SpaceX is preparing to launch 21 York Space Systems-built satellites for the Space Development Agency's Tranche 1 Transport Layer E (T1TL-E) mission aboard a Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base on Thursday. Liftoff is scheduled for 1:32 p.m. PDT (2032 UTC).
Third batch of a proliferated LEO mesh
The Proliferated Warfighter Space Architecture (PWSA) — SDA's constellation of interconnected LEO satellites — will eventually field 154 Tranche 1 spacecraft: 126 in the Transport Layer, 28 in the Tracking Layer and four missile-defense demonstrators. Data will be managed from Space Operations Centers at Grand Forks Air Force Base and Redstone Arsenal. Today's launch is the third T1TL batch to fly since T1TL-B in September 2025.
York first among Tranche 1 primes
Denver-based York Space Systems has now completed and shipped its second production lot of Tranche 1 spacecraft, becoming the first of the three T1TL primes to do so; Lockheed Martin Space and Northrop Grumman Strategic Space Systems are also under contract from a February 2022 SDA award. Northrop's satellites have yet to launch.
Booster B1103 flies again
SpaceX will use first-stage booster B1103 on its fourth flight — following Starlink 17-35, Starlink 17-42 and NROL-179 — and target a droneship landing on "Of Course I Still Love You" in the Pacific about 8.5 minutes after liftoff. If successful, it will be SpaceX's 639th booster recovery. Related: SpaceX targets Starship Flight 13 and Besxar Fabships on Falcon 9.
Reporting based on coverage from Spaceflight Now and Space Development Agency press materials.