Explained: Iran's 'Kill Switch' Strategy To Jam Starlink Internet

The jamming of Elon Musk's Starlink satellite internet used by some Iranian opposition members has led to an information blackout in the crisis-hit nation, where a protest against soaring inflation and economic hardship two weeks ago escalated into violent clashes. More than 500 protests have taken place across all of Iran's 31 provinces. The number of dead reached at least 648.

Tehran has sought to completely cut off internet access as the protests intensify, in a strategy known as a 'kill switch' approach. Nations across the world use it in a localised context to prevent spread of misinformation during a crisis.

A blackout of the internet delivered by ground cables to PCs and mobile phone masts lasted over three-and-a-half days. The big move, however, is Iran is working to block access to Starlink satellite internet service.

But how exactly is Iran jamming Starlink internet service?

The satellite provider -- owned by Elon Musk's rocket company SpaceX -- has been one way for people to get around Tehran's centralised, fine-grained control over internet access.

But its service can be disrupted relatively efficiently by interfering with GPS signals, as base stations need to share their position with the satellite network so it can identify the nearest ground station. GPS is short for global positioning system.

An alternative method - blocking transmissions between the satellite and the ground terminal - would require a very large number of jamming devices, Bryan Clark, an electronic warfare expert at the Hudson Institute Washington think tank, told news agency AFP.

Jamming Equipment

Jamming equipment designed to target mobile phones is sold commercially and could be adapted to target Starlink systems with the right technical know-how, he said.

Starlink's "constellation" of telecom satellites circle in a low-Earth orbit (LEO) around 550 km from the ground. Much like a mobile phone connecting to different base stations as a user moves around, Starlink terminals must constantly hand off from one satellite to another as they pass overhead.

This feature - unlike more traditional telecom satellites in geostationary orbit over one spot on the Earth's surface - means Starlink satellites and terminals must have an antenna that accepts signals from a wider angle, which leaves it vulnerable to jamming from somewhere close to the antenna on the ground.

The need to place jammers close to the receiver on the ground has, however, hampered the efforts of Russian forces in Ukraine, where Kyiv's troops are still using Starlink despite intense jamming.

Given the tight cooperation between Tehran and Moscow, including on missiles and drones for the Ukraine invasion, Iran may have received jamming equipment and most importantly know-how from Russia, AFP reported quoting an unnamed source.

Starlink is also operating in a grey zone of legality with respect to its terminals in Iran, which has complained to the International Telecommunication Union (ITU) about Starlink providing satellite internet service on its territory.

With inputs from AFP