SDA Tranche 1 Transport Layer A

Mission: SDA Tranche 1 Transport Layer A

Government/Top Secret · Polar Orbit

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.

Customers: SDA

What it put in orbit

COSPAR ID 2026-231. Orbits from the CelesTrak satellite catalogue (perigee × apogee, inclination).

Where to watch

Timeline

1. T−00:38:00 GO for Prop Load
2. T−00:35:00 Stage 1 LOX Load
3. T−00:35:00 Prop Load
4. T−00:16:00 Stage 2 LOX Load
5. T−00:07:00 Engine Chill
6. T−00:01:00 Tank Press
7. T−00:01:00 Startup
8. T−00:00:45 GO for Launch
9. T−00:00:03 Ignition
10. T+00:00:00 Liftoff
11. T+00:01:04 Max-Q
12. T+00:02:14 MECO
13. T+00:02:18 Stage 2 Separation
14. T+00:02:25 SES-1
15. T+00:02:31 Booster Boostback Burn Startup
16. T+00:03:04 Fairing Separation
17. T+00:03:24 Booster Boostback Burn Shutdown
18. T+00:06:09 Entry Burn Startup
19. T+00:06:21 Entry Burn Shutdown
20. T+00:07:15 Stage 1 Landing Burn
21. T+00:07:19 Stage 1 Landing

In the news

• SpaceX to make another attempt to launch 21 data satellites for Space Development Agency Spaceflight Now, 9 Oct 2026
• Rocket Report: A rare Falcon 9 scrub; is it just about Vulcan's time to shine? Arstechnica, 9 Oct 2026
• Launch Preview: Flights from South Korea, China, USA planned for this week NASASpaceflight, 5 Oct 2026
• Live coverage: SpaceX to launch 21 data transport satellites for the Space Development Agency Spaceflight Now, 4 Oct 2026

Headlines via the Spaceflight News API.

Updates

• Launch success. source
• Liftoff! source
• Unofficial Re-stream by SPACE AFFAIRS has started source
• Tweaked T-0. source
• Tweaked T-0. source
• Delayed to NET October 10. source
• Delayed to NET October 9. source
• Delayed to NET October 8. source
• Tweaked T-0. source
• Unofficial Re-stream by SPACE AFFAIRS has started source
• Unofficial Re-stream by SPACE AFFAIRS has started source
• Unofficial Re-stream by SPACE AFFAIRS has started source
• Confirmed rescheduled for October 6. source
• Scrubbed for the day. source
• Hold at T-00:58. source
• Unofficial Re-stream by SPACE AFFAIRS has started source
• Now targeting Oct 05 at 08:18 UTC source
• Tweaked T-0. source
• Now targeting Oct 05 at 08:17 UTC source
• GO for launch. source
• NET October 5 per marine navigation warnings, TBC. source
• NET October. source
• NET September. source
• NET mid-February. source
• Delayed to NET early 2026. source
• NET March 2025. source
• NET late 2024. source
• Adding launch source