Disclaimer. The article is supplemented, corrected and updated translation Nathan Hurst. Some information from the article about when building the final material.
There is a theory (or perhaps a cautionary tale) among astronomers called the Kessler syndrome, named after the NASA astrophysicist who proposed it in 1978. In this scenario, an orbiting satellite or some other object accidentally strikes another and breaks into pieces. These parts revolve around the Earth at a speed of tens of thousands of kilometers per hour, destroying everything in their path, including other satellites. It sets off a catastrophic chain reaction that ends in a cloud of millions of pieces of dysfunctional space junk that orbits the planet endlessly.
Such an event could render near-Earth space useless, destroying any new satellites sent into it and possibly blocking access to space altogether.
So when SpaceX (Federal Communications Commission - Federal Communications Commission, USA) to send 4425 satellites into low Earth orbit (LEO, low-Earth orbit) to provide a global high-speed Internet network, the FCC was concerned about this. More than a year company commissions and petitions by competitors to deny the application, including filing an "orbital debris reduction plan" to allay fears of a Kessler apocalypse. On March 28, the FCC granted SpaceX's application.
Space debris isn't the FCC's only concern, and SpaceX isn't the only organization trying to build next-generation satellite constellations. A handful of companies, both new and old, are embracing new technologies, developing new business plans and petitioning the FCC for access to the portions of the spectrum they need to cover the Earth with fast, reliable Internet.
Big names are involved - from Richard Branson to Elon Musk - along with big money. So far, Branson's OneWeb has raised $1,7 billion, with SpaceX President and COO Gwynne Shotwell estimating the cost of the project at $10 billion.
Of course, there are big problems, and history says that they affect quite unfavorably. The good guys are trying to bridge the digital divide in underserved regions, while the bad guys are putting illegal satellites on rockets. And all of this is happening because demand for data delivery is skyrocketing: in 2016, global internet traffic topped 1 sextillion bytes, according to a Cisco report, ending the era of zettabytes.
If the goal is to provide good Internet access where there was none before, then satellites are a smart way to achieve this. In fact, companies have been doing this for decades with large geostationary satellites (GSOs), which are in very high orbit, where the rotation period is equal to the Earth's rotation speed, due to which they are fixed over a certain region. But except for a few narrowly focused tasks, such as surveying the Earth's surface with 175 low-orbit satellites and transmitting 7 petabytes of data to Earth at a speed of 200 Mbps, or the task of tracking cargo or providing network access to military bases, this type of satellite communication was not fast and reliable enough to compete with today's fiber optic or cable internet.
Non-geostationary satellites (Non-GSOs) include satellites that operate in medium earth orbit (Medium Earth orbit, MEO) at altitudes from 1900 to 35000 km above the Earth's surface, and low earth orbit satellites (Low Earth orbit, LEO), whose orbits are located on altitudes less than 1900 km. Today, LEOs are becoming extremely popular and in the near future it is expected that if not all satellites will be like this, then most certainly.
Meanwhile, regulations for non-geostationary satellites have been around for a long time and are divided between agencies inside and outside the US: NASA, FCC, DOD, FAA, and even the UN International Telecommunications Union are all in this game.
However, from a technological standpoint, there are some big advantages. The cost of building a satellite has fallen as gyroscopes and batteries have improved due to the development of cell phones. They also became cheaper to launch, thanks in part to the smaller size of the satellites themselves. Capacity has risen, inter-satellite communications have made systems faster, and big dishes pointing to the sky are already going out of style.
11 companies have filed with the FCC, along with SpaceX, each tackling the problem in its own way.
Elon Musk announced the SpaceX Starlink program in 2015 and opened a branch of the company in Seattle. He told employees, "We want to revolutionize the satellite communications system in the same way as rocket science."
In 2016, the company filed an application with the US Federal Communications Commission seeking permission to launch 1600 (subsequently reduced to 800) satellites between now and 2021, and then launch the rest until 2024. These near-Earth satellites will be in 83 different orbital planes. The constellation, as the group of satellites is called, will communicate with each other via on-board optical (laser) links so that data can be reflected across the sky instead of returning to the ground - passing over a long "bridge" rather than going up and down.
On the ground, customers will be installing a new type of terminal with electronically steerable antennas that will automatically connect to the satellite that currently offers the best signal—similar to how a cell phone selects towers. Since the LEO satellites are moving relative to the Earth, the system will switch between them every 10 minutes or so. And since there will be thousands of people using the system, there will always be at least 20 available to choose from, according to Patricia Cooper, vice president of satellite operations at SpaceX.
