I’m just curious what the bottlenecks are and what has been done to improve those. Because I remember when it would take 10 seconds to send an imessage and now I can watch YouTube when my connection is solid. Just impressive and I’m curious about it.
In: Technology
There are two kinds of relevant speeds here:
– Latency is how long it takes for an action you make to reach a server on the Internet, and for a small response to make it back to you.
– Throughput is the amount of information-per-second that can be transmitted.
Latency is extremely important for tasks like browsing the web or using Google Docs. Throughput is extremely important for streaming video.
Throughput has improved by launching more satellites and by improving the radio technology. Latency to satellites can only be improved by having satellites in a lower orbit. Satellites are far enough away that it takes the radio waves (which move at light speed) a noticeable amount of time to go back and forth, and those in a higher orbit have significantly higher latency.
When flying over land, many in-flight WiFi now use ground-to-air instead of satellites. The Internet provider built a large number of towers, similar to cell phone towers, with antennas pointed at the sky. These style of networks have much better latency, but only over land (they can’t build towers in the middle of the ocean).
If you take an international flight over a large ocean, latency may still be problematic though the throughput may be good.
It’s not so much about technological improvements (though of course there’s always those) so much as an investment. Planes use satellite feeds to enable internet and that shit’s expensive, both installation and bandwidth rental
But some airlines (jetblue in particular) made that investment, thinking their customers would see available internet on their flights as a valuable perk over their competitors and..they were right.
So over the years other airlines have made that investment to add and improve their service. There hasn’t been substantial and major breakthroughs technology-wise in the last few years. Mostly just airlines competing with each other realizing that if you’re going to be stuck in a box for several hours, having some connection to the outside world is a valuable feature for their customers, and no one airline wants to be the one with no, or worse, internet.
It’s literally one company, called Viasat, located in San Diego.
While there are tech improvements, but the satellite and ground station infrastructure didn’t exist in any good way until Viasat, well, built them. basically most of the aircraft WiFi used ground towers (not satellites) and the few internet satellites were old and didn’t have much bandwidth and bad latency and had to use a complex combination of back and forth between towers like the tower based versions creating a mayhem of patchwork to get it to work at all.
Viasat decided to enter the aircraft market and sent up some expensive, brand new sexy satellites that would have been too complex and expensive before, that basically solved all the problem allowing the planes to directly connect to the satellite and the satellite with a high speed connection to a ground station
Literally one company. In San Diego. That’s it. There weren’t really big tech improvements, there were improvements, but literally everything else was a crazy patchwork, until Viasat setup a dedicated system.
Well the main thing isn’t about the radio link, it’s about the amount of satellites.
Those things used to be insanely expensive to launch, maybe you launch half a dozen of them per rocket and it’s an expensive rocket. To enable global coverage with very limited amount of satellites, you need to launch them very high in the orbit and each satellite needs to cover a huge area. This increases latency and reduces the available radio resources assigned to each user.
With SpaceX’s launch solutions, you can drop hundreds of them into the sky cheaply and easily. With more than enough satellites, each only has to cover a small area, so they can fly in very low orbits, this also helps improving radio performance.
In addition to the other reasons given by others, the connection hasn’t always been satellite either. Some of the earlier connections were actually over a cellular link. So imagine all the passengers on the plane sharing the same cell phone data connection.
Oh, I love questions like these, because my job is technical strategy and engineering for inflight WiFi at an airline! (And before that I did WiFi for cruise ships)
First and foremost, satellite connectivity on a flight is exceedingly complicated – you have to send a radio beam about a 1° wide from an airplane moving at 800km/h up to a target about 2-3m across on a satellite that is 35,000 km away in geosynchronous orbit and is itself moving at 18,000 km/h. The satellite beam coming back is much wider and typically covers several hundred km across. (And this gets very different when dealing with a low-orbit platform like Starlink… more on that in a minute). I do this for a living and I’m still amazed every day that any of this actually works at all.
That satellite beam has the ability to deliver about 100Mbps (on Ku-band) or 200Mbps (on Ka-band), but it’s usually shared between multiple airplanes.
So what’s changed in the last 5-10 years? Simply put, demand. There are a lot of more people that want to use the internet in flight, and so the beams have to be shared between fewer and fewer airplanes. Which means you need a LOT more beams up there. Older satellites can support about 50 beams. Newer smaller ones can support a few hundred, and 2023 saw the launch of two satellites the size of a bus that had several *thousand* beams. One of them failed when it reached its assigned orbital station, and its owner was able to salvage about 10% of its capacity, which is still several hundred more beams.
my airline has about 3/4 of our fleet of over 800 airplanes in the air over North America at any given time. Each of those airplanes has 150-170 passengers on board, many of whom use the internet, for about 4000 flights a day (and that’s just us, there are almost 10x that many airplanes up there with us!)
Each one of those thousands of flights transfers several gigabytes of data. Often it will switch from one satellite to another during the flight. The antenna in the hump on the roof dutifully tracks where it needs to point, through aircraft maneuvers and turbulence.
putting stuff in orbit is *obscenely* expensive, especially big stuff. But in the last decade or so, the cost to put stuff in space has dropped significantly because SpaceX figured out a way to launch rockets faster and cheaper. And so a lot of satellites have been launched in the last decade.
SpaceX also figured out that if they were gonna be yeeting rockets into space anyway, that instead of using water, or potatoes, or Justin Bieber albums for weight, they could manufacture a whole bunch of tiny satellites that flew around at about 550km above the earth instead of 35000km, that they could use to deliver internet a lot faster… because it takes a radio wave moving at the speed of light almost an entire second to go up 35000km to space and back down again to get to the internet. When your satellite (which is basically just a really fancy WiFi router) is only 550km away, that signal gets there and back in a few milliseconds. The caveat is that when the satellite is that low, it’s orbiting the entire planet once every 90 minutes or so, which means you’ve gotta hit a moving target. Easy for an airplane to do, though.
The catch is that in order to install all that fancy gear on an airplane, a whole lot of engineering and testing has to happen to make sure the changes to the airplane don’t compromise its ability to fly. This process takes *years* to get a given system certified on a particular airplane.
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