SDA Tranche 1 Transport Layer A
Falcon 9 Block 5
SpaceX
Rocket Launch Video
SpaceX: SDA’s Fourth Tranche 1 MissionRocket Launch Timeline
Enhance your rocket launch experience with a detailed timeline! From pre-launch preparations to post-launch milestones, a well-structured schedule ensures every step—payload prep, safety checks, and liftoff—runs smoothly. Stay informed and follow the action with precision.
| T- 00 : 38 : 00 | GO for Prop Load Launch director verifies go for propellant load |
| T- 00 : 35 : 00 | Prop Load Start of propelland loading |
| T- 00 : 35 : 00 | Stage 1 LOX Load Start of liquid oxygen loading in the first stage |
| T- 00 : 16 : 00 | Stage 2 LOX Load Start of liquid oxygen loading in the second stage |
| T- 00 : 07 : 00 | Engine Chill Start of engine chilling |
| T- 00 : 01 : 00 | Tank Press Fuel tanks are pressurized to flight levels |
| T- 00 : 01 : 00 | Startup The onboard computer takes control over the countdown and runs last checks |
| T- 00 : 00 : 45 | GO for Launch Launch director verifies go for launch |
| T- 00 : 00 : 03 | Ignition Start of the engine ignition sequence |
| T+ 00 : 00 : 00 | Liftoff First upwards movement of the rocket |
| T+ 00 : 01 : 04 | Max-Q Maximum dynamic pressure |
| T+ 00 : 02 : 14 | MECO Cut-off of the main engine |
| T+ 00 : 02 : 18 | Stage 2 Separation Separation of the second stage from the first |
| T+ 00 : 02 : 25 | SES-1 First start of the second engine |
| T+ 00 : 02 : 31 | Booster Boostback Burn Startup Start of the booster boostback burn |
| T+ 00 : 03 : 04 | Fairing Separation Separation of the payload fairing |
| T+ 00 : 03 : 24 | Booster Boostback Burn Shutdown End of the booster boostback burn |
| T+ 00 : 06 : 09 | Entry Burn Startup Start of the atmospheric entry burn |
| T+ 00 : 06 : 21 | Entry Burn Shutdown End of the atmospheric entry burn |
| T+ 00 : 07 : 15 | Stage 1 Landing Burn Start of the first stage landing burn |
| T+ 00 : 07 : 19 | Stage 1 Landing Landing of the first stage |
Mission
SDA Tranche 1 Transport Layer A
- Type: Government/Top Secret
- Orbit: Polar Orbit
- Launch Cost: $52,000,000
Tranche 1 Transport Layer A is one of six missions by the United States Space Force Space Development Agency (SDA) for the Proliferated Warfighter Space Architecture (PWSA) Tranche 1 Transport Layer constellation, which will provide assured, resilient, low-latency military data and connectivity worldwide to the full range of warfighter platforms from Low Earth Orbit satellites.
The constellation will be interconnected with Optical Inter-Satellite Links (OISLs) which have significantly increased performance over existing radio frequency crosslinks. It is expected to operate over Ka band, have stereo coverage and be dynamically networked for simpler hand-offs, greater bandwidth and fault tolerance.
This launch carries 21 satellites manufactured by Northrop Grumman.
Location
Space Launch Complex 4E
Vandenberg SFB, CA, USA
Find the best place to watch the launch from Vandenberg
Space Launch Complex 4E has witnessed the launch of 299 rockets, including 299 orbital launch attempts. While Vandenberg SFB, CA, USA, has been the site for 915 rocket launches.
Vandenberg Space Force Base is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the Western Range, and also performs missile testing. The United States Space Force's Space Launch Delta 30 serves as the host delta for the base, equivalent to an Air Force air base wing. In addition to its military space launch mission, Vandenberg Space Force Base also hosts space launches for civil and commercial space entities, such as NASA and SpaceX.
Rocket
SpaceX Falcon 9 Block 5
Falcon 9 is a two-stage rocket designed and manufactured by SpaceX for the reliable and safe transport of satellites and the Dragon spacecraft into orbit. The Block 5 variant is the fifth major interval aimed at improving upon the ability for rapid reusability.
Landing
Core B1103
The Falcon 9 first stage B1103 will land on Landing Zone 4 after its 6th flight. Booster B1103 last launched 08/12/2026 and has seen 5 successful launches and landings. Falcon 9 booster.
A sonic boom is likely to occur a few minutes after launch as the booster returns to the launch site. Be prepared for a loud but thrilling experience! Learn more about rocket launch sonic booms
Landing Zone 4 - LZ-4
LZ at Vandenberg
Return to Launch Site - RTLS
A return to launch site usually means that after stage separation the booster flips and does a burn back towards the launch site, landing near where it initially launched from.
Agency
SpaceX
Space Exploration Technologies Corp., known as SpaceX, is an American aerospace manufacturer and space transport services company headquartered in Hawthorne, California. It was founded in 2002 by entrepreneur Elon Musk with the goal of reducing space transportation costs and enabling the colonization of Mars. SpaceX operates from many pads, on the East Coast of the US they operate from SLC-40 at Cape Canaveral Space Force Station and historic LC-39A at Kennedy Space Center. They also operate from SLC-4E at Vandenberg Space Force Base, California, usually for polar launches. Another launch site is being developed at Boca Chica, Texas.