The ground terminal should be cheaper and easier to install than traditional satellite dishes, which must be physically oriented to the part of the sky where the corresponding geostationary satellite is located. SpaceX says the terminal will be no bigger than a pizza box (although it doesn't specify how big the pizzas are).
Communication will be provided in two bands of the frequency spectrum: Ka and Ku. Both belong to the radio spectrum, although they use much higher frequencies than those used for stereo. Ka-band is the higher of the two, with frequencies between 26,5 GHz and 40 GHz, while Ku-band is located from 12 GHz to 18 GHz in the spectrum. Starlink has received FCC approval to use certain frequencies, normally the uplink from the terminal to the satellite will operate from 14GHz to 14,5GHz and the downlink from 10,7GHz to 12,7GHz and the rest will be used for telemetry, tracking and control, as well as to connect satellites to the terrestrial Internet.
Aside from the FCC filings, SpaceX has kept quiet and hasn't been public about its plans yet. And it's hard to know any of the technical details, because SpaceX runs the entire system, from the components that will be used on the satellites to the rockets that will take them into the sky. But for the success of the project, it will depend on whether the service can, it is claimed, offer speeds comparable to or better than fiber at a similar price, along with reliability and a good user interface.
In February, SpaceX launched its first two prototype Starlink satellites, which are cylindrical in shape with winged solar panels. Tintin A and B are about a meter long, and Musk confirmed via Twitter that they successfully communicated. If the prototypes continue to function, hundreds of others will join them by 2019. Once the system is in service, SpaceX will replace decommissioned satellites on a permanent basis, to prevent space debris, the system will instruct them to lower their orbits at a certain point in time, after which they will begin to fall and burn up in the atmosphere. Below in the figure you can see what the Starlink network looks like after 6 launches.
A bit of history
Back in the 80s, HughesNet was an innovator in satellite technology. Do you know the dish-sized gray antennas that DirecTV puts up outside houses? They hail from HughesNet, which itself came into existence thanks to aviation pioneer Howard Hughes. “We've invented technology that allows us to provide interactive communications via satellite,” says EVP Mike Cook.
In those days, the then Hughes Network Systems owned DirecTV and operated large geostationary satellites that relayed information to television sets. Then and now, the company also offered services to businesses, such as processing credit card transactions at gas stations. The first commercial customer was Walmart, which wanted to link employees across the country to a home office in Bentonville.
In the mid-90s, the company created a hybrid Internet system called DirecPC: the user's computer sent a request over a dial-up connection to a web server and received a response via a satellite that transmitted the requested information down to the user's dish at a much faster speed than the dial-up connection could provide .
Around 2000, Hughes began offering bi-directional network access services. But keeping the cost of the service, including the cost of client hardware, low enough for people to buy it was a challenge. To do this, the company decided that it needed its own satellites, and in 2007 it launched Spaceway. The satellite, still in use today, was especially important at launch, Hughes said, as it was the first to support onboard packet switching technology, essentially the first space switch to remove the extra hop in the form of a ground station for communication. subscribers among themselves. Its capacity is over 10 Gb/s, 24 transponders of 440 Mb/s, allowing individual subscribers to have up to 2 Mb/s for transmission and up to 5 Mb/s for download. Spaceway 1 was manufactured by Boeing on the basis of the Boeing 702 satellite platform. The launch weight of the device was 6080 kg. Spaceway 1 is currently one of the heaviest commercial spacecraft (SC) - it broke the record of the Inmarsat 5 F4 satellite (1 kg) launched using the Atlas 5959 launch vehicle (2018 kg), a month earlier. While the heaviest commercial GSO, according to Wikipedia, launched in 7, has a mass of 2 tons. The device is equipped with a relay payload (PN) Ka range. PN includes a controlled 1500-meter phased antenna array, consisting of XNUMX elements. PN forms a multi-beam coverage to ensure the broadcasting of various TV programs in different regions. Such an antenna allows flexible use of spacecraft capabilities in changing market conditions.
Meanwhile, a company called Viasat spent about a decade in research and development before launching its first satellite in 2008. This satellite, called ViaSat-1, included some new technologies such as spectrum reuse. This allowed the satellite to choose between different bandwidths in order to transmit data to Earth without interference, even if it was transmitting data along with a beam from another satellite, it could reuse this spectral range in connections that are not adjacent.
This provided greater speed and performance. When it was commissioned, Viasat president Rick Baldridge said it had a capacity of 140 Gbps — more than all other satellites combined that cover the US.
