U.S. and international regulators are facing tough decisions on how to balance the promise of universal broadband access with the threat of satellite in-orbit collisions and frequency interference from proposed constellations of low-orbiting satellites. Credit: ESA

PARIS — SpaceX’s planned constellation of 4,425-satellites for direct-to-home internet delivery has come under fire by competitors who want regulators to reject SpaceX’s request for a waiver of in-service and coverage deadlines.

Several competitors are also asking that any decision on the SpaceX system be delayed pending a review of the measures SpaceX says it will take to avoid signal interference with neighboring low-orbit satellites and satellites in the higher geostationary orbit.

The companies are complaining that SpaceX waited until July 12 to submit a detailed, public interference-mitigation plan. The U.S. Federal Communications Commission (FCC), as part of an ongoing review of 10 companies’ low-orbit broadband proposals, had set a July 14 deadline for this round of comments.

The 10 applicants range from established fleet operators such as Intelsat, SES’s O3b, Telesat and ViaSat, to satellite startups including Audacy Corp., Karousel LLC, Space Norway AS, Theia Holdings A Inc. and LeoSat MA Inc. as well as SpaceX. Boeing Co. has an application for a constellation as well, although Boeing has not been clear on its intentions as to system ownership and operation.

10 little Indians now, plus OneWeb

How many of these 10 companies will be able to secure the financial support needed to build their systems is uncertain at this point. One company, OneWeb, has already received FCC approval and has raised some $1.7 billion, which is likely less than half of what it will need to deploy its full network of around 800 satellites.

Also unclear is how many of these systems the FCC will approve, and whether the commission will account for the space traffic-management and debris challenges inherent in licensing thousands of satellites orbiting close to one another.

SpaceX’s constellation is by far the largest, which is one reason it attracts the attention of its competitors. A 4,425-satellite fleet is under special pressure with respect to space traffic management, space debris mitigation and the removal from orbit of its spacecraft at the end of their service lives.

SpaceX has left itself open to a particular attack by admitting that although it can begin to generate revenue with just 800 satellites, even when 1,600 are in orbit it will not be able to cover the whole of U.S. territory — a sensitive point with the U.S. regulator.

SpaceX has said its network is still evolving but for now it has described a system using Ku-band for user links, with satellites orbiting in five orbital planes at altitudes of between 1,110 and 1,325 kilometers.

Each satellite is expected to weigh 386 kilograms at launch, with phased-array beam-forming antennas, optical inter-satellite links and enough fuel to assure that each spacecraft is directed into the Earth’s atmosphere at the end of its five- to seven-year operating life.

The company has specifically said it would reserve propellant to power its retiring satellites to an altitude of 300 kilometers — below the International Space Station — before shutting them down and letting them burn up on reentry into the Earth’s atmosphere.

For comparison, each OneWeb satellite is expected to weigh 150 kilograms at launch, with conventional antennas and no inter-satellite links.

Under FCC regulations, all non-geostationary-orbit constellation operators must commit to having their full system in orbit within six years of being licensed.

SpaceX: We can’t launch 4,425 satellites – 1.7 million kilograms’ worth – in 72 months

SpaceX and Boeing, which is designing its own low-orbit constellation, have told the FCC they cannot make this deadline. They argue they should be allowed to operate even if they can only launch a piece of their constellation in the six-year limit.

Even SpaceX, a launch-service provider with better rocket access than most satellite operators, cannot complete the launch 4,425 satellites — more than 1,700 metric tons of satellite hardware — within six years of its license.

Alaska’s total population is around 750,000. SpaceX says its satellite constellation won’t cover the northernmost part of the state until sometime after the regulatory deadline. Is that a problem? Credit: Oak Ridge National Laboratory

Instead, it wants approval to launch 1,600 satellites within the six-year deadline, with the remaining 2,825 satellites in operation sometime after that.

Full coverage of Alaska would have to wait for the second phase of launches as the first 1,600 will be at lower orbital inclinations relative to the equator and will not cover the whole of the state, SpaceX says.

The FCC and the International Telecommunication Union (ITU), a United Nations organization that regulates wireless radio spectrum and satellite orbital slots, make in-service deadlines a part of their regulatory processes to avoid situations where operators “warehouse” radio spectrum.

This has happened in the past, where an operator will maintain rights to given frequencies for years without making serious progress on launching anything.

SpaceX responds that a company launching 1,600 satellites in a six-year period has already demonstrated its seriousness and cannot be accused of warehousing spectrum.

But other operators, including OneWeb, SES/O3b and Intelsat, are urging the FCC not to ease this requirement.

FCC reviewing changes to constellation milestones

In parallel, the FCC is debating whether to restructure its deployment deadline to account for the unique nature of the new constellations. One idea is to establish a two-step process where a percentage of the constellation must be in service within six years, and the remaining satellites launched within nine years of the license.

The size of the SpaceX constellation also makes it a center of attention with respect to space traffic management and orbital debris.

OneWeb, for example, is worried that some of SpaceX’s satellites will operate too closely to OneWeb’s given the imprecision of orbit determination.

OneWeb and Boeing recently reached an agreement to create more space between their constellations to reduce collision risk:

http://bit.ly/2vu5Iyi

SpaceX told the FCC on July 7 that the Boeing-OneWeb agreement had the effect of placing Boeing’s constellation just 28 kilometers below part of SpaceX’s.

SpaceX has proposed that all operators of low-orbiting constellations agree to share precise satellite-location data with each other.

U.S. and international regulators agree that all non-geostationary-orbit constellations must agree not to interfere with the established networks of satellites in geostationary orbit.

To do this, the ITU asks constellation operators to agree to switch off their satellites when their broadcasts are directed at the same places as geostationary satellites, especially around the equator.

The metric established by the ITU is called equivalent power-flux density (EPFD).

SpaceX said its system meets the EPFD requirements but that proof of this was not disclosable publicly because it was new and proprietary to Transfinite Systems of Britain. It agreed to submit the software program to the FCC on a confidential basis.

On July 12, SpaceX submitted the public version. Several competitors said on July 14 that they would need more than two days to assess it.