Falcon 9 Block 5 | SDA Tranche 2 Transport Layer C

### Falcon 9 Launches SDA Tranche 2 Transport Layer C Mission

On October 31, 2026, SpaceX's Falcon 9 rocket lifted off from a launch site in the United States, carrying a classified payload for the Space Development Agency (SDA). Designated as the SDA Tranche 2 Transport Layer C mission, this launch marked a significant step in bolstering the U.S. military's space-based communication infrastructure. While details remain shrouded in secrecy due to national security concerns, the mission aligns with the SDA's broader efforts to deploy a constellation of satellites designed for resilient data transport and tactical communications.

The primary objectives of the Tranche 2 Transport Layer revolve around creating a proliferated low-Earth orbit (LEO) network that enhances military operations. This layer is part of the SDA's Proliferated Warfighter Space Architecture (PWSA), which aims to provide secure, low-latency data links for global forces. The payload, likely consisting of multiple small satellites, focuses on capabilities such as optical inter-satellite links, advanced encryption, and real-time data relay. These satellites are engineered to withstand jamming and other threats, offering redundancy in contested environments. Payload capacities for such missions typically include sensors for tracking and targeting, with each satellite weighing around 100-200 kilograms and featuring modular designs for rapid deployment. This setup allows for quick constellation replenishment, a departure from traditional large-satellite architectures that are more vulnerable to disruption.

At the heart of the launch was the Falcon 9 Block 5, SpaceX's workhorse reusable rocket. Standing 70 meters tall with a diameter of 3.7 meters, the Falcon 9 consists of two stages: the first powered by nine Merlin 1D engines producing over 7.6 million newtons of thrust, and the second by a single vacuum-optimized Merlin engine. The Block 5 variant, introduced in 2018, incorporates upgrades for enhanced reusability, including reinforced heat shields, titanium grid fins, and improved landing legs. It can deliver up to 22,800 kilograms to LEO in expendable mode or about 15,000 kilograms when the first stage is recovered. The rocket's fairing, measuring 5.2 meters in diameter, accommodates payloads like the SDA satellites, which are stacked for efficient deployment. Fueling relies on subcooled liquid oxygen and RP-1 kerosene, enabling rapid turnaround times—often within days for reused boosters.

The Falcon 9's performance history underscores its