Radio waves

Who can send radio waves into space?

The company now wants to launch a 150-person constellation to communicate with the growing number of internet-connected devices on Earth. Because its satellites are so small and therefore cheap to launch, Swarm estimates that its messaging services will cost an order of magnitude less than existing satellite systems. All it needs is a few slivers of VHF radio spectrum.

However, longtime satellite operator Orbcomm has claimed these frequencies for decades and operates one of the messaging systems that Swarm aims to disrupt. In a petition to the FCC to deny Swarm’s constellation application, Orbcomm wrote that the startup is “attempting to simply ignore Orbcomm’s clearly acquired spectrum rights.”

“There really are scarcity issues in orbit,” says Thomas Hazlett, a Clemson University economics professor and author of The Political Spectrum. “If you want to set up a satellite for communications, you may have potential conflicts with other users. There is a real need for rules to help coordinate this use.

The International Telecommunication Union (ITU) is the body tasked with sorting out these competing claims. Created in the mid-19th century to standardize telegraph technologies, it has helped regulate who can place satellites in orbit since the dawn of the space age. The agency, which also allows phone calls to be made from one country to another, among a myriad of other regulatory responsibilities, is now part of the United Nations. But individual countries also want a say in what spacecraft flies overhead. This means operators like Swarm must also work with national agencies in the countries in which they intend to operate (in particular, the FCC controls access to the all-important US market).

Unsurprisingly, newcomers see these regulations as barriers meant to keep them in the field. In a lengthy response to the FCC, Swarm asserted that Orbcomm has no rights to the spectrum it wishes to use and that the company’s “frivolous” petition “represents nothing more than an attempt by a long-standing monopoly to use the licensing process to maintain its privileges”. .”

Stable circular orbits around the Earth are associated with particular velocities, which vary with altitude. (Satellites in elliptical orbits speed up as they approach Earth and slow down as they reach the farthest point in their orbit.) At 35,786 kilometers (22,236 miles), orbital velocity is the rotation of the Earth. Spacecraft flying directly over the equator at this altitude will appear frozen in the sky to a surface observer. These geostationary slots allow a single large satellite to serve a wide geographic area, whether to relay communications or, for example, to monitor the weather.

Allowing for some wiggle room between neighboring satellites, there are perhaps 1,800 useful geostationary points on this great circle, of which about 400 have taken care of over the years. As you might expect, there is more interest in spots over wealthy regions like North America and Europe than over sparsely populated Pacific islands. Countries were assigned slots above their longitude, and then individual satellites were allowed to set up on a first-come, first-served basis.

Nicolas Ortega

At first, the spectrum seemed like a solvable problem. Not only did the frequencies have to be distributed among a small number of operators in an area, but the same frequencies could be reused over and over again around the world. Everyone understood the rules, says Tim Farrar of satellite consultancy TMF Associates.

The rules of the game change, however. Operators want to pack small, inexpensive satellites on carpool rockets and send them to low Earth orbit, or LEO. Only a few hundred or thousands of kilometers away, satellites equipped with cameras have a much better view of the planet; for communication systems, the shorter distance to the surface can save power and reduce latency. With a multitude of altitudes and orbits to choose from, there should be room for everyone.

Spectrum is now becoming the limiting factor in who can deploy new communications constellations. LEO’s satellites orbit the planet in hours, potentially causing interference not only with each other, but also with any geostationary satellites they pass beneath. Initially, the ITU’s solution was to do the same thing it had done for geostationary orbit: the first operator to request to use a slice of spectrum had priority. All who follow should agree not to interfere.

Spectrum is now becoming the limiting factor in who can deploy new communications constellations.

But interference is a vague concept. “Geostationary coordination is relatively simple,” says Diederik Kelder, director of strategy at LeoSat, which envisions a constellation of at least 84 internet satellites in LEO. ” Whereas in [LEO] it’s a very complex thing. You need very sophisticated modeling tools to capture the impact.

Anticipating a spectrum crisis to come, the FCC decided to move forward with spectrum sharing policies where everyone who was considering using similar frequencies would be accommodated at the same time, which we calls “processing cycles” that would theoretically create a more level playing field.

