Stored fishing boats washing up in Japan with dead North Koreans on board. Dozens are documented every year, but they increased in 2017, with more than 100 ships found off the coast of northern Japan. No one could explain the appearance of these ghost ships. Why were there so many?
One answer came in 2020. Using a swarm of Earth-orbiting satellites, a nonprofit organization called Global Fishing Watch in Washington, DC, found that China was illegally fishing in North Korean waters , “in violation of Chinese and North Korean laws, as well as UN sanctions on North Korea,” says Paul Woods, the organization’s co-founder and chief innovation officer. As a result, North Korean fishermen had to travel further, to Russia, for which their small boats were not suitable. “They couldn’t come back,” says Woods. China, caught, quickly halted its activities.
The alarming discovery was made possible by the D.C.-based firm Spire Global, which operates more than 100 small satellites in Earth orbit. These are designed to pick up the radio pings sent by ships around the world, which are mainly used by ships to avoid each other at sea. Listening to them is also a useful way to track illegal maritime activity.
“The way they move when they’re fishing is different,” Woods says of the boats. “We can predict what type of fishing gear they’re using by their speed, direction and how they turn.” Of the 60,000 vessels emitting such pings, Woods says 5,000 have been caught doing illegal activities thanks to Spire, such as fishing during restricted hours or offloading hauls of protected fish to other vessels to avoid port controls.
Satellite constellations like Spire’s have seen a lot of growth in recent years, and new uses like this are becoming more common. Where satellites were once large, bulky machines costing tens of millions of dollars, technological advances mean that smaller, toaster-sized ones can now be launched at a fraction of the cost. Flying them together in groups or constellations to accomplish unique tasks has become an affordable prospect. “It is now economically viable to deploy many, many more satellites,” says Joel Spark, co-founder and CEO of Spire.
Before 2018, no constellation of more than 100 active satellites had ever been launched into Earth orbit, says Jonathan McDowell, a satellite expert at the Harvard-Smithsonian Center for Astrophysics in the US. Now there are three, with nearly 20 more constellations in the pipeline and about 200 more in development. It’s a “boom of constellations,” says McDowell.
The reasons for flying constellations are numerous. The most notorious is transmitting the Internet to remote locations, made famous by SpaceX’s Starlink mega-constellation. This vast swarm of 3,000 satellites accounts for nearly half of all in orbit, and will increase further to 12,000 or more. Others, like Amazon, have plans for large space internet constellations of their own. Many are concerned about launching so many satellites into orbit, significantly increasing the risk of collisions and producing dangerous space junk.