SpaceX recently revised the likely roadmap for its Starlink initiative, a plan to beam high-speed internet across the globe using a satellite constellation. The changes slightly reduced the number of satellites that will need to launch, where they’ll be positioned, and how they’ll interact.
The company has permission from the Federal Communications Commission to put 4,425 satellites into orbit and has a long-term plan of launching almost 12,000. But how exactly will this work?
To try and make this ambitious plan more accessible, Mark Handley, a professor of networked systems at University College London, created a visualization of how the first phase of the Starlink array would operate. He tells Inverse that it would enable connection between London and Singapore in about half the time that is possible with the current fiber optic infrastructure.
“Partly that’s because the speed of light in a vacuum is roughly 50 percent more than in glass, and partly it’s because the existing fiber doesn’t take the most direct path, due to geopolitical issues in the Middle East,” he explained.
So how, exactly, does Space’s new application to the FCC serve these ends? The company is now proposing that a portion of the Starlink satellites destined for orbit be placed at 550 kilometers above the Earth’s surface, instead of the initially proposed 1,150 km. Handley highlights three significant implications of these tweaks, which he says both improve Starlink’s efficiency and the likelihood that it’ll be available by 2020.
1. Fewer Satellites in Total
To start, there will be exactly 16 fewer satellites floating above our heads. Starlink’s first phase was slated to consist of 1,600 orbiters, meaning we’re now looking at a total of 1,584 after accounting for the revisions.
This might seem minor but the FCC was concerned about the sheer amount of stuff SpaceX planned on launching into orbit when Starlink was first proposed, any decrease in Starlink’s footprint will likely bode well with the government agency.
Perhaps more significantly, it would also drastically reduce the amount of space junk that Starlink would wind up contributing over all. At their previous height, once defunct, Starlink’s satellites could wind up circling the globe for hundreds of years before falling down to earth. The new height reduces this time frame to around five years.
SpaceX's new proposal should reduce the chances of Starlink satellites colliding.
2. Less Chance of Collision
Starlink satellites will move constantly, with all of this criss-crossing creating a likely chance of collisions. But fewer moving pieces mean fewer things can go wrong.
Originally, the satellites would get as close as 40 km away from each other, which is a little more than a half-marathon away. That’s “fairly close” for orbital standards, according to Handley. Now with the new proposal, that’s increased to 90 km to reduce the chances of something going amiss.
3. Biased Towards East-West Connection
In the video, Handley assumes that the new proposal will make it so each satellite is linked to four other nearby orbiters. Initially, the spacecraft were supposed to link with five others, but Handley notes that it’s not entirely clear if this means they will be limited to four.
The new proposal suggests each satellite will only connect to four nearby orbiters instead of five.
Satellites will use lasers communication to beam information to one another. This communication setup creates routes that are excellent for slingshotting connectivity east and west but suffer slightly with north and south paths.
“Where the lack of that fifth laser starts to hurt is with north-south paths,” explains Handley. “If you want to go from, say London to Johannesburg, you’re often going to end up with a dogleg path like.”
No fifth laser, means there are fewer paths to get information where it needs to be. SpaceX has opted for a safer game-plan for slightly less ambitious results. But even with these slight changes, Starlink still seems on track to revolutionize internet speeds.
