One of the most interesting wireless networks right now is Starlink from Elon Musk’s SpaceX. People have talked about deploying satellite-based Internet service for almost as long as the Internet has existed. Dozens of companies have tried and either failed or greatly scaled back their ambitions. But Starlink looks to be succeeding rather spectacularly. Past attempts at these systems have foundered on the very difficult physics of offering broadband from a few hundred miles up, leading to systems that have only modest capacity. Yet Starlink seems to be offering competitive bandwidth rates to a large audience. We have tried many times over the years to understand how much capacity Starlink actually offers, not just per unit, but for the entire system. This has been a sticking point in the past, and we were never able to figure out just how much Starlink was capable of. But now we have what looks like a very credible analysis of their capacity, with just one small problem…the source making the rounds online is a report from China’s military intelligence apparatus.
The document in question first appeared here, the reputable David Cowhig’s Translation Blog. It contains a translation of “The Development Status of Starlink and Its Countermeasures.” So right from the start we know the goal of the authors. (Download a copy before it gets deleted from the Internet.) The authors are faculty at the Beijing Institute of Tracking and Telecommunications Technology and the Beijing Institute of Radiation and Measurement Technology. We should state now that we cannot vouch for the veracity of this paper, the authors or even the institutions they work for. There is enough corroboration online for us to think it is credible, but the fact that we cannot find much evidence of these institutions should be a taken as a healthy dose of salt.
That being said, the data contained in this report is fascinating. First, the majority of the paper’s bibliography comes from what appear to be other Chinese academic sources, with nothing from the company itself. It should be clear that Starlink has been of interest to China for some time. And while Starlink’s very prominent role in the war in the Ukraine makes this paper especially timely, the war itself is not the impetus for the paper.
The next bit that stood out for us was the sheer scope of Starlink’s ambitions. Starlink now has around 1,700 satellites in orbit, with plans to grow those to 42,000 over time. That is a huge number and an incredible ambition. We noted above that many people have tried to do this in the past, none have gotten anywhere near this scale. Past attempts found that they could not put up enough vehicles to build sufficient capacity, while at the same time, ground based cellular systems grew exponentially and came down the cost curve very quickly. For most users, cellular services were much cheaper, and only companies operating in remote areas (mining operations, aid organizations, offshore oil fields, etc.) needed the global range the satellites provided. Arguably, Starlink blew past that constraint by putting up enough low-cost satellites, quickly enough to achieve scale.
Which leads to the question of bandwidth. The paper claims that each satellite has 17-23 Gb/s of capacity, with each user getting about 50mbps. This implies each satellite can handle about 400 simultaneous users. By contrast, 5G cellular systems deliver about the same data rates, but modern base stations can handle somewhere closer to 1,000 simultaneous users. An apples to apples comparison is tricky, but the point is that Starlink has sufficient capacity to be commercially viable. And the authors point out that the company has plans to greatly expand capacity on future vehicles. By this math, Starlink will never be able to entirely replace cellular, but that is not really the goal, and the system will eventually have sufficient capacity to be a major player in broadband, everywhere.
The rest of the paper focuses on military uses of Starlink, and remember this paper was likely prepared prior to the war in Ukraine. The authors believe Starlink can provide more than battlefield communications, it can also be used to detect targets and provider reconnaissance – which we have heard rumors about recently.
Finally, we should note that the authors’ goals of exploring countermeasures do not really deliver. Judging from the paper, they do not have any clear way to track, let alone block Starlink satellites today. Their list of countermeasures read as more of a wish list than a plan of attack, which should provide Mr. Musk some comfort for the moment.
We have always been somewhat skeptical of widespread satellite communications systems moving beyond specialized markets to a broader consumer offering. Remember all that speculation that Apple was going to add satellite features to future iPhones? When we wrote about this, we came to the conclusion that all the iPhone would be able to do was use satellite links for emergency text messaging. So we have to admit that if this information is accurate (and it may not be) then Starlink has greatly expanded the realm of the possible for consumer satellite communications.