"It's not often that a scientific discipline gains a 23-satellite constellation overnight," reports Science magazine, describing 16 years worth of radiation measurements from GPS satellites finally released by Los Alamos National Lab. "Although billions of people globally use data from GPS satellites, they remain U.S. military assets." Scientists have long sought the data generated by sensors used to monitor the status of the satellites, which operate in the heavy radiation of medium-Earth orbit and can be vulnerable to solar storms. But few have been allowed to tap this resource... That attitude changed in October 2016, when the outgoing Obama administration issued an executive order aimed at preparing the country for extreme space weather. Such bursts in charged particles, originating in a solar flare or coronal mass ejection, could disable the electrical power grid or divert flights away from the Arctic, where radiation exposure is heightened. The GPS data, which dates from December 2000, fill a hole in studies of space weather, the complex interplay of Earth's magnetic field with bombarding radiation from cosmic rays and the sun.