Infrared payloads for SDA

Missile-tracking satellites need infrared eyes that can spot a hot launch plume against the cold of space. General Atomics said April 21 it won a subcontract from Lockheed Martin to supply those sensors for the Space Development Agency’s Tranche 3 Tracking Layer. (ga.com) Lockheed Martin is one of the prime contractors on the program. The company said on Dec. 19, 2025 that the Space Development Agency awarded it a contract worth more than $1 billion for 18 Tranche 3 tracking satellites. (lockheedmartin.com) The Space Development Agency said the full Tranche 3 Tracking Layer buy covers 72 satellites. On Dec. 19, 2025, the agency announced awards to Lockheed Martin, Northrop Grumman and York Space Systems for those spacecraft. (sda.mil) The basic idea is a mesh of many smaller satellites in low Earth orbit instead of a few large ones in higher orbits. The agency says the Tracking Layer is meant to provide global, persistent warning, detection, tracking and identification of missile threats, including hypersonic systems. (sda.mil) Infrared payloads are the part of the satellite that detects heat, much like a thermal camera sees a warm engine at night. The Space Development Agency’s Tracking Layer fact sheet says each tracking satellite carries an infrared sensing payload to detect and track missile signatures from low Earth orbit. (sda.mil) Tranche 3 is larger than the minimum constellation the agency outlined earlier in the procurement. A draft solicitation released in 2024 said the buy was expected to include at least 54 infrared-equipped satellites in six orbital planes, with the fully deployed Tracking Layer estimated at more than 100 spacecraft. (sda.mil) The new subcontract also extends an existing supplier lineup. Lockheed Martin said in 2025 that its Tranche 2 tracking satellites use Terran Orbital buses and infrared missile-tracking payloads from General Atomics Electromagnetic Systems. (lockheedmartin.com) The Space Development Agency has pitched Tranche 3 as a step up in both scale and sensor performance. SpaceNews reported in late 2024 that the tranche would use more sensitive infrared sensors aimed at higher-fidelity tracking for missile defense, not just early warning. (spacenews.com) That distinction has drawn scrutiny as the program grows. SpaceNews reported in February that a Government Accountability Office review flagged risks in the missile-tracking effort, even as the agency pushed ahead with new procurements. (spacenews.com) For General Atomics, the award keeps its infrared hardware in the next round of a fast-cycle Pentagon satellite build. For the Space Development Agency, it locks in another piece of a low-orbit missile-tracking network that is already moving from prototypes to larger production buys. (ga.com)