"The satellite market was really meant for people who didn't have a choice," Baldrige says. “If you couldn't access it any other way, this was the technology of last resort. In fact, it had ubiquitous coverage, but did not really allow much data to be transmitted. Therefore, this technology was mainly used for tasks such as transactions at gas stations.
Over the years, HughesNet (now owned by EchoStar) and Viasat have built faster and faster geostationary satellites. HughesNet released EchoStar XVII (120Gbps) in 2012, EchoStar XIX (200Gbps) in 2017, and plans to launch EchoStar XXIV in 2021, which the company says will offer 100Mbps to consumers.
ViaSat-2 was launched in 2017 and now has a capacity of around 260Gbps, and three different ViaSat-3s are planned for 2020 or 2021, each covering a different part of the globe. Viasat said that each of the three ViaSat-3 systems is predicted to have a capacity of terabits per second, twice that of all other Earth-orbiting satellites combined.
“We have so much capacity in space that it changes the whole dynamic of delivering this traffic. There are no limits on what can be provided,” says DK Sachdev, a satellite and telecommunications technology consultant who works for LeoSat, one of the companies launching the LEO constellation. “Today, all the shortcomings of satellites are being eliminated one by one.”
This whole speed race is no coincidence, as the Internet (two-way communication) has begun to replace television (one-way communication) as a service that uses satellites.
“The satellite industry has been in a very long-term frenzy figuring out how it will transition from unidirectional video transmission to full data transmission,” says Ronald van der Breggen, director of compliance at LeoSat. "There are many opinions about how to do it, what to do, what market to serve."
One problem remains
Delay. Unlike overall speed, latency is the amount of time it takes for a request to travel from your computer to the destination and back. Let's say you click on a link on a website, this request must reach the server and return back (that the server has successfully received the request and is going to give you the requested content), after which the web page is loaded.
How long the site takes to load depends on your connection speed. The time it takes to complete the download request is the latency. It is usually measured in milliseconds, which is why it is not noticeable when you are browsing the web, but it matters a lot when you play online games. However, there are facts when users from the Russian Federation managed and manage to play some of the games online even when the latency (ping) indicator is close to one second.
The delay in a fiber optic system depends on the distance, but usually amounts to several microseconds per kilometer, while the equipment contributes the main latency, although with optical links of considerable length, the delay is more significant due to the fact that in a fiber optic communication line (FOCL) the speed of light is only 60% of the speed of light in a vacuum, and also very dependent on wavelength. According to Baldrige, the latency when you send a request to a GSO satellite is about 700ms - light travels faster in the vacuum of space than in a fiber, but these types of satellites are far away, which is why it takes so long. In addition to gaming, this problem is significant for videoconferencing, financial transactions and the stock market, IoT control, and other applications that depend on the speed of interaction.
But how significant is the latency issue? Most of the bandwidth used worldwide is dedicated to video. Once the video is running and properly buffered, latency doesn't matter much, and speed becomes more important. Not surprisingly, Viasat and HughesNet tend to minimize the importance of latency for most applications, although both are working to minimize it in their systems as well. HughesNet uses an algorithm to prioritize traffic based on what users are paying attention to in order to optimize data delivery. Viasat has announced the introduction of a constellation of Medium Orbital Satellites (MEO) to complement its existing network, which should reduce latency and expand coverage, including at high latitudes where equatorial GSOs have more latency.
“We're really focused on high volume and very, very low capital costs to deploy that volume,” Baldrige says. "Is latency as important as other features to the market we support"?
Nevertheless, there is a solution, LEO satellites are even much closer to users. So companies like SpaceX and LeoSat have taken this path, planning to deploy a constellation of much smaller, closer satellites, with an expected latency of 20 to 30 milliseconds for users.
"It's a trade-off in that because they're in a lower orbit, you get less latency from the LEO system, but you have a more complex system," Cook says. “To complete a constellation, you need to have at least hundreds of satellites, because they are in low orbit, and they move around the Earth, going faster over the horizon and disappearing ... and you need to have an antenna system that can track them.”
But it is worth remembering two stories. In the early 90s, Bill Gates and several of his partners invested about a billion dollars in a project called Teledesic to bring broadband to regions that could not afford network or would not soon see fiber. It was necessary to build a constellation of 840 (subsequently reduced to 288) LEO satellites. Its founders talked about solving the problem of latency and in 1994 approached the FCC to use the Ka-band spectrum. Sounds familiar?
Teledesic ate an estimated $9 billion before it failed in 2003.
“This idea didn’t work then because of the high cost of maintenance and services for the end user, but it seems that it is feasible now,” says , professor of information systems at California State University Dominguez Hills, who has been monitoring LEO systems ever since Teledesic came into existence. "Technology wasn't advanced enough for that."
