TAMPA, Fla. — A proposal to review satellite power limits set more than a decade ago to avoid signal interference between different orbits is one of the most divisive among operators ahead of WRC-23, a four-week meeting kicking off Nov. 20 in Dubai to update global spectrum rules.
These limits, known as Equivalent Power Flux Density (EPFD) limits, cap non-geostationary satellite power to avoid disrupting the geostationary spacecraft they fly under while passing over the equator.
Approving the proposal to review EPFD rules at WRC-23 would see the United Nations’ International Telecommunication Union (ITU) study these limits and — depending on the results of those studies — propose regulatory changes that would be up for debate at the next conference in 2027.
Amazon announced a coalition with three think tanks Oct. 31 to push delegations heading to WRC-23 to adopt the proposal to review EPFD rules, which were first put into radio regulations back in 1997 on a provisional basis.
The rules do not account for improvements in satellite technology and spectrum management principles over the years, according to the Alliance for Satellite Broadband, and ultimately reduce the availability and increase the cost of broadband services from non-geostationary orbit (NGSO).
Julie Zoller, head of global regulatory affairs for the Project Kuiper broadband constellation Amazon is plotting in low Earth orbit (LEO), said outdated EPFD rules constrain NGSO systems more than is necessary to protect their counterparts in geostationary orbit.
Executives from satellite operators SES and Telesat sparred over the proposal to review EPFD rules during a Nov. 7 webinar on the WRC-23 agenda hosted by SpaceNews.
Luxembourg-based SES operates satellites in geostationary and medium Earth orbit. Telesat of Canada is a geostationary operator planning to deploy commercial LEO broadband satellites in 2026.
EPFD rules already strike the right balance between protecting geostationary satellites and enabling competition from NGSO newcomers, said Anna Marklund, director of spectrum management and development at SES, who pointed to large constellations such as SpaceX’s Starlink and those in the works by the likes of Amazon.
It took a lot of time and effort to establish EPDF rules, and Marklund said reviewing them would be a significant drain on resources better spent on more pressing spectrum issues.
“Satellite technology development is not tied to the EPFD,” she added.
Instead, she said the technology advances seen in NGSO are linked to types of orbits, which remain largely unchanged from when EPFD rules started to be developed two decades ago.
“The rules were written a long time ago and they’re worth revisiting,” countered Elisabeth Neasmith, Telesat’s senior director for regulatory issues.
While maybe nothing would change following the review, she said the proposal needs to be adopted at WRC-23 in order to have the conversation.
Marklund asserted SES is not opposed to having a conversation around reviewing EPFD rules, but that the time is not right to prioritize the review during treaty-level negotiations for changing spectrum rules.
Still, it might be better to refine EPFD rules so they address the protection of specific geostationary satellites rather than an entire geostationary arc that is seeing less activity amid a shift toward NGSO systems, according to Ruth Pritchard-Kelly, a principal at satellite regulation specialist RPK Advisors.
Pritchard-Kelly is a former head of regulatory affairs at SES and also at OneWeb, the LEO operator that recently merged with Eutelsat.
The proposal also has implications for ensuring equitable access to space, noted Jennifer Manner, senior vice president of regulatory affairs at EchoStar, a U.S.-based geostationary operator planning to start deploying 28 LEO satellites next year for connecting remote Internet of Things (IoT) devices.
Specifically, it would impact spectrum bands set aside in geostationary orbit for countries to use once they are ready. Manner said “I’d be shocked if the developing world didn’t weigh in on this” as they face losing orbital rights.
The EPFD issue underlines the complexity of negotiations facing WRC-23 delegates this year, said Katherine Gizinski, CEO of space consultancy firm River Advisers.
Ultimately, she said it’s important the WRC-23 negotiation process works as intended, and that all the various facets of issues on the agenda are considered as regulators seek a cohesive regulatory playing field for satellite and terrestrial communications.