SpaceX may be violating international telecommunication standards by allowing its Starshield satellites to transmit to Earth on frequencies it’s not supposed to use, NPR reports. Starshield is a classified version of SpaceX’s Starlink satellite network offered on contract to government agencies “to support national security efforts,” according to the company’s website.

The report is based on findings from amateur satellite tracker Scott Tilley, who observed what appeared to be Starshield satellites broadcasting on frequencies normally dedicated to “uplink” transmissions from the Earth to satellites in orbit. Using the frequencies that way violates standards set by the International Telecommunication Union, a United Nations agency dedicated to coordinating the use of radio spectrum across the world.

Standards around which frequencies are used for uplink and downlink broadcasts to satellites were created to avoid interference, among other technical issues. “Nearby satellites could receive radio-frequency interference and could perhaps not respond properly to commands — or ignore commands — from Earth,” Tilley told NPR. It’s not clear yet whether SpaceX ignoring these rules is causing any issues with satellite communication, but should problems arise, there’s now a possible cause.

SpaceX’s first major Starshield project was a $70 million contract with US Space Force in 2023. More recently in 2024, there were reports that SpaceX’s Starshield division had been tasked with building out a network of spy satellites to gather imagery of Earth for the Department of Defense’s National Reconnaissance Office.