“My guess is they were allowed to operate on a non-interference basis and if there is an interference issue, they’d have to go figure a way to resolve them,” he said.

Tilley told Ars that Article 4.4 allows for non-interference use domestically but “is not a blank check for continuous, global downlinks from a constellation.” In that case, “international coordination duties still apply,” he said.

Tilley pointed out that under the Convention on Registration of Objects Launched into Outer Space, states must report the general function of a space object. “Objects believed to be part of the Starshield constellation have been registered with UNOOSA [United Nations Office for Outer Space Affairs] under the broad description: ‘Spacecraft engaged in practical applications and uses of space technology such as weather or communications,’” his paper said.

Tilley told Ars that a vague description such as this “may satisfy the letter of filing requirements, but it contradicts the spirit” of international agreements. He contends that filings should at least state whether a satellite is for military purposes.

“The real risk is that we are no longer dealing with one or two satellites but with massive constellations that, by their very design, are global in scope,” he told Ars. “Unilateral use of space and spectrum affects every nation. As the examples of US and Chinese behavior illustrate, we are beginning from uncertain ground when it comes to large, militarily oriented mega-constellations, and, at the very least, this trend distorts the intent and spirit of international law.”

China’s constellation

Tilley said he has tracked China’s Guowang constellation and its use of “spectrum within the 1250–1300 MHz range, which is not allocated for space-to-Earth communications.” China, he said, “filed advance notice and coordination requests with the ITU for this spectrum but was not granted protection for its non-compliant use. As a result, later Chinese filings notifying and completing due diligence with the ITU omit this spectrum, yet the satellites are using it over other nations. This shows that the Chinese government consulted internationally and proceeded anyway, while the US government simply did not consult at all.”