SDA Tranche 1 Transport Layer E

Slip history

No changes since we started tracking on Sat 10 Oct 2026, 10:32 UTC.

1. Thu 16 Jul 2026, 22:11 UTCLL2 update

   Launch success.

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2. Thu 16 Jul 2026, 20:33 UTCLL2 update

   Unofficial Re-stream by SPACE AFFAIRS has started

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3. Thu 16 Jul 2026, 20:32 UTCLL2 update

   Liftoff.

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4. Thu 16 Jul 2026, 20:17 UTCLL2 update

   Unofficial Re-stream by SPACE AFFAIRS has started

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5. Thu 16 Jul 2026, 18:50 UTCLL2 update

   Tweaked T-0.

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6. Wed 15 Jul 2026, 20:51 UTCLL2 update

   Tweaked T-0.

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7. Mon 13 Jul 2026, 15:56 UTCLL2 update

   GO for launch.

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8. Wed 8 Jul 2026, 20:08 UTCLL2 update

   NET July 16 per marine navigation warnings, TBC.

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Mission

SDA Tranche 1 Transport Layer E on Falcon 9 Block 5 from Space Launch Complex 4E. Launch time, status and recorded date changes from Launch Library 2.

Tranche 1 Transport Layer E 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.

Mission type

Government/Top Secret

Orbit

Polar Orbit

Launch timeline

Times are relative to liftoff.

1. T-38 minThu 16 Jul, 21:54 CEST

   GO for Prop Load

   Launch director verifies go for propellant load

2. T-35 minThu 16 Jul, 21:57 CEST

   Stage 1 LOX Load

   Start of liquid oxygen loading in the first stage

3. T-35 minThu 16 Jul, 21:57 CEST

   Prop Load

   Start of propelland loading

4. T-16 minThu 16 Jul, 22:16 CEST

   Stage 2 LOX Load

   Start of liquid oxygen loading in the second stage

5. T-7 minThu 16 Jul, 22:25 CEST

   Engine Chill

   Start of engine chilling

6. T-1 minThu 16 Jul, 22:31 CEST

   Tank Press

   Fuel tanks are pressurized to flight levels

7. T-1 minThu 16 Jul, 22:31 CEST

   Startup

   The onboard computer takes control over the countdown and runs last checks

8. T-45 sThu 16 Jul, 22:31 CEST

   GO for Launch

   Launch director verifies go for launch

9. T-3 sThu 16 Jul, 22:32 CEST

   Ignition

   Start of the engine ignition sequence

10. T-0Thu 16 Jul, 22:32 CEST

    Liftoff

    First upwards movement of the rocket

11. T+1 min 14 sThu 16 Jul, 22:33 CEST

    Max-Q

    Maximum dynamic pressure

12. T+2 min 29 sThu 16 Jul, 22:35 CEST

    MECO

    Cut-off of the main engine

13. T+2 min 33 sThu 16 Jul, 22:35 CEST

    Stage 2 Separation

    Separation of the second stage from the first

14. T+2 min 41 sThu 16 Jul, 22:35 CEST

    SES-1

    First start of the second engine

15. T+3 min 21 sThu 16 Jul, 22:35 CEST

    Fairing Separation

    Separation of the payload fairing

16. T+6 min 23 sThu 16 Jul, 22:38 CEST

    Entry Burn Startup

    Start of the atmospheric entry burn

17. T+6 min 46 sThu 16 Jul, 22:39 CEST

    Entry Burn Shutdown

    End of the atmospheric entry burn

18. T+8 min 13 sThu 16 Jul, 22:40 CEST

    Stage 1 Landing Burn

    Start of the first stage landing burn

19. T+8 min 35 sThu 16 Jul, 22:41 CEST

    SECO-1

    First cut-off of the second engine

20. T+8 min 37 sThu 16 Jul, 22:41 CEST

    Stage 1 Landing

    Landing of the first stage

Launch pad

Space Launch Complex 4E

Vandenberg SFB, CA, USA (US)

Coordinates: 34.632, -120.611