(Credit: SpaceX's Starlink)
SpaceX is trying to dispel worries that its cellular Starlink service threatens to interfere with other satellite and ground-based services.
On Wednesday, the company sent a 16-page document to the Federal Communications Commission, explaining why the cellular Starlink service will benefit US consumers and not pose a radio signal hazard.
SpaceX filed the document after the FCC called on the company to provide more details and address the interference concerns. Specifically, the Commission asked if SpaceX can shut down the satellite transmissions in the event interference occurs.
In response, SpaceX tells the FCC: “In the unforeseen and unlikely case that harmful interference occurs, SpaceX is capable of ceasing transmissions from the satellite.” The company adds that each “active satellite transmission chain” can be individually turned off upon receiving commands from SpaceX’s ground control.
“SpaceX’s direct-to-cell network and topology software can re-plan the network in near real-time, allowing it to quickly cease operations by all satellites and over any number of geographic areas,” the company says.
(Credit: SpaceX)The cellular Starlink system will essentially turn the company’s satellites into orbiting cell towers, which can then beam data to unmodified smartphones on the ground. SpaceX’s first partner on the system is T-Mobile, which has secured radio spectrum over the 1.91 to 1.995GHz bands to transmit the cellular data.
To prevent interference, the company developed software that’s both smart and fast enough to fine-tune the satellite radio transmissions. “SpaceX will leverage efficient beam-planning software to ensure that its PCS G Block (radio signal) operations do not cause in-band or cross-border interference, consistent with T-Mobile’s license obligations,” the company says in its filing.
SpaceX is aiming to start launching satellites to support the cellular Starlink service as soon as possible, if the company can receive regulatory clearance from the FCC. The resulting network is poised to be vast, involving up to 7,500 Starlink satellites. But the company has encountered resistance from other cellular and satellite providers, including AT&T, Dish Network, and Apple’s satellite partner Globalstar, which have also raised the interference concerns with the FCC.
SpaceX is also facing opposition from Omnispace, a satellite communications provider, which has told the Commission that it’s “impossible” for the cellular Starlink service to operate without causing radio disruptions. “Omnispace believes SpaceX’s interference-free operation is unachievable in the real world,” the company said in October.
SpaceX disagrees. The company’s FCC filing includes a detailed interference analysis that tries to refute the allegations. The same analysis includes maps and data that argue SpaceX can “dynamically” adjust the Starlink radio signals to accommodate other satellite providers.
(SpaceX)“In all cases, SpaceX’s analysis demonstrates that SpaceX can maintain an interference level below Omnispace’s claimed harmful interference threshold at all times, even under the latest figures in Omnispace’s shape-shifting analysis,” the company said. The same analysis adds that the cellular Starlink is also designed to prevent interference with ground-based services.
SpaceX is now asking the FCC to "expeditiously grant" its application to operate the cellular Starlink service, which is aiming to start serving T-Mobile customers as soon as next year. The system will first offer satellite-based text messaging before expanding to voice and data in 2025.