But there were unintended consequences. Other conflicts have erupted as new entrants try to find regulatory loopholes or technical solutions while established operators try to protect their frequencies from interference, whether real or imagined. The incentive for companies to apply for spectrum as soon as possible also means they must file applications with the ITU and FCC long before their satellites have been built or, in some cases, even fully designed.

SpaceX is the most ambitious of the new LEO generation. In 2015, Elon Musk unveiled a plan to use a mega-constellation of satellites called Starlink to deliver global high-speed internet that would reach many developing and underserved regions. SpaceX initially sought permission to launch 4,425 satellites, but it increased that number to nearly 12,000 in 2017, a constellation the FCC finally cleared in late 2018.

Ahead of the launch of its first commercial satellites, SpaceX changed its plan again, asking to bring some of its satellites closer to Earth and change the frequencies they would use. Its own analyzes apparently showed no new interference, but other satellite companies were unhappy. Kepler, another satellite communications start-up, called its claims “fundamentally misleading”. OneWeb, which plans its own mega-constellation of more than 2,500 internet satellites, also said SpaceX’s interference calculations “[included] misleading operational assumptions, an incomplete set of analysis parameters and highly misleading conclusions.

The FCC approved SpaceX’s plan, and the company launched its first 60 Starlink satellites in May. Its rivals will now have to launch their satellites hoping their interference concerns were unfounded.

At least that spat was quickly settled. The nightmare of newcomers is that litigation can lead to endless regulatory delays.

In 2001, for example, a company called Mobile Satellite Ventures petitioned the FCC to reallocate some of its satellite frequencies to a hybrid satellite/terrestrial communications service. Ten years later, the company, now called LightSquared, received a conditional waiver to sue that was quickly shelved over concerns it could interfere with GPS navigation signals. LightSquared almost immediately filed for bankruptcy, but with the passage of nearly another decade and another name change, Ligado Networks continues LightSquared’s fight. It has promised to reduce the power of its transmissions by more than 99%, but still faces sustained pushback from nervous, even jealous, aerospace competitors.

“Ligado’s decision to waste 40 MHz of satellite spectrum should not be rewarded with a windfall,” rival satellite operator Iridium wrote to the FCC in July 2018. In April, Ligado noted in a meeting with the FCC that the agency was considering its last application for more than 1,000 days. As this issue went to press, the FCC had yet to rule on it.

Nonetheless, Ligado’s approach shows how technology could help quell the feuds. The company was able to significantly reduce its energy needs thanks to increasingly sensitive receivers. Multiplexing systems also continue to improve, due to both improved computing power and increasingly complex intelligent techniques for encoding and decoding signals.

High-gain antennas allow satellites to create focused spot beams targeting specific areas below them. The narrower this focus, the more these frequencies can be reused. Other new systems plan to use even more focused lasers for one satellite to communicate with another, reducing the demand for radio frequencies. New phased array technologies mean that satellite signals can now be received by small, inexpensive electronically controlled flat panel antennas rather than the bulky satellite dishes of yesteryear. GPS-equipped satellites and user terminals can be programmed to avoid transmitting to competing LEO or geostationary satellites.

Some experts say the best way to unleash technological innovation is for regulation to take a back seat to market-based solutions, like existing auctions for terrestrial wireless spectrum. But there is no clear mechanism for such a global spectrum auction.

In any case, while converting free satellite spectrum allocations into tradable rights may offer incentives for cooperation rather than obstruction, it would be a difficult process on a global scale. The orbital economy is already dominated by a handful of the world’s most powerful nations. Granting preferential access to the wealthiest companies seems likely to perpetuate historical inequalities and exclude developing countries that have the most to gain from reaching the next technological frontier.

Not everyone sees the need for a revolution in orbit. Farrar believes that satellites and ground stations will regularly be forced to suspend operations until the risk of interference subsides, significantly reducing their capacity and threatening already fragile business plans. “It would be a disaster from an economic point of view if everyone could work,” he says. “But it is inconceivable that [all these companies] will do what they have announced they plan to do.

In this case, a torturous bureaucracy that postpones, delays, and disrupts business plans might be just what the space needs.

Mark Harris is a writer in Seattle and a frequent contributor.