SpaceX to make another attempt to launch 21 data satellites for Space Development Agency

3 min read · reported by Spaceflight Now

SpaceX launched a Falcon 9 rocket early Saturday carrying a batch of data satellites for the U.S. military’s Space Development Agency (SDA), five days after a last-minute abort scrubbed the first attempt.

Liftoff from Vandenberg Space Force Base in California is occurred at 12:39 a.m. PDT (3:39 EDT / 0739 UTC). The Falcon 9 took a southerly trajectory on departure from Space Launch Complex 4E, currently SpaceX’s only launch facility on the West Coast.

A launch attempt on Oct. 5 was halted by an auto-abort with 58 seconds remaining on the clock. The halt was triggered moments after the rocket’s onboard computers took control of the countdown. SpaceX said the hold was called due to “some off-nominal data on Stage Two”.

The vehicle was lowered to a horizontal position at the pad for troubleshooting the issue, and the launch was repeatedly pushed back a day at a time.

“Additional time throughout the week allowed for double checks on vehicle systems and range deconfliction,” said SpaceX launch commentator Atticus Vadera.

The range conflict is believed to have been a missile test from Vandenberg that occurred on Friday.

The mission, dubbed Tranche 1 Transport Layer A (T1TL-A), is the fourth mission sending production satellites into orbit for the SDA. This is one piece of a broad constellation — called the Proliferated Warfighter Space Architecture (PWSA) — designed to support the U.S. military and its allies through space-based capabilities, like missile tracking and secure communications.

The mission will used Falcon 9 first stage booster B1103. This was its sixth flight following the launches of the SDA’s T1TL-E, NROL-179, and three batches of Starlink satellites.

About 7.5 minutes after liftoff, SpaceX landed B1103 at Landing Zone 4. This was the 37th landing at LZ-4 and the 668th Falcon booster landing to date.

The T1TL-A mission is one of 23 missions awarded to SpaceX as part of the National Security Space Launch (NSSL) Phase 2 contract awarded in August 2020, which is managed by the U.S. Space Force’s Space Systems Command (SSC). The previous missions from the SDA have already been launched:

The T1TL-B and -E missions featured satellites manufactured by York Space Systems and the T1TL-C satellites were produced by Lockheed Martin. Space Force Col. Ryan Hiserote, SSC’s division chief in Assured Access to Space, told Spaceflight Now back in September 2025 that these initial T1TL missions could be launched in any order.

The 21 satellites flying as part of the T1TL-A mission were manufactured by Northrop Grumman and delivered to Vandenberg Space Force Base on Sept. 28.

Tranche 1 is the initial component of the PWSA constellation is expected to begin providing operational capabilities to the Department of Defense beginning in 2027. When complete, T1 will consist of 126 Transport Layer satellites, 28 Tracking Layer satellites, and four missile defense demonstration spacecraft.

With the three launches completed to date, there are 63 satellites in orbit.

“In close coordination with Space Systems Command (SSC) and Space Launch Delta 30, the deployment of Tranche 1’s proliferated capability will soon deliver continuous overwatch—neutralizing any first-mover advantage by delivering data to warfighters around the world, nearly instantaneously,” said GP Sandhoo, SDA Director and Space Force Portfolio Acquisition Executive for Missile Warning and Tracking following the T1TL-E launch in July.

The SDA said the Transport Layer will consist of between 300 to 500 satellites in low Earth orbit from 750 km to 1,200 km in altitude. The SDA said once complete, 95 percent of the globe will be in view of at least two of the T1TL satellites at any given time.

“The constellation will be interconnected with Optical Inter-Satellite Links (OISLs) which have significantly increased performance over existing radio frequency crosslinks,” the SDA wrote. “LEO orbits in conjunction with OISLs will reduce path loss issues but more importantly offer much lower latencies, which are deemed critical to prosecute time sensitive targets in today’s wartime environment.”

These satellites will be able to integrate with the Link-16 and Integrated Broadcast System (IBS) to allow for “timely threat warnings and situational awareness information”.

The launches of these satellites are managed by the SSC’s System Delta 80 (SYD 80) and the Space Fore Portfolio Acquisition Executive for Assured Access to Space.

Reported by Spaceflight Now. Reproduced unedited by Everything Space. View the original →