Landsat 5 images: the Aral Sea, once the fourth largest lake in the world, continues to shrink and is now 10 percent of its original size. The UN recently called the drying up of the Aral Sea one of the planet’s most shocking disasters. Picture: USGS
AFTER 29 years orbiting the planet, taking 2.5 million images, the longest operating satellite mission in history is being retired by the US Geological Survey.
Landsat images: three decades of change in the birdsfoot delta of the Mississippi River (top) and deforestation in Bolivia (bottom). Picture: USGS
Late last year the USGS announced that Landsat 5 will be decommissioned over the coming months, bringing to a close the longest-operating Earth observing satellite mission in history.
Landsat images: the area around the Chernobyl nuclear power plant in 1975 – before the construction of the cooling pond – 1986 and 2011 (top). In April 1986, the reactor had a massive accident and was destroyed. Lake Chad (bottom), once the sixth largest lake in the world, but now a twentieth of its former size after persistant drought. Pictures: USGS
By any measure, the Landsat 5 mission has been an extraordinary success, providing unprecedented contributions to the global record of land change. The USGS has brought the aging satellite back from the brink of failure on several occasions, but the recent failure of a gyroscope has left no option but to end the mission.
Landsat images: the fluctuations of Utah’s Great Salt Lake over 30 years (top), the explosive growth of Dallas-Fort Worth (bottom). Pictures: USGS
Now in its 29th year of orbiting the planet, Landsat 5 has long outlived its original three-year design life.
Developed by NASA and launched in 1984, Landsat 5 has orbited the planet over 150,000 times while transmitting over 2.5 million images of land surface conditions around the world.
Landsat 5 images: the Mergui Archipelago in the Andaman Sea consists of more than 800 islands. This natural-color image of the centre portion of the archipelago was captured by Landsat 5 in 2004. Photo: USGS
“This is the end of an era for a remarkable satellite, and the fact that it flew for almost three decades is a testament to the NASA engineers and the USGS team who launched it and kept it flying well beyond its expected lifetime,” said Anne Castle, Department of the Interior Assistant Secretary for Water and Science.
Landsat 5 images: much of Oman is desert, but the Arabian Sea coast in the Dhofar region represents a startling difference in climate. This coastal region catches the monsoon rains, or khareef, during the summer months. Drenching rains fall primarily on the mountainous ridge that separates the lush, fertile areas along the coast from the arid interior, recharging streams, waterfalls and springs that provide plentiful water supplies in the fertile lowlands for the remainder of the year. Photo: USGS
“Any major event since 1984 that left a mark on this Earth larger than a football field was likely recorded by Landsat 5, whether it was a hurricane, a tsunami, a wildfire, deforestation, or an oil spill,” said USGS Director Marcia McNutt.
Landsat 5 images: southern Africa’s Okavango River spreads across the pale, parched landscape of northern Botswana to become the lush Okavango Delta. The delta forms where the river empties into a basin in the Kalahari Desert, creating a maze of lagoons, channels and islands where vegetation flourishes, even in the dry season, and wildlife abounds. Photo: USGS
For more than a quarter of a century, Landsat 5 has observed our changing planet. It has recorded the impact of natural hazards, climate variability and change, land use practices, development and urbanisation, ecosystem evolution, increasing demand for water and energy resources, and changing agricultural demands worldwide.
Landsat images: the Aral Sea, once the fourth largest lake in the world, continues to shrink and is now 10 percent of its original size. The UN recently called the drying up of the Aral Sea one of the planet’s most shocking disasters. Picture: USGS
Vital observations of the Mount Saint Helens eruption, Antarctica, the Kuwaiti oil fires, the Chernobyl disaster, rainforest depletion, major wildfires and floods, urban growth, global crop production, and ice shelf expansion and retreat have helped increase our understanding and awareness of the impact of humans on the land.
Simon Crerar is News Limited’s Visual Story Editor, follow him at twitter.com/simoncrerar
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