China's Disappeared Uyghurs: What Satellite Images Reveal

Australian researchers had already mapped 380 suspected detention facilities scattered across Xinjiang, based on media reports, government documents, and their own review of satellite data. RAND’s team started there and then focused in on how the nighttime lighting at those locations changed over time, an indication of activity there. They saw the same pattern, again and again, starting in earnest in 2016: the glaring lights of construction work, followed by the steady glow of a new prison or detention center.

In fact, lighting kept increasing at nearly half of the facilities through at least mid-2020, an indication that they were not just active, but growing. At most other facilities, lighting levels stayed steady, or declined some, but never dimmed to where they had been before. That suggested to the researchers that those facilities were still operating, but possibly at reduced capacity.

The facilities that slowed down seemed to be mostly lower-security re-education sites. Those that grew looked more like prisons, with high walls spiked with barbed wire. That may indicate that China’s approach shifted in 2019 and 2020, from the short-term detention and re-education of Uyghur people to long-term incarceration.

Only 51 of the facilities showed the kind of significant lighting decline that could indicate a closure. But when researchers looked at satellite photos of those sites, they found evidence that most were still active. There were cars in the parking lots, people standing outside, walkways plowed of snow. Despite Chinese assurances that the camps had closed, the researchers concluded that only 11 of them—3 percent of the total they examined—showed any real signs of closure by mid-2020.

“The data is so granular that you can see, down to a city block, how bright the lights are, and how that changes, every month,” said Sean Mann, a policy analyst at RAND who specializes in data science. “Even in urban areas, we could identify these lighting signatures that showed us where they were establishing camps, where they were expanding them, and when they really decommissioned them.”

A Sustained Campaign
Journalists had reported seeing boarding schools in Xinjiang that appeared to house children whose parents had been taken away. The researchers began scrolling through satellite images to find these facilities. They identified nearly 100 in three towns alone—“postage stamp” buildings, often two or three stories tall, many with high walls and a single controlled point of entry. Some had decorative towers, some had colorful circles on the ground, but they all had a telltale play structure outside. Most of the schools appeared within a matter of months, just as the detention camps were lighting up.

The researchers also saw evidence of destroyed Uyghur cemeteries. China had acknowledged that it demolished some grave sites to make way for roads, parks, and high-rise buildings. The researchers did indeed find factories, farms, buildings, and green space on some of the old cemeteries. But nearly a third seemed to have been razed for no apparent reason.

RAND published its findings in a series of reports in the NGA’s public online journal, Tearline. Taken together, they provide new and visual evidence of the furious pace with which China carried out its detention campaign against the Uyghurs and other ethnic minority groups in Xinjiang. The satellite data “allowed us to capture and really understand the extent to which the broader detention network just kind of turned on overnight,” said Eric Robinson, a research programmer and analyst at RAND.

The researchers hope to continue piecing together a bird’s-eye view of what’s happening in Xinjiang. In particular, they want to take a closer look at allegations of forced labor in local factories, some of which supply major global brands. Their lighting data showed that camps administered by the state-owned Xinjiang Production and Construction Corps grew especially quickly.

Their work is a continuation of some of RAND’s earliest research. During the Cold War, RAND helped pioneer satellite technology as the United States raced to see behind the Iron Curtain. The first report it ever published, in fact, proposed a “preliminary design of an experimental world-circling spaceship,” a decade before the launch of Sputnik. Such an “observation aircraft,” the researchers wrote in 1946, would provide an unobstructed view across the “whole surface of the world.”

Doug Irvin is a communication analyst at RAND.This articleis published courtesy of RAND.