SpaceX successfully tested direct communication between smartphones and Starlink satellites

American rocket launch company and the operator of the biggest satellite constellation, SpaceX, has made progress in launching and testing its new variant of Starlink satellites with so-called direct-to-cell capability.

The technology allows currently marketed smartphones to communicate directly with the satellites, therefore completely bypassing the need for a Starlink user terminal (SpaceX’s proprietary antenna and router), as well as the need for mobile network coverage in the area.

SpaceX had narrowly missed the original plans to conduct the first testing of the feature in 2023, as the first direct-to-cell Starlink satellites launched to orbit on January 2, 2024.

Just six days afterward, SpaceX performed the first successful testing of the Earth-to-orbit-and-back communication between two LTE smartphones using the T-Mobile frequency spectrum, the company said on Wednesday.

SpaceX’s Falcon 9 workhorse rocket lifted an additional 21 Starlink satellites in early January, six of which were equipped with the direct-to-cell technology. The key appeal of SpaceX’s solution is the support of currently marketed LTE smartphones. There is no need for phone manufacturers to adopt new technology or for users to buy a new smartphone.

But the ability to connect cell phones to satellites comes with several challenges, as the company explains:

“For example, in terrestrial networks cell towers are stationary, but in a satellite network they move at tens of thousands of miles per hour relative to users on Earth. This requires seamless handoffs between satellites and accommodations for factors like Doppler shift and timing delays that challenge phone to space communications. Cell phones are also incredibly difficult to connect to satellites hundreds of kilometers away given a mobile phone’s low antenna gain and transmit power.”

According to SpaceX, direct-to-cell Starlink satellites are addressing these challenges with innovative new custom silicon, phased array antennas, and advanced software algorithms.

Currently, the plan is to launch hundreds of direct-to-cell Starlink satellites to enable text service in 2024, with voice, data, and Internet of Things (IoT) services coming in 2025.

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