SpaceX sent and received its first text messages sent via T-Mobile using its D2D (direct-to-device) Starlink satellites launched just over a week ago, the company announced. First revealed in August 2022, the project aims to provide satellite internet connectivity to regular cell phones so that T-Mobile customers can stay online even when they’re in a terrestrial dead zone.
T-Mobile said that it aims to publicly launch text services with T-Mobile in 2024, with voice, data and IoT (internet of things) plans coming in 2025. Globally, SpaceX has partnered with Rogers in Canada, Australia’s Optus, KDDI in Japan and others.
The scheme requires larger, special versions of the Starlink satellites with D2D capability. SpaceX launched the first six of those on January 2, completing early tests with no issues. “On Monday, January 8, less than 6 days after launch, we sent and received our first text messages to and from unmodified cell phones on the ground to our new satellites in space using TMobile network spectrum… [indicating that] the system works,” SpaceX wrote in a blog post.
When the plan was announced, T-Mobile CEO Mike Sievert said the technology is like putting a cellular tower in the sky. He added that it could one day eliminate dead zones, allowing people to easily get in touch with loved ones even if they’re in the middle of the ocean.
SpaceX said that the system, which uses LTE/4G (not 5G protocols) is a bit more complicated than cell towers in the sky, though. Since the satellites move at tens of thousands of miles per hour relative to the Earth, data must be handed off seamlessly between them. Doppler shift, timing delays and the relatively low transmission power of smartphones must also be accounted for.
The two companies aren’t the first to test such a system. Working with communications specialist AST SpaceMobile, AT&T successfully conducted the first two-way satellite audio call on its network in April, calling a number in Japan with a stock Samsung Galaxy S22 smartphone. AT&T also complained to the FCC that SpaceX and T-Mobile’s plan was “woefully insufficient” regarding the risk of harmful interference to ground-based networks.
This article originally appeared on Engadget at https://www.engadget.com/spacex-and-t-mobile-send-the-first-text-messages-from-orbiting-starlink-satellites-103526219.html?src=rss