The transport layer in the Space Development Agency’s National Defense Space Architecture (NDSA). Photo: SDA

The U.S. Space Force’s Space Development Agency (SDA) issued a solicitation this week for one contractor to build about 20 Tranche 2, Transport Layer (T2TL)-Gamma satellites, the final in the T2TL series.

The T2TL Alpha and Beta satellites, which are to begin launches in September 2026, are to have three optical communications terminals (OCTs), and the Gamma satellites are to add a fourth OCT and a classified “Warlock” mission payload. The T2TL-Gamma satellites are to launch by June 1, 2027.

“Every T2TL-Gamma SV [space vehicle] will be interoperable with all PWSA Transport Layer SVs, regardless of vendor,” SDA’s Gamma solicitation said. “The T2TL-Gamma SVs will include OCTs to support in-plane and cross-plane links, links to terrestrial OCTs (ground, air, and maritime), and links to compatible SVs external to the Transport Layer. The T2TL SVs, in conjunction with the SDA OCs and the T1TL SVs, will form a communications network that will provide resilient, low-latency, high throughput data transfer to and from any location on the globe.”

The earlier T2TL-Alpha satellites are to transmit beyond line-of-sight Link 16 data to military forces from space, while T2TL-Beta satellites are to transmit over Ultra High Frequency S-band for tactical satellite communications.

This story was first published by Defense Daily