Correction: Upon further analysis of FCC filings and proposed updates to ITU regulations, SpaceX’s Internet constellation is on much steadier ground than it initially appeared to be, and the FCC decision made on September 26 2017 to update its NGSO FSS regulations is likely to help SpaceX far more than it might harm the company.
The ITU has since 2015 taken a stance that aligns more with the FCC’s cooperative spectrum sharing policy and did not intend for Part 5 of its Radio Regulations to be interpreted as a “first come, first serve” attitude. Specifically, the ITU’s 2017 Rules of Procedure pointedly state in Article 9.6 (Word document download) that those rules were not intended “to state an order of priorities for rights to a particular orbital position” and that “the [interference] coordination process is a two way process”. An ex parte filed with the FCC (PDF download) by SpaceX on September 15 stated SpaceX’s support for these international and domestic policy adoptions, as well as the FCC International Bureau’s responsive consideration of SpaceX’s own suggestions.
The company’s first two test satellites could still launch later this year
The U.S. Federal Communications Commission (FCC) responded September 7th to requests for modification to existing satellite communications regulations and FCC practices from a number of prospective constellation operators, including OneWeb, Telesat, and SpaceX.
The FCC ultimately decided to avoid one major rule change that could force SpaceX to completely reconsider its strategic approach to its proposed Low Earth Orbit broadband constellation.
To grossly oversimplify, SpaceX had requested that the FCC apply their non-interference rules for lower orbit communications satellites to internet constellations operating both inside and outside the physical United States. These rules require that communication satellites operating in non-geostationary orbits (NGSO) share the available wireless spectrum equally among themselves when two or more satellites pass within a certain distance of each other relative to ground stations. In simpler terms, consider your smartphone’s cellular connectivity. The FCC’s rule for satellites in lower orbits can be thought of like multiple smartphones using the same cell tower to access the internet: the cell tower simply acknowledges the multiple devices it needs to serve and allows each device a certain amount of bandwidth.
However, the FCC is admittedly a domestic Commission focused on administering communications rules and regulations in the United States, and an agency already exists for coordinating global communications needs, called the International Telecommunication Union (ITU). The ITU’s Radio Regulations are considerably more simplistic. Rather than the FCC’s more nuanced and reasonable methods of spectrum sharing, the ITU allows the first satellite operator actively using a certain orbit or spectrum to become the primary coordinator for all interference issues. Put more simply, it gives those who launch communications satellites first a “first come, first serve” advantage that lets those entities then set the rules for interference with their constellation.
Both OneWeb and Telesat, companies also interested in launching global broadband constellations, are licensed in countries other than the United States, meaning that the FCC has given the ITU precedent in deciding how to deal with SpaceX’s potential constellation interference. SpaceX’s proposed constellation of at least several thousand satellites ends up being at a distinct disadvantage simply because it would take far longer for SpaceX to even partially complete its constellation when compared with competitors like OneWeb, who expect to finish launching the first phase of their constellation several hundred satellites by the end of 2020. Under the ITU’s regulations, SpaceX could be forced by competitors to effectively step on eggshells around their constellations by avoiding interference to the furthest extent possible, rather than simply sharing spectrum in the brief periods where different satellites temporarily interfere with each other.
While the FCC’s choice to cede international interference coordination to the ITU is a huge blow to SpaceX’s proposed internet constellation efforts, the same September 7th report also eased a handful of other requirements that would have proven difficult for SpaceX’s massive constellation. For geostationary constellations, the FCC previously required that all satellites be launched within a period of six years, with failure to do so resulting in a revoked license for the company in question. In a small concession to SES, O3b, and SpaceX, the FCC now plans to require that 50% of lower orbit satellite constellations be launched within six years of receiving an FCC license. This would still be a massive challenge for SpaceX’s plan of 4,425 initial satellites and a follow-up constellation of more than 7,000 additional satellites (PDF download).
The FCC’s September 7th report will not become final unless it is passed by vote in a September 26th Open Commission Meeting. It is possible that SpaceX council will make a statement protesting the FCC’s decision, but it is nevertheless likely that the FCC’s report will be accepted and become official. While the LEO internet constellation has remained a low priority for SpaceX since it was revealed in 2015, the company has steadily continued work on the project and SpaceX has every reason to continue pursuing it given the potential profit margins it could produce. In spite of the now expanded difficulties lying ahead, SpaceX appears to be preparing for the first launch of two test satellites related to its internet constellation efforts. The move is seen as a likely attempt to tag along as passengers during SpaceX’s launch of PAZ, a Spanish earth imaging satellite, during the final three months of 2017.
