Landsat Celebrates 40 Years And Counting
July 24, 2012

Landsat Celebrates 40 Years And Counting

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Lee Rannals for - Your Universe Online

Monday marked the 40th anniversary of the Landsat program, the world's longest-running Earth-observing satellite program.

The first Landsat satellite was launched July 23, 1972 from Vandenberg Air Force Base in California.

Landsat has helped provide global coverage that shows large-scale human activities like building cities and farming. The program has been sustained by the U.S. to help provide direct societal benefits across a range of areas, including human and environmental health, energy and water management, urban planning, and disaster recovery and agriculture.

The Landsat pictures contain a variety of layers of data collected at different points along the visible and invisible light spectrum. A single image taken by the satellite 400 miles above Earth can accurately show the condition of hundreds of thousands of acres of grassland, agricultural crops or forests.

"Landsat has given us a critical perspective on our planet over the long term and will continue to help us understand the big picture of Earth and its changes from space," NASA Administrator Charles Bolden said in a statement. "With this view we are better prepared to take action on the ground and be better stewards of our home."

For the past 40 years, NASA's Landsat has kept an eye on Arizona's capital of Phoenix and neighboring towns in Maricopa County, revealing how the population has boomed over the last few decades.

When the first Landsat satellite launched, Maricopa County had grown to rank about 24th among U.S. counties nationally for population.

NASA has combined the images over the years, showing the transition of an area that use to boast 960,000 people, but has expanded to host 3,817,000.

Arizona was the second leading state for growth between 2000 and 2005, and most of the growth centered in Maricopa County.

Also over the years, Maricopa County increased from about 50,000 dairy cows, to more than 95,000, and irrigated land used for hay production stayed nearly constant at around 80,000 acres.

Land towards the middle of the map had clearly been developed at the beginning of Landsat's eye in the sky, but in 2011, Landsat images show how much the area has boomed over the years.

Water has changed over the years for the residents living around the area in the desert climate as well.

"During its earlier history, metropolitan Phoenix had used mostly local and nearby water sources, such as from the Salt River Valley and the mountainous Roosevelt Reservoir located north of the urbanized area," according to a NASA statement.

"In 1985, water from the Colorado River on the California-Arizona border began being pumped east as part of the Central Arizona Project (CAP), bringing additional resources both to Maricopa County and to the Tucson area."

NASA and the U.S. Geological Survey (USGS) launched six of the seven Landsat satellites, helping to create an archive of Earth observations for a record of human and natural land changes.

"Over four decades, data from the Landsat series of satellites have become a vital reference worldwide for advancing our understanding of the science of the land," Interior Department Secretary Ken Salazar said. "The 40-year Landsat archive forms an indelible and objective register of America's natural heritage and thus it has become part of this department's legacy to the American people."

NASA is preparing to launch the next Landsat satellite in February 2013 from Vandenberg. The Landsat Data Continuity Mission (LDCM) will be the most technologically advanced satellite in the Landsat series, bringing new advances in detector and sensor technologies.

"The first 40 years of the Landsat program have delivered the most consistent and reliable record of Earth's changing landscape," Michael Freilich, director of NASA's Earth Science Division in the Science Mission Directorate in Washington, said. "We look forward to continuing this tradition of excellence with the even greater capacity and enhanced technologies of LDCM."