homehome Home chatchat Notifications


How Declassified Cold War Satellite Images Are Helping Find Bombs and Mines Buried for Decades in Southeast Asia

Old spy satellites and new AI help unearth the hidden bombs of Southeast Asia.

Tudor Tarita
May 6, 2025 @ 3:06 pm

share Share

A man from Mines Advisory Group is carefully extracting unexploded ordnance from the ground
A man from Mines Advisory Group is carefully extracting unexploded ordnance from the ground. Credit: Mines Advisory Group/Bart Verweij

In the rice fields of Cambodia and the forested hills of Vietnam, dangers of the past lie dormant. Long after the last shots of war echoed across Southeast Asia, its unexploded aftermath still maims, kills, and cripples lives and livelihoods. But now, a remarkable alliance of history, technology, and human determination is bringing this invisible war into the light.

A Dangerous Inheritance

From the late 1960s to the end of the 1990s, Cambodia became a battleground for rival factions in a protracted civil war. As the fighting raged, an estimated ten million landmines and explosives were scattered across the country. Over half are believed to remain buried. Since the conflict ended in 1998, more than 20,000 people have died in Cambodia from mine-related incidents. Another 45,000 have been injured.

“There were over 50 accidents last year,” Tobias Hewitt, country director for Cambodia at the HALO Trust, a demining NGO, told Space.com. “The number is steadily decreasing, but it’s still a huge problem.”

An old satellite image from the Hexagon program showing where a road used to be in Cambodia. Credit: HALO/NRO.

In neighboring Vietnam, the toll is just as severe. The U.S. dropped millions of tons of bombs across the region during the Vietnam War—more than in World War II and Korea combined. Many failed to detonate, especially in fertile regions where the soft, wet soil cushioned their impact.

“You have farmers that are essentially in the most fertile areas who were the most afraid to farm because these are the most dangerous areas,” Erin Lin, a political scientist at Ohio State University who studies the environmental legacy of war, told Whyy.

Today, locals still farm those same lands, because they must. “If we don’t do it, then we don’t have anything … to get income, or anywhere to live,” said Hoàng Thi Mai Chi, a community assessment manager with the Mines Advisory Group in Vietnam. As a child, she witnessed the tragic aftermath of a bomb explosion that killed two young boys. She’s dedicated her life to ensuring it doesn’t happen again.

Revealing Mine Fields from the Sky

For decades, demining crews have worked slowly and carefully, sweeping fields with metal detectors. But pinpointing where to look has often felt like educated guesswork. That started to change in 2011, when the U.S. declassified nearly 30,000 images from its Cold War-era HEXAGON spy satellites.

“We were able to overlay those old images on regular Google Earth images and find old roads, for example,” said Hewitt. “That’s a huge help, because that’s where most mines would be put in the ground. We would not be able to know about them otherwise.”

Roads are important clues because retreating forces frequently laid mines to slow enemies. But many of these old military routes have since vanished beneath jungle or farmland. “If they don’t know that there used to be a road, they just assume it’s farmland and plough it,” Hewitt explained. “Unfortunately, accidents happen.”

The satellite images are helping HALO Trust prioritize high-risk zones. In the last few months alone, the group has mapped thousands of suspect sites in western Cambodia. Still, each location must be painstakingly verified in person. “We have to manually sync those images with our existing maps and then go over them inch by inch,” Hewitt said.

Meanwhile in Vietnam, data scientist Philipp Barthelme had a similar idea. During the pandemic, he began analyzing declassified CIA satellite photos for bomb craters. The U.S. military had carpet-bombed vast regions. Barthelme trained an AI model to recognize different crater types and predict where bombs may have landed—but not exploded.

“The … technical part of detecting the bomb craters is really the more straightforward part,” he said. “Then it’s about collaborating with some of these NGOs … to understand how that could be integrated in their operations.”

His work, now a PhD project at the University of Edinburgh, could speed up searches dramatically. But there are limits. Large bombs leave visible craters. Cluster munitions—smaller, scattered explosives—often do not.

Some new survey areas in Cambodia that have been outlined for future work and/or full land mine clearance, thanks to declassified imagery from U.S. spy satellites
Some new survey areas in Cambodia that have been outlined for future work and/or full land mine clearance, thanks to declassified imagery from U.S. spy satellites. Credit: HALO/Google Maps

The Machines Join In

Efforts to integrate modern AI into mine detection are also gaining traction. Martin Jebens and his colleagues at the International Committee of the Red Cross developed DeskAId, a machine learning tool that predicts mine locations using satellite imagery and historical data.

Already being tested in Cambodia, the system analyzes proximity to roads, buildings, and hospitals to detect patterns from previous conflicts. It boasts up to 92 percent accuracy. But its creators acknowledge that while machines can guide, only humans can confirm.

“There is massive, massive potential for efficiencies: time-saving, money-saving and, ultimately, hopefully, life-saving,” Andro Mathewson told New Scientist.

Still, progress is constrained by scale and funding. Cambodia has cleared about 3,200 square kilometers (1,200 square miles) of contaminated land—yet over 470 square kilometers (180 square miles) remain. In Vietnam, the extent of contamination is still unknown. Many bombed regions are mountainous and remote, requiring hours of travel just to reach. And during the second Trump administration, U.S. foreign aid for bomb removal paused for over a month—a jarring interruption for programs heavily reliant on U.S. support.

“There’s always a question of: Does America have a moral obligation to fund the clearance as it actually put the ordinance there in the first place?” said explosives consultant Seán Moorhouse. “Any reduction in funding would be disastrous for Vietnam.

Today, Hoàng Thi Mai Chi works with farming families, helping them live—and survive—among the remnants of a decades-old war. She now has children of her own.

“We never forget what happened in the past. Even my kids now … are curious about the war and what was going on. However, we have to move on,” she said. “We coordinate and work with different countries, not just America, to build Vietnam and to make peace happen in more countries in the world.”

But peace, as Southeast Asia’s farmers know all too well, is not just about the end of war. It’s about reclaiming the land, one square meter at a time, from a conflict that refuses to stay buried.

share Share

How dogs and cats are evolving to look alike and why it’s humans’ fault

Human fashion can be as powerful as millions of years of evolution – and it’s harming our pets.

Mathematicians Just Solved a 125-Year-Old Problem That Unites Three Major Theories of Physics

A new mathematical proof connects atoms to ocean waves and jet streams.

Nature Built a Nuclear Reactor 2 Billion Years Ago — Here’s How It Worked

Billions of years ago, this uranium went a bit crazy.

Archaeologists Discover 1,800-Year-Old Roman Cavalry Horse Cemetery in Germany

These horses served the Roman Empire and were buried with military precision.

What Your Emoji Use Really Says About You, According to Science

If you use a lot of emojis, you'll want to read this.

Your Brain Data May be Up For Sale and It's Totally Legal (For Now), Say U.S. Senators

Lawmakers warn brainwave data could expose mental health and be sold without consent.

6 Genetic Myths Still Taught in Schools (That Science Says Are Wrong)

Many traits we learn as 'genetic facts' are more folklore than fact.

This Indigenous Group Doesn’t Sing to Babies or Dance—and It’s Reshaping Anthropology

Cultural trauma and loss can silence even the most human of traditions.

This Chip Trains AI Using Only Light — And It’s a Game Changer

Forget electricity — this new AI chip from Penn learns using light.

Scientists Tracked Countless Outcomes of Spanking Children and Found Zero Benefits. On the Contrary, There Is Only Harm

Even in countries where it’s culturally acceptable, physical punishment leads to negative outcomes.