11.09.2025

The "Tranche 1 Transport Layer" network will eventually consists of 126 satellites in low Earth orbit.

SpaceX sent 21 satellites to orbit from California today (Sept. 10), beginning the buildout of an advanced new constellation for the U.S. military.

A Falcon 9 rocket launched from Vandenberg Space Force Base today at 10:12 a.m. EDT (1412 GMT; 7:12 a.m. local California time), kicking off the Space Development Agency's (SDA) first "Tranche 1 Transport Layer" (T1TL) mission.

The T1TL network will eventually consist of 126 satellites in low Earth orbit (LEO), which "will provide global communications access and deliver persistent regional encrypted connectivity in support of warfighter missions around the globe," according to an SDA explainer.

The SDA was established in March 2019, tasked with helping the U.S. military field highly capable and cost-effective space assets on rapid timelines.

"Recognized as the Department of Defense's constructive disruptor for space acquisition, the Space Development Agency (SDA) will quickly deliver needed space-based capabilities to the joint warfighter to support terrestrial missions through development, fielding, and operation of the Proliferated Warfighter Space Architecture," the SDA's website reads.

The Proliferated Warfighter Space Architecture (PWSA) is an envisioned LEO constellation of hundreds of small satellites, which will be linked via optical communications. This constellation will consist of seven "layers" — battle management, custody, deterrence, navigation, (missile) tracking, transport and support.

If all goes to plan, the PWSA will be refreshed and updated every two years, via the launch of a new "tranche" of satellites.

Quelle: SC