Elon Musk is scheduled to reveal more details on SpaceX’s Mars exploration and colonization efforts on September 29th. He has stated that this presentation will focus more on the “how” of colonizing Mars, revealing how exactly SpaceX thinks it can fund the development of its Interplanetary Transport System. Musk also confirmed several weeks ago that SpaceX had reduced the size of the ITS rocket to a still-massive diameter of 9 meters, and sources inside the company have also indicated that the company is thinking about modifying its LC-39A Florida launch pad to support both Falcon and ITS vehicles. SpaceX recruiters revealed earlier this week that SpaceX also intends to have their Boca Chica, Texas launch pad, which is currently under construction, be capable of eventually launching ITS-sized vehicles once it comes online in 2019 or later.
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If SpaceX must comply with international radio communications rules, and they are forced to defer to other satellite providers over spectrum interference, might this be a spur to develop innovations in satellite-to-ground and satellite-to-satellite communications?
I'm thinking specifically of laser-based communications. If anyone on the planet can achieve the perfect alignments required, it would be SpaceX. They can land first-stage rockets on their tails in a tight space! Nobody else can control their space machines with that kind of precision.
With laser-based commo, there would be no interference at all with neighboring satellites, except during occlusions, which should be rare and extremely brief (fractions of a second). Choose spectra that will slice through CO2, water, nitrogen, oxygen, dust, etc and which will not interact with the lenses of human eyeballs. The lasers need not be high power to achieve high bandwidth.
By going into the high optical bands, SpaceX might be able to bypass both FCC and international rules for radio band communications. and perhaps provide superior throughput as well.
Feasible? Beats me, I'm not an optical engineer. Perhaps SpaceX will have to rule it out, but I'd enjoy knowing that they at least looked at the idea.
I think your solution is quite literally a "blue sky" proposal. Not workable in the real world with current or even foreseeable technology.
NASA has been pushing ahead the state of the art for space-based laser communication for years now, and has conducted deep-space and through-atmospheric tests and demonstrations. But the state-of-the art we have reached today for lasers in space applications appears to fall short of what would be required in a thousands-of-satellites constellation, intercommunicating with each other and with the ground from low Earth orbit. It's much easier from Geosynch with a fixed ground target (pick a ground location most often free of clouds) or with communications between only two or three devices (fewer moving parts).
There are some more-than-merely-theoretical advantages to lasers in space. Working with microwave radio, big antennas and high power are required to communicate from orbit, and interference with other transmitters is an issue. Laser wave guides operating at much higher frequency can be smaller and can push much higher volumes of data with much lower power requirements, and interference issues are reduced drastically.
I'm asking myself, what would SpaceX need to innovate, in order to avoid radio interference with other satellite operators, in a low Earth orbit constellation of satellites?
1. They would require operating frequencies for their lasers that avoid atmospheric absorption and that can use adaptive optics to avoid distortion. I think those bands may exist in the far infrared and X-ray frequencies. (Both of which are relatively embryonic in laser research, as opposed to optical-band lasers, which are mature.)
2. The lasers can't be fixed devices that require the satellite itself to do the pointing - because multiple lasers will be needed to point at other moving satellites and ground stations that are moving relative to each satellite. Each laser will have to point dynamically. Perhaps there are engineering solutions for this that avoid lots of mechanical moving parts, but it's a lot to ask of engineers.
3. There won't be direct satellite-to-customer links, because that would require too many lasers on each satellite; ground stations will have to be the targets for lasers. This means that there will have to be ground-based radio, fiber or cable communications with customers.
Therefore, even if the engineering challenges can be solved for satellite lasers and ground stations, SpaceX would be stuck with the need to either lease ground-based transmission over cables to reach customers, or have to fight through interference questions (and maybe spectrum leasing) with a ground-based radio operation. Which sort of puts them back to square one; that's the problem they're wrestling with now for radio transmissions. SpaceX might avoid interference with other satellites by using lasers; but they still would have to work with radio on the ground if they adopt a laser approach for their satellites, or pay through the nose for land-based transmission (which won't even work in some parts of the world).
