‘A fair number of SpaceX’s gateways would cause unacceptable interference,’ Iridium tells the FCC, citing the company’s ongoing tests.
SpaceX’s effort to upgrade Starlink with gigabit speeds is facing resistance from rival satellite communications provider Iridium, which argues the proposed “gateway” stations risk creating radio interference.
On Monday, an attorney for Iridium sent a letter to the Federal Communications Commission, warning the interference problems have been appearing in the company’s own simulations examining the potential impact to Iridium’s own ground facilities.
“Although Iridium has not completed its assessment, it can tell from the results so far that the SpaceX gateways closest to Iridium’s gateways would produce interference that exceeds by a wide margin the maximum permissible levels. Put another way, a fair number of SpaceX’s gateways would cause unacceptable interference,” the letter says. In addition, Iridium is urging the FCC to block SpaceX from using the affected radio spectrum at 28 related gateway applications.
Gateway facilities on the ground are crucial to beaming data to orbiting satellites, which then relay the traffic to user devices. In SpaceX’s case, the company already has more than 100 gateway sites in the US, “comprising a total of 1.500+ antennas.” To upgrade the satellite internet service with gigabit speeds, SpaceX is not only preparing to launch next-generation V3 satellites, but is also preparing to build new gateway facilities capable of harnessing even more radio frequencies.
In April, SpaceX filed with the FCC to build a next-gen gateway station in Bastrop, Texas, requesting permission to use a wide-range of airwaves, including in the 19.4 to 19.6 GHz and 29.1 to 29.3 GHz bands. The company has since filed a growing number of applications to build similar sites across the US.
But in May, Iridium formally petitioned the FCC to block SpaceX from using the 19.4 to 19.6. and 29.1 to 29.3 GHz bands for the new gateway stations. That’s because Iridium uses the same radio spectrum as “feeder links” to supply data for the company’s mobile satellite services, which includes navigation, messaging and data.
Iridium told the Commission: “Section 25.203(k) of the Commission’s rules requires that SpaceX either coordinate those operations with Iridium or demonstrate that the operations will not cause unacceptable interference to Iridium. SpaceX has done neither, and its Applications are therefore facially deficient.”
SpaceX didn’t immediately respond to a request for comment. But in FCC filings, the company has been calling for the Commission to dismiss Iridium’s protests, saying its own simulations show no such interference will occur.
“SpaceX’s proposed earth station site in Bastrop, TX, is over 1.400 kilometers away from Iridium’s closest feeder link stations in Chandler and Tempe, Arizona. At this distance, geographical separation and atmospheric attenuation preclude any potential risk of unacceptable interference,” SpaceX’s satellite policy associate Matthew Turk told the Commission in June. “Commission rules do not require SpaceX to complete coordination with Iridium prior to applying, receiving a license, or operating feeder links from Bastrop, TX, so long as SpaceX demonstrates its ability to protect incumbent feeder links from unacceptable interference.”
In addition, the company says Iridium’s requests amount to placing “heightened restrictions on SpaceX’s operations that would delay the deployment of high-quality broadband services to consumers that need it most.”
However, Iridium has told the FCC that SpaceX’s interference analysis “rests on a faulty premise,” claiming it focuses on fixed satellite services, rather than mobile satellite services. “A denial will give the parties the necessary breathing room to continue their coordination discussions and to seek a resolution that satisfies SpaceX’s operational objectives without causing unacceptable interference,” Iridium wrote in Monday’s letter. “When parties are coordinating in good faith, asking the Commission to be the final arbiter should be the last resort, not the first.”