Success
SDA Tranche 1 Transport Layer B
Government/Top Secret
SpaceX(SpX)CommercialFalcon 9 Block 5
POorbit
Tranche 1 Transport Layer B 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 York Space Systems.
Wednesday, September 10, 2025 at 2:12 PM
Replay
Flight Timeline
- T-38:00GO for Prop Load
- T-35:00Prop Load
- T-35:00Stage 1 LOX Load
- T-16:00Stage 2 LOX Load
- T-07:00Engine Chill
- T-01:00Startup
- T-01:00Tank Press
- T-00:45GO for Launch
- T-00:03Ignition
- T+00:00Liftoff
- T+01:12Max-Q
- T+02:30MECO
- T+02:34Stage 2 Separation
- T+02:42SES-1
- T+06:24Entry Burn Startup
- T+06:47Entry Burn Shutdown
- T+08:12Stage 1 Landing Burn
- T+08:36Stage 1 Landing
- T+08:38SECO-1
- T+56:43SES-2
- T+56:51SECO-2
Links
Mission details
Orbital Attempt
#7,058
SpX Mission
#566
Pad Launch
#215
Location Launch
#829
Designator
2025-203
Weather GO
100%
Launch Window
NET
Sep 10, 2025, 2:12 PM
Precision
Second
Schedule Changes
1 update
Falcon 9 Block 5 Specs
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.
Length
70 m
Diameter
3.65 m
Launch Mass
549 t
Thrust
7,607 kN
LEO Capacity
22,800 kg
GTO Capacity
8,300 kg
Launch Cost
$52M
Reusable
Yes
Maiden Flight
2018
Fastest Turnaround
1h 5m
Total Launches
586
Successful
585
Failed
1
Consecutive Success
288
Maiden flight: May 11, 2018
Social Flight Log
- Sep 10, 2025, 6:54 PM
Launch success.
Source - Sep 10, 2025, 2:12 PM
Liftoff.
Source - Sep 10, 2025, 1:57 PM
Unofficial Re-stream by SPACE AFFAIRS has started
Source - Sep 10, 2025, 12:35 PM
Now targeting Sep 10 at 14:12:11 UTC
Source - Sep 9, 2025, 3:06 PM
Tweaked T-0.
Source - Sep 5, 2025, 12:50 AM
GO for launch.
Source - Sep 3, 2025, 2:32 PM
Added launch window.
Source - Aug 14, 2025, 1:32 AM
NET September 10.
Source - Jul 15, 2025, 1:51 PM
NET July.
Source - Mar 8, 2025, 3:03 AM
NET late summer. (order of launches per https://sam.gov/opp/7111789df59149cd81596402c35e33d3/view P.12)
Source - Jun 9, 2023, 12:39 PM
Adding launch
Source
Space Launch Complex 4E
Space Launch Complex 4 East (SLC-4E) is a launch site at Vandenberg Space Force Base, California, U.S. The pad was previously used by Atlas and Titan rockets between 1963 and 2005. The pad was built for use by Atlas-Agena rockets, but was later rebuilt to handle Titan rockets.
Total Launches
269
Orbital Attempts
269
Fastest Turnaround
2d 10h
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.
Founded
2002
Administrator
CEO: Elon Musk
Total Launches
681
Successful
666
Failed
15
Pending
120
Consecutive Success
166
Vandenberg SFB, CA, USA
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.
Timezone
America/Los_Angeles
Local Launch Time
Sep 10, 2025, 7:12 AM
Total Launches
885
Total Landings
34
Coordinates
34.7513, -120.5202