As a NASA science flight flew over the Greenland ice sheet this spring, a surprise appeared on special radar: a hidden Cold War city more than 100 feet (30 meters) beneath the ice.

In April 2024, a team of engineers and scientists flew on NASA’s Gulfstream III and tested NASA’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) mounted on the belly of the aircraft.

A photo of the Greenland ice sheet and a NASA UAVSAR image from Camp Century.

(NASA)

Unlike standard radar, which produces 2D images of the ice sheet, UAVSAR creates a more dimensional mapping, which is why the returned image showing the U.S. Cold War relic known as Camp Century was so clearly visible.

The map above from UAVSAR shows a clear layout of Camp Century compared to the 2D image below.

A 2D radar profile of the Greenland ice sheet, where Camp Century can be seen beneath the ice.

(NASA)

“We were looking for the ice bed and Camp Century popping out,” said Alex Gardner, a cryosphere scientist at NASA’s Jet Propulsion Laboratory. “We didn’t know what it was at first.”

Camp Century was a US military base built in 1959 in the Greenland ice sheet with a network of tunnels and infrastructure. According to NASA, it is known as the “City Under the Ice.”

According to the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES), the top-secret location doubled as a test site for the possible use of nuclear missiles from the Arctic during the Cold War.

On the left is a map of Camp Century. At right, a photo of the construction of a 100-foot-long arch extension to the main facility tunnel, taken in May 1960 at Camp Century.

The construction was a major challenge for engineers and teams in Greenland. According to the US Army Corps of Engineers post-build report, temperatures during construction ranged from 10 to 20 degrees below zero. Limited daylight and blowing snow also posed a challenge.

When the base was abandoned in 1967, years of ice and snow buried the nuclear-powered base more than 115 feet underground.

Camp Century was once believed to be buried in ice forever, but a study conducted by CIRES in 2016 concluded that a changing climate means Camp Century is no longer considered “preserved for eternity.” can. CIRES researchers found that melting and thinning of the ice sheet could expose any remaining biological, chemical and radioactive waste from Camp Century.

An aerial view over Camp Century from July 1960, showing open ends of power plant tunnels and an incomplete arch over a reactor tunnel, as well as PM-2A equipment on sleds as delivered to Century.

(US )

The study, conducted by CIRES, used ground-penetrating radar to estimate the amount of waste beneath the ice. The team found that the waste at Camp Century covers about 136 acres, about the size of 100 football fields, and contains an estimated 53,000 gallons of diesel fuel and 63,000 gallons of wastewater.

NASA says scientists continue to use conventional radar to confirm estimates of Camp Century’s depth and estimate when melting and thinning of the ice sheet could reveal the Cold War relic.

The incidental observation by NASA’s UAVSAR could be helpful in future mapping of the Greenland ice sheet and when Camp Century debris could become a problem.