A satellite researcher who previously located a long-lost NASA satellite has discovered that as many as 170 SpaceX-developed Starshield satellites have been sending their signal in the wrong direction. Operated by the US government’s National Reconnaissance Office (NRO), the satellites could interfere with ground station signals, potentially impacting the work of other governments, some television broadcast services, and backend telecoms systems.
It’s not clear if the emissions are a mistake or deliberate.
The researcher is Scott Tilley, an engineering technologist and amateur radio astronomer in British Columbia. He found that the satellites were emitting signals across Canada, the United States, and Mexico within the 2025–2110 MHz band. This band is primarily reserved for uplink communications with spacecraft in orbit. Satellites sending downstream signals in this frequency band may interfere with it.
Credit: Scott Tilley/Ars Technica
Ars Technica’s sources suggest that the NRO likely coordinated with SpaceX and telecom companies to ensure its satellites wouldn’t interfere with domestic signals. Still, it’s unclear whether such arrangements were made with other governments or international organizations. Either way, it needs investigating, Tilly said.
“The apparent downlink use of an uplink-allocated band, if confirmed by authorities, warrants prompt technical and regulatory review to assess interference risk and ensure compliance” with international regulations, he said in a report on the matter.
The reason for the signals certainly warrants further investigation. Although other commenters have suggested you’d only spot these signals if you went looking for them and were pointing a dish directly at the Starshield satellites, it’s still not clear what they’re for. Any illegitimate use of frequency spectrums raises the risks of inhibiting projects that aren’t in communication with one another.
“Cooperative disclosure—without compromising legitimate security interests—will be essential to balance national capability with the shared responsibility of preserving an orderly and predictable radio environment,” Tilly argues in his paper.
Although he concludes that he doesn’t know what the signals are for, he alludes that it could be a deliberate attempt to blanket the frequency band.
“While it is not suggested that the system was designed for that role, the combination of wideband data channels and persistent carrier tones in a globally distributed or even regionally operated network represents a practical foundation for such use, either by friendly forces in contested environments or by third parties seeking situational awareness,” the paper said.