On first blush, it seems to me that though laser communications holds some potential going forward, it won't be easy, by any means, to productively use lasers in SpaceX's constellations in the near future. My opinion shouldn't carry any weight, though. I'm far from possessing any sort of expertise.
If you asked me ten years ago if a launch company would be landing first stage rockets on their tails in the near future, I'd have laughed. I'm now understandably hesitant to be the one who declares that a particular engineering challenge is too hard for SpaceX. (I try never to miss a launch webcast by SpaceX; I'm still agog at each success they achieve.)
Blessing in disguise, perhaps?
If SpaceX must comply with international radio communications rules, and they are forced to defer to other satellite providers over spectrum interference, might this be a spur to develop innovations in satellite-to-ground and satellite-to-satellite communications?
I'm thinking specifically of laser-based communications. If anyone on the planet can achieve the perfect alignments required, it would be SpaceX. They can land first-stage rockets on their tails in a tight space! Nobody else can control their space machines with that kind of precision.
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Laser-based comms would be awesome for satellite to satellite comms (not only they offer enormous bandwidth advantages, they are also more energetically efficient and practically impossible to intercept) but they are not good for ground to satellite. In perfect conditions thwy could be challenging but feasible (you would have to have active tracking, be in an open space, protect from possible harm to humans and animals, etc.) but even a simple cloud completely blocks your communications, in addition to rain and fog. However awesome SpaceX is, they can't change the fact that clouds are not transparent to visible or infrared light. Ultraviolet lasers could be an option, but they are extremely dangerous, expensive and still would fail in the rain (and need to be placed outdoors, have active tracking, etc.).
So I think until we have made serious progress in quantum communications (at which point, who needs satellites?) it will be RF, and they will have to share. The good news, I think, is that given SpaceXs ability to launch satellites at a lower cost, if they play their cards rights, they can probably outmaneuver their competitors which would have lower ROI for the same spectrum, so they will be forced to make reasonable deals (no one has exclusivity on the whole spectrum globally, so SpaceX can shop around, at least until their satellites are up there).
Laser-based comms would be awesome for satellite to satellite comms (not only they offer enormous bandwidth advantages, they are also more energetically efficient and practically impossible to intercept) but they are not good for ground to satellite. In perfect conditions thwy could be challenging but feasible (you would have to have active tracking, be in an open space, protect from possible harm to humans and animals, etc.) but even a simple cloud completely blocks your communications, in addition to rain and fog. However awesome SpaceX is, they can't change the fact that clouds are not transparent to visible or infrared light. Ultraviolet lasers could be an option, but they are extremely dangerous, expensive and still would fail in the rain (and need to be placed outdoors, have active tracking, etc.).
So I think until we have made serious progress in quantum communications (at which point, who needs satellites?) it will be RF, and they will have to share. The good news, I think, is that given SpaceXs ability to launch satellites at a lower cost, if they play their cards rights, they can probably outmaneuver their competitors which would have lower ROI for the same spectrum, so they will be forced to make reasonable deals (no one has exclusivity on the whole spectrum globally, so SpaceX can shop around, at least until their satellites are up there).
I agree that the visible optical spectrum isn't going to work. UV won't work, either. Both would be dangerous to human and animal eyeballs. It's less clear to me that x-ray or far infrared bands aren't usable for space-to-ground communications, though the engineering for such systems is very far from trivial. It's sure not an off-the-shelf proposition.
Quantum communications is not a cure-all: you still have to generate photons and send them to a receiver, and that means you have the same challenge of getting past absorbing molecules in the atmosphere, and the same challenge of aligning transmitters to receivers.
Perhaps you are thinking of using entanglement for communications? But that's even worse. For entanglement, you need close proximity for subatomic particles or photons to generate entanglement; then you need to separate them and solve the problem of keeping them entangled for long periods; but you'll have a finite supply to exploit for communications, and each communications capability created through entanglement is two-way only, not what you want for a mesh network. And technologically, this is far, far out, much harder than far-infrared or x-ray lasers, if it's feasible at all.
For purposes of our understanding, it's important not to confuse quantum communications with entanglement communications. They aren't the same thing, though both deal with quantum physics. With quantum communications, actual photons are sent between transmitter and receiver, then evaluated for their quantum properties which carry data. Entanglement, in theory, dispenses with the need to move particles (even photons) at all.
