"In some of the world’s most inaccessible places, tiny satellites are watching—and listening—for signs of destruction."
"Fishing boats kept washing up in Japan with dead North Koreans on board. Dozens were documented every year, but they spiked in 2017, with more than 100 boats found on the northern coasts of Japan. No one could explain the appearance of these ghost ships. Why were there so many?
An answer arrived in 2020. Using a swarm of satellites orbiting Earth, a nonprofit organization called Global Fishing Watch in Washington, DC, found that China was fishing illegally in North Korean waters, “in contravention of Chinese and North Korean laws, as well as UN sanctions on North Korea,” says Paul Woods, the organization’s cofounder and chief innovation officer. As a result, North Korean fishermen were having to travel further afield, as far as Russia, something their small ships weren’t suited for. “They couldn’t get back,” says Woods. China, caught out, promptly halted its activities.
The alarming discovery was made possible by the DC-based firm Spire Global, which operates more than 100 small satellites in Earth orbit. These are designed to pick up the radio pings sent out by boats across the globe, which are primarily used by vessels to avoid each other on the seas. Listening out for them is also a useful way to track illegal maritime activity."
Advertisement 