Moore's Law and improvements in cell phone battery, sensor and processor technology have given the LEO constellations a second chance. Increased demand makes the economy look enticing. But while the Teledesic saga played out, another industry gained some important experience in launching communications systems into space. In the late 90s, Iridium, Globalstar and Orbcomm jointly launched over 100 low earth orbit satellites to provide cell phone coverage.
“It takes years to create a whole constellation because you need a whole bunch of launches and it’s really expensive,” says Zack Manchester, assistant professor of aeronautics and astronautics at Stanford University. “In the intervening time, say five years or so, the terrestrial cell tower infrastructure has expanded to the point where the coverage is really good and has reached most of the people.”
All three companies quickly went bankrupt. And while each has reinvented itself by offering a smaller range of services for specific purposes, such as emergency beacons and cargo tracking, none have succeeded in replacing tower-based cell phones. For the past few years, SpaceX has been launching satellites for Iridium under contract.
“We've seen this film before,” says Manchester. “I don’t see anything fundamentally different in the current situation.”
Competition
SpaceX and 11 other corporations (and their investors) have a different opinion. OneWeb is launching satellites this year and services are expected to start as early as next year, with more constellations to be added in 2021 and 2023 with an end goal of 1000 Tbps by 2025. O3b, now a subsidiary of SAS, has a constellation of 16 MEO satellites that has been in operation for several years. Telesat already operates GSO satellites, but is planning a LEO system for 2021 that will have optical links with 30 to 50 ms latency.
Upstart Astranis also has a satellite in geosynchronous orbit and will be accommodating more in the next few years. While they don't solve the problem of latency, the company is looking to drastically reduce costs by working with local ISPs and building smaller and much cheaper satellites.
LeoSat also plans to launch the first series of satellites in 2019 and complete the constellation in 2022. They will fly around the Earth at an altitude of 1400 km, connect with other network satellites using optical communication and transmit information up and down in the Ka-band. They have acquired the required spectrum internationally, says Richard van der Breggen, chief executive officer of LeoSat, and is awaiting FCC approval soon.
Much of the push for faster satellite internet was based on building bigger, faster satellites capable of transmitting more data, van der Breggen said. He calls it a "pipe": the bigger the pipe, the more the Internet can break through it. But companies like his are finding new areas for improvement by changing the whole system.
"Imagine the smallest type of network - two Cisco routers and a wire between them," says van der Breggen. “What all satellites do is provide a wire between two boxes… we will carry the entire set of three elements into space.”
LeoSat plans to accommodate 78 satellites, each the size of a large dining table and weighing around 1200 kg. Built by Iridium, they are equipped with four solar panels and four lasers (one at each corner) to connect to neighbors. This is the connection that van der Breggen considers the most important. Historically, satellites reflected the V-shaped signal from the ground station to the satellite and then to the receiver. Since the LEO satellites are lower, they cannot project that far, but they can transmit data between themselves very quickly.
To understand how this works, it's helpful to think of the Internet as something that has a real physical entity. It's not just data, it's where that data lives and how it moves. The Internet is not stored in one place, there are servers all over the world that contain some of the information, and when you access them, your computer pulls data from the nearest one that has what you are looking for. Where is it important? How big does it matter? Light (information) propagates in space almost twice as fast as in a fiber. And when you run a fiber connection around a planet, it has to take a detour from node to node with detours around mountains and continents. Satellite Internet does not have these shortcomings, and when the data source is far away, despite the addition of a couple of thousand miles of vertical distance, the delay in trying LEO will be less than the delay in the case of fiber optic Internet. For example, a ping from London to Singapore could be 112ms instead of 186, which would greatly improve connectivity.
As van der Breggen describes the challenge, an entire industry can be seen as the development of a distributed network no different from the Internet as a whole, just in space. Latency and speed both play a role.
While one company's technology may be superior, this is not an antagonistic game, and there are no winners and no losers. Many of these companies target different markets and even help each other achieve the results they expect. For some it's ships, planes or military bases, for others it's rural consumers or developing countries. But ultimately, companies share a common goal: to build the Internet where there isn't, or where there isn't enough, and to do so at a cost low enough to support their business model.
“We think it's not really a competing technology. We believe that both LEO and GEO technologies are needed in some sense,” says HughesNet's Cook. “For certain types of applications, such as streaming video, for example, the GEO system is very, very cost-effective. However, if you want to use low latency applications… then LEO is the way to go.”
In fact, HughesNet has partnered with OneWeb to provide a gateway technology that manages traffic and communicates with the system over the Internet.
