Speaking at Tesla’s annual shareholder meeting, CEO Elon Musk – also CEO of SpaceX – briefly segued to his spaceflight company’s ambitious Starlink program and discussed how he believes the satellite constellation can support no more than 3-5% of the global population.
On May 23rd, SpaceX successfully launched 60 “v0.9” Starlink satellites – weighing as much as 18.5 tons (~41,000 lb) – into LEO, a first step unmatched in ambition in the history of commercial satellites. Delivered to an orbit of ~450 km (280 mi), all but four of the 60 spacecraft have managed to successfully power up their electric ion thrusters and 55 have already raised their orbits to ~500 km (310 mi). For what is effectively a technology/partial-prototype demonstration mission, the record of Starlink v0.9 performance is extremely impressive and bodes well for a quick and relatively easy design optimization (to “v1.0”) before true mass production can begin.
In general, Musk was more than willing to acknowledge some of the potential limitations of a Low Earth Orbit (LEO) broadband satellite constellation at Tesla’s 2019 shareholder meeting. Most notably, he bluntly noted that Starlink is not designed to service densely populated areas and will predominately be focused on low to medium-density populaces. Triggered by an investor’s question about the possibility of integrating Starlink into future Tesla cars, Musk reiterated that SpaceX’s first-generation Starlink user terminals (i.e. ground antennas) will be roughly the size of a “medium pizza”.
Although pizza sizing is not exactly ISO-certified, Starlink’s user antennas will presumably be around 12-14 inches (30-36 cm) wide and come in a square form factor. Thanks to the use of what Musk believes are the most advanced phased array antennas in the world, neither the antennas on Starlink satellites or user terminals will need to physically move to maintain a strong signal. Still, as Musk notes, an antenna the size of medium pizza box would still stick out like a sore thumb on the typically all-glass roof of an of Tesla’s consumer cars, although built-in Starlink antennas might actually make sense on Tesla Semis.
Elon Musk’s specific comment indicated that Starlink – at least in its current iteration – was never meant to serve more than “3-5%” of Earth (population: ~7.8 billion), with most or all of its users nominally located in areas with low to medium population densities. This generally confirms technical suspicions that Starlink (and other constellations like OneWeb and Telesat) is not really capable of providing internet to everyone per se.
For SpaceX, each Starlink satellite – per official statements that the first 60 satellites represent more than 1 terabit of bandwidth – likely offers bandwidth of roughly 17-20 gigabits per second. In simpler terms, this means that one Starlink satellite overhead could theoretically support as many as 4000 users simultaneously streaming YouTube videos at 1080p/30fps, a figure that sounds impressive but glosses over the sheer number of people that live in cities. Importantly, every single Starlink satellite at ~550 km will likely have a service radius of several thousand – if not tens of thousands of – square kilometers.
Even though the US is exceptionally large and spread out relative to most other countries, a single square kilometer of New York City, Los Angeles, San Francisco, Boston, Miami, Seattle, or dozens of other cities could effortlessly saturate a Starlink satellite’s bandwidth. Even the smallest of towns and cities could easily use most or all of ~20 Gbps at peak hours. In short, Starlink is going to be extremely bandwidth-constrained. Even if SpaceX can double or triple each satellite’s bandwidth and have 10-100 satellites overhead and capable of delivering internet at any given moment, it’s hard to imagine that Starlink will ever be able to serve every person that falls under its coverage area.
Additionally, this means that there is a strong chance that Starlink internet customers will be subject to relatively strict bandwidth limitations and throttling at peak hours. Thankfully, these limitations will be made entirely out of technical necessity, standing in stark contrast to the arbitrary, greed-motivated carriers and ISPs Americans are almost universally accustomed to. In an absolute worst-case scenario, Starlink’s already-connected US customers would get roughly the same quality of service they are used to at roughly the same price. However, they would be able to rest assured that their money was going to SpaceX instead of filling the pockets of the robber-baron-esque shareholders and executives that run American ISPs.
Ultimately, the estimates provided above are exceptionally conservative and generally assume worst-case scenarios. SpaceX could very well beat expectations and develop unique and innovative ways of efficiently using its available bandwidth, while also tirelessly working to improve its technology and expand the carrying capacity of newer satellites. In general, CEO Elon Musk’s comments serve as an excellent temper to the hype surrounding Starlink. SpaceX isn’t going to initially be breaking the backs of Comcast or Time Warner but there’s no reason to believe that that day will never come.
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