Will the United Nations’ International Telecommunications Union (ITU) ultimately relax the regulatory requirements governing Equivalent Power Flux-Density (EPFD) limits, which have long protected satellites in geostationary orbit from interference from non-geostationary satellite orbit (NGSO) systems?
That’s the question many satellite stakeholders, including those serving the aviation market, are asking now that the ITU has confirmed the next Radiocommunication Assembly (RA-27) and World Radiocommunication Conference (WRC-27) will take place in Shanghai, China, from 11 October to 12 November 2027.
Held every four years, the World Radiocommunication Conference reviews and revises the ITU Radio Regulations, the international treaty governing the use of the radio frequency spectrum and associated satellite orbits.
“During the four-week conference, ITU Member States will consider the results of technical studies and adopt decisions that shape the future use of spectrum for a wide range of radiocommunication services and applications, including mobile, satellite, radiolocation, radio astronomy, and space research services that support lunar communications,” ITU says.
As readers are well aware, the ITU does indeed have the power to shape the future of spectrum, and as such, the power to shape the future of many business propositions.
Pertinent to EPFD limits, there is, at present, a “GSO Protective” ITU Regulation (Article 22) which restricts mainbeam and even sidelobe emissions from NGSO terminals such that they do not individually nor in aggregate exceed specific Power Flux Density (PFD) levels as “seen” by geosynchronous orbit (GSO) satellites.
Depending on the user-terminal type (depending on size/beamwidth) the GSO Exclusion Zone extends anywhere +/- 12.5 and +/- 18 degrees on both sides of the “arc” of the GSO satellite plane (Clarke Belt). In the Ku-band, GSO satellites are currently designated “Primary” and must be protected from co-frequency NGSO users. Similarly, GSO protection rules apply for Ka-band NGSO satellites as well.
These are the EPFD requirements/restrictions for which SpaceX Starlink and others are seeking relaxation, firstly from the US Federal Communications Commission and eventually the ITU.
In its filing last year with the FCC, SpaceX argued that EPFD limits can require NGSO systems to implement large “avoidance angles” away from the arc of GSO satellites around the equator to prevent in-line interference events with GSO satellites, restricting the use of any satellite that appears within the GSO satellite avoidance angle with respect to a ground location. (pdf)
One could argue, as SES did in a 2023 blog post, that the vast number of NGSO satellite launches each year “is evidence that the current EPFD limits have not prevented or limited NGSO operators from deploying new satellite technologies and services, nor stifled innovation.”
And in aviation, specifically, SpaceX has secured a vast number of airline wins — recently adding IAG Group, Emirates and flydubai to a list that already includes Air France, Alaska Airlines, Qatar Airways, SAS, United Airlines, Virgin Atlantic and more — despite current EPFD limits.
Even so, in a notice of proposed rulemaking (NPRM) adopted on 28 April 2025, and published by the Federal Register on 13 June, the FCC said it is initiating a review of the “decades-old” spectrum sharing regime between GSO and NGSO systems operating in the 10.7-12.7, 17.3-18.6, and 19.7-20.2 GHz bands in which EPFD limits apply.
The ITU is also expected to address the issue, with an agenda item presented at WRC-2027 in Shanghai for possible action or relaxation four years later at WRC-2031. Unless and until EPFD limits are relaxed, all user terminals are required to show compliance to Article 22.
Making the case for why Article 22 EPFD limits should be revised by the ITU, SpaceX’s ITU lead for spectrum and regulatory affairs, Udrivolf Pica, said in a 2023 post on LinkedIn that: “The existing provisions, which were adopted a quarter century ago in 1997 and 2000, are spectrally inefficient and unnecessarily constrain non-GSO systems. Moreover, these limits were developed without considering long-term GSO protection criteria, thus overestimating GSO protection, with the clear result that critical spectrum lays underutilized.”
Pica argued that: “Real and operational systems like Starlink are being impacted already today, while systems that are being deployed will be constrained as soon as they commence operations.”
The stakes are clearly high. But what does Starlink’s adherence to avoidance angles away from the Clarke Belt mean for the airline passenger experience? Does it lead to a noticeably degraded Starlink connection when aircraft are flying across or near the equator?
Some satellite industry executives, who spoke to RGN on condition on anonymity, claim passengers can expect meaningful degradation for roughly 1,200 miles, as capacity around the equator, ‘if you’re flying either east/west or north/south, is massively degraded’. Others suggest it is less of an issue as laser links are increasingly in play.
SpaceX could not be immediately reached for comment so we posed a question to Grok, the AI company owned by Elon Musk.
Does Starlink inflight connectivity intentionally provide lower performance near the equator to comply with GSO protection under ITU’s Article 22, and what type of passenger experience can be expected?
Pulling from 44 sources, Grok provided an impressively exhaustive answer, suggesting that passengers can “expect seamless browsing, email, and social media, with reliable SD/HD video (e.g., Netflix at 1080p). However, heavy use like multi-device 4K streaming or large downloads may stutter for 10–20 minutes during peak equatorial transit.”
Appreciating that AI doesn’t have all the answers, and Grok isn’t always correct… Grok notably stated that while capacity at mid-Latitudes (including Europe, North America) can ‘support 100 to 300 passengers streaming,’ that range and experience drops to ’50 to 150 simultaneous users’ near the equator (e.g., ±10° latitude).
The proof, as they say, will be in the pudding, as long-haul operators fit their aircraft fleets with the Ku-band Low Earth Orbit (LEO) satellite solution and more passengers share their experiences.
China, meanwhile, is the the first country in the Asia-Pacific region selected to host the World Radiocommunication Conference and, according to Li Lecheng, China’s Minister of Industry and Information Technology, WRC-27’s 4,000 attendees in Shanghai should expect a “grand” event.
“We will fulfill our obligations as the host country in accordance with ITU’s rules and regulations, provide comprehensive services and support for the Conference, and work together with all ITU member states to present to the world a radiocommunication event that fosters win-win cooperation and yields fruitful outcomes,” he said in a statement.
“We hereby extend a cordial invitation to all delegates to the event and wish them all a pleasant stay in Shanghai.”
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Featured image credited to istock.com/yucelyilmaz