You may have noticed that LeoSat's proposed constellation is almost 10 times smaller than SpaceX's. That's okay, says Van der Breggen, because LeoSat intends to serve corporate and government customers and will only cover a few specific areas. O3b sells Internet to cruise ships, including the Royal Caribbean, and partners with telecom providers in American Samoa and the Solomon Islands, where wired high-speed connections are scarce.
A small start-up from Toronto called Kepler Communications uses tiny CubeSats (the size of a loaf of bread) to provide network access for customers who are not demanding on latency, 5 GB of data or even more can be obtained in a 10 minute period, which is relevant for polar research, science , industry and tourism. So, when installing a small antenna, the speed will be up to 20 Mbps for upload and up to 50 Mbps for download, but if you use a large "dish", then the speeds are higher - 120 Mbps for upload and 150 Mbps for reception . According to Baldridge, Viasat's strong growth comes from providing the Internet to commercial airlines; they signed deals with United, JetBlue and American, as well as Qantas, SAS and others.
How, then, will this profit-driven business model bridge the digital divide and bring the Internet to developing countries and underserved populations who may not be able to pay as much for it and are willing to pay less? This will be possible due to the format of the system. Since the individual satellites of the LEO constellation (low orbit satellites) are in constant motion, they must be evenly distributed around the Earth, with the result that they will from time to time cover regions in which no one lives or the population is very poor. Thus, any margin that can be obtained from these regions will be profit.
“My guess is that they will have different connection prices for different countries, and this will allow them to make the Internet available everywhere, even if it is a very poor region,” Press says. “Once a constellation of satellites is there, then its value is already fixed, and if the satellite is over Cuba and no one is using it, then any income that they can receive from Cuba is marginal and free (no additional investment required)” .
Entering the mass consumer market can be quite difficult. In fact, much of the success that the industry has achieved has come from providing the costly Internet to governments and businesses. But SpaceX and OneWeb, in particular, are targeting regular subscribers in their business plans.
For this market, the user interface will be important, Sachdev said. You must cover the Earth with a system that is easy to use, efficient and economical. “But that alone is not enough,” Sachdev says. “You need enough capacity, and before that you need to ensure affordable prices for client equipment.”
Who is responsible for regulation?
The two big issues that SpaceX had to resolve with the FCC were how the spectrum of existing (and future) satellite communications would be allocated, and how to prevent space debris. The first question is within the FCC's purview, but the second seems more relevant to NASA or the US Department of Defense. Both track orbiting objects to prevent collisions, but neither is a regulatory authority.
"There really isn't a well-coordinated policy on what we should do about space debris," Stanford's Manchester says. "Right now, these people are not communicating effectively with each other, and there is no consistent policy."
The problem is further complicated because LEO satellites pass through many countries. The International Telecommunication Union performs a role similar to the FCC by assigning spectra, but in order to operate within a country, a company must obtain permission from that country. Thus, LEO satellites must be able to change the spectral bands used depending on the country over which they are located.
“Do you really want SpaceX to have a monopoly on connectivity in this region?” Press asks. “It is necessary to regulate their activities, and who has the right to do so? They are supranational. The FCC has no jurisdiction in other countries."
However, this does not render the FCC powerless. Late last year, a small Silicon Valley startup called Swarm Technologies was denied permission to launch four prototype LEO communications satellites, each smaller than a paperback book. The FCC's main objection was that tiny satellites could be too difficult to track and therefore unpredictable and dangerous.
Swarm launched them anyway. A Seattle-based company that provides satellite-to-orbit services sent them to India, where they set off on a rocket carrying dozens of larger satellites, according to IEEE Spectrum. The FCC discovered this and fined the company $900 over 000 years, and now Swarm's bid for four larger satellites is in limbo, the company operating in secret. However, a few days ago there was news that approval had been received and . In general, money and the ability to negotiate — decided. The weight of the satellites is from 310 to 450 grams, there are currently 7 satellites in orbit, and the full network will be deployed in mid-2020. The latest report says that about $25 million has already been invested in the company, which opens up market access not only for global corporations.
For other future satellite Internet companies and existing ones exploring new tricks, the next four to eight years will be critical - they will determine whether there is a demand for their technologies here and now, or we will see history repeating itself with Teledesic and Iridium. But what will happen after? Mars, according to Musk, its goal is to use Starlink to provide revenue for Mars exploration as well as a test.
“We could use the same system to create a network on Mars,” he told his staff. "Mars will also need a global communications system, and there are no fiber optic lines or wires or anything."
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