For Mihai Nita, not being able to see the forest for the trees is not just a colloquial language, but a professional disadvantage.
“When I go into the forest, I can only see 100 meters around me,” said Dr. Nita, forest engineer at the Transylvania University of Brasov in Romania.
Dr. Nita’s research interest – the history of Eastern European forests – depends on a wider and more distant perspective than the eyes can provide.
“You have to see what happened in the 50s or even a century ago,” said Dr. Nita. “We needed an eye in the sky.”
In order to map the history of a landscape, foresters like Dr. For a long time Nita had to rely on maps and traditional tree inventories, which could be riddled with inaccuracies. But now they have a bird’s eye view that is the result of an American espionage program of the 20th century: the Corona Project, which launched classified satellites in the 1960s and 1970s to research the secrets of the Soviet military. In doing so, these circling observers collected around 850,000 images that were classified by the mid-1990s.
Modern ecologists who record valuable or lost habitats have breathed a second life into the corona images. Together with modern computers, the space-based snapshots have helped archaeologists identify ancient sites, demonstrate how craters left by American bombs during the Vietnam War became fish ponds, and tell the tale of the transformation of Eastern European tree cover in World War II.
Though static, the panoramic photos contain recognizable imprints – penguin colonies in Antarctica, termite mounds in Africa, and cattle grazing trails in Central Asia – that reveal the dynamic life of the terrestrial inhabitants below. “It’s Google Earth in black and white,” said Catalina Munteanu, a biogeographer at Humboldt-Universität zu Berlin, who used corona images to show that marmots have returned to the same caves in decades of destructive agricultural practices in Kazakhstan.
Modern systems such as the Terra, Aqua, Copernicus and Landsat satellites provide environmental scientists with regularly updated images of the planet’s surface. However, the satellites have only been around for a few decades – four at most – and many offer less detailed resolution than the photos taken by Corona.
More importantly, the spy satellites allow scientists to extend the timeline of a landscape even earlier into the 20th century. This paradoxically helps us predict what’s next.
“If you double or triple the age of this data set,” said Chengquan Huang, geographer at the University of Maryland, “you can improve your modeling skills significantly in the future.”
For example, in 2019 a group of scientists used corona imagery, historical maps, and modern satellites to trace the fluctuating boundaries of Lake Phewa in Nepal over time. Then the researchers predicted what might come next, estimating that the shrinking lake could lose 80 percent of its water within the next 110 years. Loss on this scale would destroy the lake’s ability to provide water for hydropower generation, irrigation and tourism that hundreds of thousands of people in Nepal rely on.
“We can use images from the past to inform the future,” said C. Scott Watson, a geoscientist at the University of Leeds and co-author of the Phewa Lake study.
Images that kept the Cold War cold
At the beginning of the Cold War, the United States was struggling to obtain military information about the Soviet Union – a huge enemy that spans 11 time zones and one-sixth of the planet’s land surface.
The satellite reconnaissance provided a glimpse into the Soviet black box, said James David, a curator at the Smithsonian’s National Air and Space Museum in Washington. “Photo Intelligence tells you where the enemy’s forces are,” he said. “It can go a long way to tell you what equipment you have and how ready you are.”
An early response was Corona, approved by President Eisenhower in 1958. However, in order to photograph the enemy from space, US officials first had to perform technical feats: develop films that withstand space radiation and atmospheric pressure, and then retrieve, develop, and carefully analyze them.
The first dozen attempted launches of Corona satellites failed, according to the CIA. Some of the vehicles failed to make it into orbit or back, others experienced camera or film breakdowns.
Then, in August 1960, the first successful Corona flight made eight day passes over the Soviet Union. When the camera had consumed all of its 20 pounds of film, the satellite released its film return capsule from a height of 100 miles. The package hit the atmosphere, deployed a parachute, and was picked up in midair by an Air Force aircraft northwest of Hawaii. It was the first photograph ever recovered from orbit.
“They had no idea if these systems would work,” said Compton Tucker, a senior earth scientist at NASA’s Goddard Space Flight Center. “It’s really very awesome.”
Over time, the quality of Corona cameras and films has improved. With an archive of nearly a million images, the program discovered Soviet missile sites, warships, naval bases, and other military targets. “They counted every missile in the Soviet Union,” said Volker Radeloff, an ecologist at the University of Wisconsin – Madison, whose laboratory used the images in his studies. “These pictures kept the Cold War cold.”
After 145 missions and 120 usable film canisters returned, the multi-billion dollar Corona program was shut down in 1972 in favor of satellites that could send their images back to earth in digital format.
When the spy program’s archive images were released in 1995, some appeared on the front page of The Times.
Government officials were motivated to post the images partly because of their expected value to environmental scientists.
“These kinds of photos,” said Vice President Gore at the time, “make today’s event so exciting for those studying the process of change on our planet.”
Since then, the program has remained relatively unknown to the public. “It’s the best military, taxpayer-funded achievement that nobody knows about,” said Jason Ur, a Harvard University archaeologist who regularly relies on corona imagery for his research.
One reason for their relative obscurity is that scientists trying to use the images had to overcome a variety of obstacles. For example, while the images were being released, it cost researchers $ 30 to digitize a single image. Dr. Radeloff said there was “a lot of data” but most of the images were “still rolled in film and not yet scanned”.
It took until recently for the software to be sophisticated enough to correct, orient and analyze the often distorted panoramic satellite images.
In 2015, Dr. Nita with the development of a method for processing corona images, which was inspired by software that corrects blurred drone material. “Computer programming wasn’t high enough before,” he said.
With this and other technological advances, research on corona data has increased. In the past two years alone, scientists have studied the images to track the movement of rock glaciers in Central Asia, changes in the coastline in Saudi Arabia, wadi trees in the deserts of eastern Egypt, and ice loss in Peru.
“Like a time machine” for the surface of the earth
Once struggled, Corona’s spy photos can reveal the history of a landscape beyond today’s era of widespread satellite imaging.
Corona’s snapshots from the 1960s often captured habitats before people developed wildly flooded, paved, plowed or wild spaces in new cities, hydroelectric plants, farmland or industrial areas. The images even challenged our assumptions about pristine ecosystems – and showed more than once that suspected old growth forests are actually younger than 70 years.
“In many cases, they lead us to landscapes that have disappeared and no longer exist,” said Dr. Ur. “Corona is like a time machine for us.”
In 2013, biologist Kevin Leempoel set out to understand the historical boundaries of the mangroves in the Zhanjiang Mangrove National Nature Reserve in southern China. The record was incomplete before the 1980s when global satellites began regularly documenting the surface of the planet from space. “There was this big gap – we really didn’t have another point in time,” said Dr. Leempoel, now at the UK’s Royal Botanic Gardens at Kew.
Dr. Leempoel examined black and white corona images and hand-marked the outlines of the forest. In 2013, he showed that mangrove cover fell by more than a third from 1967 to 2009 due to human activity. Without this kind of finding, it wouldn’t have been possible to see the historical photos, he said.
“In ecology we all face the same problem: at best we have good data in the 80s or 90s,” said Dr. Leempoel. “The difference between now and then is not great. But compared to a century ago, the difference is huge. “
Nevertheless, corona data remains relatively untapped by scientists. According to Dr. Radeloff, only 5 percent – around 90,000 images out of a total of 1.8 million – of the country’s steadily growing backlog of approved spy satellite photography have been scanned. “It hasn’t been used that often. We’re just outside the door, ”he said.
In the face of climate change and other global ecosystem transformations, it has never been more important to record and compose long-term environmental schedules, said Dr. Muntenau: “Everything we do leaves a footprint. These effects could only show up decades later. “