One of SpaceX’s most ambitious projects remains on the ground, for now

A stack of 60 SpaceX Starlink satellites floats in orbit above Earth.

Source: SpaceX

To finance its Martian ambitions, SpaceX intends to transform Earth, covering the planet with ubiquitous Internet coverage transmitted from a tight mesh of thousands of satellites. CEO Elon Musk hopes that this “Starlink” service will eventually generate $ 30 billion per year.

In space, construction proceeds smoothly. SpaceX has already become the world’s largest satellite operator, managing more than 500 satellites and counting. That’s a fraction of the thousands it intends to launch, but enough for the system to reach the Air Force booths and connect Musk to Twitter. The company intends to start beta testing in North America this summer.

On the ground, however, SpaceX still has work to do. It has yet to reveal hardware to connect a customer’s home to the satellites flying overhead. The company will also need a network of ground stations that link its satellites to the Internet’s physical backbone. Building these nodes is not rocket science: In fact, 26 are already planned for the US But without a crucial satellite upgrade, those stations will keep the coverage of the network largely glued to the ground.

“Initially it is not a global service,” says Tim Farrar, president of TMF Associates, a telecommunications and satellite research firm, “even though satellites fly all over the place.”

Global broadband transmission

Efforts to transmit data from the heavens have generally been divided into two categories: very close and far away. Google’s parent company Alphabet is deploying internet balloons about 12 miles off the ground in Kenya, for example, and Facebook is on the lookout for solar powered drones. These near-surface approaches are fast, but each floating antenna has a limited geographic footprint.

In contrast, companies like Canadian communications firm Telesat have long operated handfuls of satellites in high orbits more than 20,000 miles above Earth’s surface, where each machine can reach a wide swath of the planet. These systems offer global coverage, but snail-type connections, with round-trip signals that take more than half a second. “That doesn’t seem like a big deal, but a typical website could have 100 round trips,” says Telesat vice president Erwin Hudson. “Adds”.

With Starlink, SpaceX joins a number of companies, including Telesat, all competing to offer the best of both worlds: satellite “constellations” close enough to communicate with the ground in tens of milliseconds, but far enough away to cover the planet at a reasonable price. Number of satellites. However, to complete the service, SpaceX needs two more pieces of ground infrastructure.

Starlink’s biggest land obstacle

Starlink’s main land obstacle, Musk acknowledges, is the antenna that will put users online: the Internet analogue of the TV parabolic dish. Starlink’s low-flying satellites cross the sky in about five minutes, and the antennas will need to be kept up to date. SpaceX’s design has to balance technological sophistication with mass market affordability.

The company plans to use “phased array antennas,” which can direct the machine’s focus electronically rather than physically rotate it. The technique simplifies the device mechanically, but it comes at a high price. Farrar estimates the device could cost more than $ 1,000, though Musk is aiming for a price under $ 300. In March, the FCC authorized SpaceX to distribute one million antennas, and SpaceX board members recently tested the devices (which reportedly resemble “UFOs on a stick”), but the company has yet to announce the commercial version.

Any satellite service also needs a network of ground stations to take advantage of the existing fiber optic infrastructure. These are the points where the space network merges with the world network. “What goes up must come down,” said Hudson.

SpaceX is also preparing these “gateway” stations. The company has registered 26 locations with the FCC, each of which can house eight antennas. Some are owned by SpaceX, while others belong to telecommunications companies, such as Level Three Communications, which can presumably supply high-speed connections. Handfuls of mushroom-shaped domes (transparent weather protection for antenna radars) have recently appeared in some of the lots.

Why is crosslinking the key concept?

These front doors are just the beginning. To get the most out of it, Starlink will eventually need thousands of gateway antennas (roughly one via satellite) spread across hundreds of sites around the world, according to Íñigo del Portillo Barrios, a recent MIT graduate who has analyzed the structure of the Starlink and Telesat constellations.

He says Starlink relies heavily on these stations because the current batch of satellites lacks a feature originally planned for the machines to communicate with their neighbors via laser. This “cross-linking” capability would allow Starlink to pass a signal to any user under any satellite, including those in the air, on remote islands, or in conflict zones. But without it, a satellite must be able to link a user to a gateway antenna directly, limiting coverage to approximately 500 miles from each ground station, Farrar estimates.

“They will have big holes in the middle of the oceans and some deserts,” said Farrar. “They will have to go to a country’s regulator and say, ‘please let us in, let us build the gateways in your country.'”

That is not a great success in reaching most rural areas (currently planned stations will cover most of the United States and Mexico). But traditional satellite Internet customers, such as the military, who might want access to central Iraq, for example, or airlines and shipping companies looking for connectivity in the Atlantic and Pacific, may prefer to expect truly global service.

SpaceX did not respond to a request for comment on its gateway or cross-linking plans, but Hudson says that despite Telesat having 50 years of satellite experience and planning to start launching cross-link-enabled satellites in 2022, the choreography operations terrestrial will continue to represent one of their greatest challenges.

“We are building earth stations on all continents, except possibly Antarctica,” he said. “You have to send things everywhere. You have to build, maintain and upgrade them.”

Adding cross links will eventually help SpaceX lessen the influence of geography on Starlink’s coverage, and the company intends to start experimenting with interconnected satellites sometime this year, President Gwynne Shotwell said.

But the upgrade will not be simple, and the second generation network will not be operational in the immediate future. First SpaceX needs to overhaul its satellite design to incorporate a more robust power supply, finely tuned lasers, and other hardware. Then you will also have to rebuild and relaunch the entire swarm.

The company can do it eventually, Farrar said, but first Starlink will have to prove its worth with the satellites it has in the sky and the entry stations it can build on the ground.