora, the Director of the US Geological Survey, named as the head of the program.

1969: The same year first moon landing took place, the Hughes Santa Barbara Research Center initiated, designed, and fabricated the first three multispectral scanners. The first prototype MSS was tested in 1970.

showing the greater Dallas
The very first image in the Landsat archive showing the greater Dallas area of Texas on July 25, 1972. The resolution is 60 meters per pixel in this false-color image, where shades of red indicate vegetated land and grays and whites are urban or rocky surfaces.

1972: The first Earth Resources Technology Satellite (ERTS) launched on July 23 by NASA. The satellite carried one of these multispectral scanners built by Hughes along with a camera built by the Radio Corporation of America known as the Return Beam Vidicon. Landsat 1 had a minimum design life of one year but operated nominally until January 1978 when a tape record malfunctioned and the spacecraft was taken out of service. Over the 78-odd months of its service, Landsat 1 acquired over 150,000 multispectral scanner scenes from around the world.

Landsat 2
The behemoth wideband video tape recorders that flew on the first three Landsats had 1,800 feet of tape and weighed in at 76-pounds each. This is a grainy photo of a WBVTR from a 1975 Landsat 2 post-launch evaluation document. — Courtesy NASA

1975: The second satellite in the series — a near-identically copy of the first — launched in January. It also carried a Return Beam Vidicon (RBV) and another multispectral scanner. Landsat 2 was terminated in February 25, 1982.

1975: Sometime during this time the program eventually rechristened Landsat.

1978: The third in the series — again a near-identical copy of the first two — launched March. However, in addition to the similar payloads consisting of a Return Beam Vidicon and a multispectral scanner, there was short-lived thermal band. Landsat 3 continued operations till March 1983.

1979: President Jimmy Carter transferred the operations of the Landsat program from NASA to National Oceanic and Atmospheric Administration (NOAA). The Presidential Directive 54 also recommended that NOAA develop a long-term operational system with four additional satellites beyond Landsat 3, and recommended transition to private sector operation of Landsat.

1982: Landsat 4 launched in July, carrying an updated multispectral scanner used on previous Landsat missions, as well as a thematic mapper. It continued to operate till December 1993.

1984: Landsat 5, a near-identical copy of Landsat 4, launched in March, carrying the same payload consisting of a multispectral scanner as well as a thematic mapper. Landsat 5 went onto become the longest Earth-observing satellite mission in history when it was shut down in January 2013.

International ground stations have been collecting Landsat data from the very beginning. starting with Canada in 1972. This animation shows active international ground stations and their acquisition circles over the lifetime of the Landsat program. Credits: USGS

1985: Earth Observation Satellite Company (EOSAT), a partnership of Hughes Aircraft and RCA, was selected by NOAA to operate the Landsat system with a 10-year contract. EOSAT operated Landsat 4 and Landsat 5, had exclusive rights to market Landsat data, and was to build Landsats 6 and 7.

1989: NOAA’s funding for the Landsat program was due to run out and it directed Landsats 4 and 5 to be shut down. Vice President Dan Quayle, who was heading the newly formed National Space Council, arranged emergency funding enabling the program to continue with the data archives intact.

1999-91: US Congress provided only half of the year’s funding to NOAA, requesting that agencies using Landsat data provide the funding for the other six months of the upcoming year.

1992: Various efforts made to procure funding for follow on Landsats and continued operations, but by the end of the year EOSAT ceased processing Landsat data.

1992: Congress passes the Land Remote Sensing Policy Act (Public Law 102-555), thus recognizing the value of the Landsat program. The Act instructed Landsat Program Management to build a government-owned Landsat 7 and assuring the continued availability of Landsat digital data and images, at the lowest possible cost, to traditional and new users of the data.

1993: Landsat 6 launch failed in October when it failed to reach orbit. The satellite was an upgraded version of its predecessors carrying the same multispectral scanner but also carrying an enhanced thematic mapper with an additional 15-meter resolution panchromatic band.

1999: Landsat 7 launched on April 15. The main component on the satellite was the Enhanced Thematic Mapper Plus (ETM+). It still has a 15-meter resolution panchromatic band, but also includes a full aperture calibration. Landsat 7 is operating with scan line corrector disabled since May 2003.

2001: EOSAT, now renamed Space Imaging, returned the operational responsibility for Landsat 4 and Landsat 5 back to the US Government. It also relinquished the commercial right to Landsat data, enabling the USGS to sell all Landsat 4 and Landsat 5 data in accordance with the USGS pricing policy.

2013: Landsat 8 launched. It was originally named Landsat Data Continuity Mission until May 30, 2013, when NASA operations were turned over to USGS. Landsat 8 has two sensors with its payload, the Operational Land Imager and the Thermal InfraRed Sensor (TIRS).

2020: Landsat 9 scheduled for launch. The Landsat 9 mission is a partnership between NASA and the USGS. It will be a rebuild of Landsat 8, but with a higher imaging capacity than past Landsats. With an aim to collect around 720 scenes per day, Landsat 9 will operate in a WRS-2 orbit with 98-min single orbital path.NASA will build, launch, perform the initial check-out and commissioning of the satellite; USGS will operate Landsat 9 and process, archive, and freely distribute the mission’s data.

WATCH THIS: Film illustrates how the Earth Resources Technology Satellite (ERTS) helped to meet the need for a worldwide survey of Earth resources in order to assist scientists and governments plan their use and conservation.” Produced for NASA by Audio Productions.