SpaceX Waves Off SDA Tranche 1 Transport Layer A, Retargets Oct. 10

SpaceX has stood down from the Thursday, Oct. 8, 2026 attempt to launch the Space Development Agency’s Tranche 1 Transport Layer A mission from Space Launch Complex 4 East at Vandenberg Space Force Base, the third time the launch has been called off since the Monday, Oct. 5 countdown stopped in the final minute. The company is now targeting no earlier than Saturday, Oct. 10 at 12:29 a.m. PT (3:29 a.m. ET), with a backup on Sunday, Oct. 11 at 12:32 a.m. PT (3:32 a.m. ET).

On Oct. 5, SpaceX said Falcon 9 “had an auto abort just prior to T-0” and that the “vehicle and payload are in good health,” with teams resetting for an attempt no earlier than Oct. 6. SpaceX has not said what caused the abort.

SpaceX then passed on the Oct. 6 opportunity, which had been set for 1:17 a.m. PT, without giving a reason, and retargeted Thursday, Oct. 8 at 12:54 a.m. PT. On Wednesday evening, Oct. 7, it moved the launch again, posting that it was “now targeting no earlier than October 10” and that “the rocket and payload remain healthy, and additional time allows for double checks on vehicle systems and range deconfliction.”

New Target And Backup

SpaceX’s mission page lists liftoff for Saturday, Oct. 10 at 12:29 a.m. PT from SLC-4E, with the Sunday, Oct. 11 slot at 12:32 a.m. PT if needed. Both attempts remain West Coast night launches. The first-stage booster, which Next Spaceflight lists as B1103, is making its sixth flight, after NROL-179, SDA’s T1TL-E and three Starlink missions, and the page still calls for it to land on Landing Zone 4 at Vandenberg after stage separation. That’s an onshore return, so no need to drag a droneship out to sea and back for this one.

The Oct. 5 abort happened as the countdown moved into automated startup, with an update around 4:28 a.m. EDT. Whether Saturday’s new timing holds will depend on recycling work, weather, and range clearance.

SpaceX has not published a refreshed go/no-go yet, but we’ll likely see one within an hour of the estimated target launch time.

What T1TL-A Carries

The flight is SDA’s fourth Tranche 1 data-transport mission — SpaceX titles it “SDA’s Fourth Tranche 1 Mission” — and one of nine Tranche 1 missions Falcon 9 is flying for the agency. The payload is 21 data-transport satellites that form the fourth orbital plane of SDA’s Proliferated Warfighter Space Architecture, a low-Earth mesh of optically linked spacecraft built for military tactical communications and missile warning, indication, and tracking.

Air & Space Forces Magazine reported on Oct. 2 that this is the first Tranche 1 mission carrying Northrop Grumman-built satellites, joining 63 Tranche 1 spacecraft already on orbit from York Space Systems and Lockheed Martin. Spaceflight Now said the Northrop satellites arrived at Vandenberg on Sept. 28.