As Threats in Space Mount, USA Lags in Protecting Key Services...

Global positioning satellites serve as clocks in the sky, and their signals have become fundamental to the global economy - as essential for telecommunications, 911 services and financial exchanges as they are for drivers and lost pedestrians. Those services are increasingly vulnerable as space is rapidly militarized and satellite signals are attacked on Earth. One Chinese satellite has a robotic arm that could destroy or move other satellites. Because low-Earth-orbit satellites are smaller and more dispersed, they are less vulnerable than GPS satellites to an attack in space. In the American GPS system, for example, each satellite carries atomic clocks and transmits radio signals with information about its location and the precise time. Some critical civilian systems were designed with a flawed assumption that satellite signals would always be available, according to the U.S. Cybersecurity and Infrastructure Security Agency. Satellite signals are transmitted on a narrow radio band, which makes it difficult for one nation to jam another's satellite signals without shutting off its own services.