Anthony J. Pennings, PhD

WRITINGS ON DIGITAL STRATEGIES, ICT ECONOMICS, AND GLOBAL COMMUNICATIONS

The Landsat Legacy

Posted on | November 3, 2017 | No Comments

“It was the granddaddy of them all, as far as starting the trend of repetitive, calibrated observations of the Earth at a spatial resolution where one can detect man’s interaction with the environment.” Dr. Darrel Williams, Landsat 7 Project Scientist

The Landsat satellite program is the longest-running program for sensing, acquiring, and archiving of satellite-based images of Earth. Since the early 1970s, Landsat satellites have constantly circled the Earth, taking pictures and collecting “spectral information” and storing them for scientific and emergency management services. These images serve a wide variety of uses, from gauging global agricultural production to monitoring the risks of natural disasters by organizations like the UNISDR. Landsat-7 and Landsat-8 are the current workhorses providing remote sensing services.[1]

The Landsat legacy began in the midst of the “space race,” when William Pecora, the director of the U.S. Geological Survey (USGS), proposed the idea of using satellites to gather information about the Earth and its natural resources. It was 1965, and the U.S. was engaged in a highly charged Cold War with the Communist world and space was seen as a strategic arena. Extensive resources had been applied to gathering satellite imagery for espionage, reconnaissance and surveillance purposes. Some of the technology was also being shared with NASA. Pecora stated that the program was conceived… “largely as a direct result of the demonstrated utility of the Mercury and Gemini orbital photography to Earth resource studies.” A remote sensing satellite program to gather facts about the natural resources of our planet was beginning to make sense.

In 1966, the USGS and the Department of the Interior (DOI) began to work with each other to produce an Earth-observing satellite program. They faced a number of obstacles including budget problems due to the increasing costs of the war in Vietnam. But they persevered, and on July 23, 1972, the Earth Resources Technology Satellite (ERTS) was launched. It was soon called Landsat 1, the first of the series of satellites launched to observe and study the Earth’s landmasses. It carried a set of cameras built for remote sensing by the Radio Corporation of America (RCA).

The Return Beam Vidicon (RBV) system consisted of three independent cameras that sensed different spectral wavelengths. They could obtain visible and near-infrared (IR) photographic images of the earth. RBV data was processed to 70 millimeter (mm) black and white film rolls by NASA’s Goddard Space Flight Center and then analyzed and archived by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center.

The second device on Landsat-1 was the Multispectral Scanner (MSS), built by the Hughes Aircraft Company. The first five Landsats provided radiometric images of the Earth through the ability to distinguish very slight differences in energy. The MSS sensor responded to Earth-reflected sunlight in four spectral bands.

This video discusses remote sensing imagery, how it is created, and variations in resolution.

Landsat’s critical role became one of monitoring, analyzing, and managing the earth resources needed for sustainable human environments. Landsat uses a passive approach, measuring light and other energy reflected or emitted from the earth. Much of this light is scattered by the atmosphere, but techniques have been developed to dramatically improve image quality.

After 45 years of operation, Landsat now manages and provides the largest archive of remotely sensed – current and historical – land data in the world. A partnership between NASA and the U.S. Geological Survey (USGS), Landsat’s critical role has been monitoring, analyzing, and managing the earth resources needed for sustainable human environments. It manages and provides the largest archive of remotely sensed – current and historical – land data in the world.

Landsat uses a passive approach, measuring light and other energy reflected or emitted from the Earth. Much of this light is scattered by the atmosphere, but techniques have been developed for the Landsat space vehicles to dramatically improve image quality. The following video discusses the Landsat programs in some depth and how researchers can use their data.

Each day, Landsat-8 adds another 700 high-resolution images to the extraordinary database, giving researchers the capability to assess changes in Earth’s landscape over time. Landsat-9 will have even more sophisticated technologies when it is launched into space in 2020.

Recently, major disasters due to hurricanes in the southern US states and the Caribbean have been monitored by the Landsat satellites. The year 2017 will be noted for major disasters including Hurricane Maria in Puerto Rico, hurricane Irma in the Caribbean, and Hurricane Harvey and associated flooding in Texas.[2]

Notes

[1] Landsat 8 was launched in 2013 and images the entire Earth every 16 days. It is the eighth Landsat to be launched although Landsat 6 crashed into the Indian ocean during liftoff in October 1993.
[2] USGS has released a recent report on all 4 major hurricanes of 2017 that adversely affected the southern US.

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AnthonybwAnthony J. Pennings, PhD is Professor and Associate Chair of the Department of Technology and Society, State University of New York, Korea. Before joining SUNY, he taught at Hannam University in South Korea and from 2002-2012 was on the faculty of New York University. Previously, he taught at St. Edwards University in Austin, Texas, Marist College in New York, and Victoria University in New Zealand. He has also spent time as a Fellow at the East-West Center in Honolulu, Hawaii.

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    Professor and Associate Chair at State University of New York (SUNY) Korea. Recently taught at Hannam University in Daejeon, South Korea. Moved to Austin, Texas in August 2012 to join the Digital Media Management program at St. Edwards University. Spent the previous decade on the faculty at New York University teaching and researching information systems, media economics, and strategic communications.

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