Live coverage: SpaceX to launch 21 communications satellites for the Space Development Agency

Central Coast launch watchers, mark your Thursday afternoon. SpaceX is targeting a 1:32 p.m. PDT liftoff from Space Launch Complex 4 East at Vandenberg Space Force Base, carrying 21 communications satellites for the Space Development Agency's growing military constellation.

According to Spaceflight Now, the mission — designated T1TL-E — represents the third batch of operational satellites launched for the SDA's Proliferated Warfighter Space Architecture (PWSA), a layered low Earth orbit constellation designed to provide secure communications, missile tracking, and navigation for the U.S. military and its allies.

A Midday Liftoff and a Droneshop Landing

For 805 residents, a 1:32 p.m. launch means favorable daytime viewing conditions across the Central Coast. Depending on fog cover — always the wildcard on the Vandenberg coastline — the Falcon 9's exhaust plume should be visible from vantage points in Lompoc, Santa Ynez, and even as far south as Santa Barbara and Ventura counties.

The booster flying this mission, B1103, is making its fourth flight. Spaceflight Now reported that it previously launched Starlink 17-35, Starlink 17-42, and NROL-179. Around 8.5 minutes after liftoff, B1103 will attempt a landing on the droneship "Of Course I Still Love You" stationed in the Pacific. If successful, it would mark the 211th landing on that vessel and SpaceX's 639th booster recovery overall.

Given the daytime launch window and Pacific Ocean touchdown, residents along the coast should not expect the dramatic sonic booms that accompany some Vandenberg landings — this recovery happens hundreds of miles offshore.

Building Out the Transport Layer

The 21 satellites aboard this mission were manufactured by York Space Systems, one of three prime contractors — alongside Lockheed Martin and Northrop Grumman — awarded T1TL construction contracts by the SDA in February 2022.

York has established itself as the pace-setter for Tranche 1 deliveries. Spaceflight Now noted that the company's first production lot of 21 satellites launched on the T1TL-B mission in September 2025, with all spacecraft confirmed healthy within hours of separation. With this second lot, York will have delivered more than 40 spacecraft for the proliferated constellation.

The broader Tranche 1 architecture is ambitious: 154 operational satellites spread across transport, tracking, and missile defense demonstration layers. The transport layer alone calls for 126 satellites, making missions like T1TL-E critical building blocks for a network intended to connect warfighters worldwide.

What This Means for Vandenberg

This launch underscores Vandenberg Space Force Base's continuing role as a primary hub for national security space missions. The T1TL-E mission was awarded to SpaceX under the National Security Space Launch Phase 2 contract, managed by the U.S. Space Force's Space Systems Command.

As the SDA continues building out its constellation — and as SpaceX maintains its steady cadence from SLC-4E — Central Coast residents can expect more daytime and evening launch opportunities in the coming months. The PWSA architecture is nowhere near complete, and future Tranche missions will likely return to Vandenberg given the base's ideal positioning for the orbital trajectories these satellites require.

For Thursday's launch, Spaceflight Now plans to begin live coverage approximately one hour before the 1:32 p.m. liftoff. As always, 805 launch fans should keep an eye on Vandenberg's weather cam and local fog forecasts — that marine layer can turn a spectacular viewing event into a waiting game.

Quick Viewing Notes

• Liftoff time: 1:32 p.m. PDT, Thursday
• Pad: SLC-4E, Vandenberg Space Force Base
• Booster landing: ~8.5 minutes after liftoff on "Of Course I Still Love You" (Pacific Ocean, no audible sonic boom expected onshore)
• Payload: 21 York Space Systems communications satellites for the SDA's Tranche 1 Transport Layer
• Best local viewing: Providence Landing Park, Harris Grade Road, or anywhere with a clear western horizon above the fog