Kristen Smith 
- Leidos will supply the infrared sensing payloads for all 18 satellites Sierra Space is building under SDA’s AMDT3 program
- Each payload pairs infrared sensing with onboard signal processing
- Leidos already has four Tranche 0 payloads in orbit and is under contract for more on Tranche 1 and 2
Sierra Space has selected Leidos to build the infrared sensing payloads for 18 satellites it is producing under the Space Development Agency’s Accelerated Missile Defense Tranche 3, or AMDT3, program. Leidos announced the subcontract Monday.
SDA awarded Sierra Space roughly $798 million in July for those spacecraft, part of about $1.75 billion split with L3Harris to deliver 36 vehicles for the tracking layer of the Proliferated Warfighter Space Architecture. The constellation supports Golden Dome for America.
What Will Leidos Supply to Sierra Space?
Each payload from Leidos will pair infrared sensing with digital signal processing that will run on board the Sierra Space satellites. Leidos said handling that computation in orbit cuts latency, putting usable tracking data in the hands of operators sooner than a ground-based approach would.
The company’s scope reaches past the hardware to ground support equipment, operations support and sustainment through the life of the program.
“Leidos has already demonstrated these technologies on orbit, and with Sierra Space, we will rapidly transition that proven capability into an operational missile defense constellation that will help protect the nation against advanced missile threats,” said Cindy Gruensfelder, president of Leidos Defense and a 2026 Wash100 Award winner.
What Does AMDT3 Add to the Tracking Layer?
The 36 AMDT3 spacecraft will occupy four orbital planes and are slated to be ready for launch by the end of 2028. SDA designed them to work alongside its Tranche 1, Tranche 2 and Tranche 3 satellites and to run through a shared ground system.
The Sierra Space vehicles carrying the Leidos payloads will handle missile warning and tracking. L3Harris is building the other 18 as missile-defense variants modeled after the Hypersonic and Ballistic Tracking Space Sensor.
What Has Leidos Delivered on Earlier Tranches?
Four Leidos payloads from Tranche 0 have been operating in orbit since 2023, and the company said they have produced tracks of real-world events.
Leidos is also under contract for 14 missile warning and tracking sensors on Tranche 1 and 16 on Tranche 2, as well as two dedicated missile defense sensors for the second tranche.
