Visiting researcher assesses Starlink as path to avoid government censorship

Hammas Bin Tanveer, a PhD student in Computer Science at the University of Iowa who has been working as an information controls fellow in the Systems Lab at the University of Michigan, has authored an article summarizing his work in assessing the feasibility of Starlink as a censorship circumvention tool. The article, entitled “Evading censorship from above,” was posted on Medium.

In his paper, Tanveer describes Starlink’s architecture as a Low-Earth Orbit (LEO) satellite constellation composed of more than 4000 satellites with user terminals that are responsible for managing connections between them and over 1400 ground stations that send and receive messages to the constellation.

“Starlink is a private company,” said Tanveer, “so you don’t know anything about the algorithms they use, how they route their traffic, or which satellite you will connect to, since there are a number available at any time and we don’t know how Starlink selects one.” Similarly, we know little about the available bandwidth in areas which face internet shutdowns e.g,. Iran. 

The recent war between Russia and Ukraine led to the destruction of most of Ukraine’s terrestrial internet infrastructure and the Ukrainian government has used Starlink to re-establish internet connectivity for military and civilian use. This connectivity has been noticed by activists supporting free speech in Iran, with the hope of using Starlink in a similar way.

Starlink has activated support for Iran, but the Iranian government, which has imposed a blanket internet censorship regime, has declared the network illegal. This has made Starlink’s use in Iran difficult because Starlink requires that user terminals must be on-site in Iran to enable access to the Starlink satellite constellation. Nonetheless, activists have been able to smuggle some hardware into place to establish a link and circumvent censorship. 

In his article, Tanveer describes how this Starlink infrastructure is able to provide censorship circumvention in Iran with limitations due to inter-satellite links, the availability of satellites over Iran vs. the population of cities in the country to form an overall capacity analysis. He concludes by outlining the steps that Iran is taking to censor Starlink, and possible measures to improve Starlink’s availability in Iran.

Typically, Tanveer notes, Starlink requires a user terminal to reach the satellite constellation, but those satellites must also be able to access a ground station, which provides a link to the rest of the internet.

The fact that there are no ground stations in Iran is currently a good thing for avoiding interception and censorship by the Iranian government, Tanveer says. However, given the number of user terminals currently in Iran and the speed of connections possible, Tanveer estimates that the network will currently support about 150 users at speeds of about 12Mbps. “This is clearly not enough for two major cities with a population of 4.8 million,” he said.