BAE Systems passes the critical design review for MEO Epoch 2, ten satellites designed to track ballistic missiles and hypersonic glide vehicles from space.
In Summary
BAE Systems has just passed one of the major milestones of the U.S. missile defense space program, MEO Epoch 2. The group announced on September 21, 2026, the completion of the Critical Design Review for this constellation of 10 detection and tracking satellites, funded to the tune of $1.2 billion by the U.S. Space Force. Space Systems Command had communicated as early as September 8 on the validation of the first two orbital planes. This step now authorizes the full industrialization of the satellites. Placed in Medium Earth Orbit, they will use electro-optical and infrared sensors to detect and track both ballistic missiles and hypersonic gliders, which are more difficult to observe. MEO Epoch 2 will complement the 12 satellites of Epoch 1 as well as architectures placed in low Earth and geostationary orbits. The first delivery of Epoch 2 is scheduled for fiscal year 2029.
The Critical Review Unlocks Production of the Ten Satellites
BAE Systems announced on September 21, 2026, that it had completed the Critical Design Review, or CDR, for the U.S. Space Force’s Resilient Missile Warning & Tracking – Medium Earth Orbit Epoch 2 program.
The timeline is worth clarifying. Space Systems Command had already announced on September 8 the successful review covering the first two orbital planes of Epoch 2. BAE Systems then formalized its own passing of the industrial milestone on September 21.
The CDR is not a mere administrative formality. It verifies that the detailed design meets performance, safety, and operational requirements before committing the bulk of manufacturing.
The program was awarded to BAE Systems on May 29, 2025, in the form of a firm-fixed-price Other Transaction Authority agreement valued at $1.2 billion. Only fourteen months separate the contract award from the critical review.
However, it would be inaccurate to say that all manufacturing begins today. BAE Systems had already purchased long-lead components and launched advance manufacturing of certain elements. The CDR primarily authorizes the transition to much more comprehensive production.
The Ten Satellites Must Track Hard-to-See Targets
MEO Epoch 2 belongs to the new U.S. Missile Warning and Tracking architecture. Its objective is no longer limited to detecting the launch of a missile.
Legacy space warning systems are particularly effective against an intercontinental ballistic missile during its boost phase. The engines produce an intense infrared signature at that time. The launch appears as a highly visible heat source from space.
An hypersonic glide vehicle poses a different problem. After being accelerated by its booster, the glider travels through the atmosphere at speeds exceeding Mach 5. It can alter its flight path and fly lower than a payload following a classic ballistic trajectory.
Its signature is also weaker than that of a rocket engine at full thrust. The system must therefore detect a dimmer target, distinguish it from the Earth’s background, and then maintain its track as it maneuvers.
This is precisely why hypersonic missile detection is becoming a central component of new anti-missile architectures.
Medium Orbit Complements Satellites in LEO and GEO
The ten Epoch 2 satellites will be placed in Medium Earth Orbit. Medium Earth Orbit is generally located between approximately 2,000 and 35,786 km in altitude, or between 1,243 and 22,236 miles.
This choice represents a compromise.
Geostationary satellites, at roughly 35,786 km, continuously observe vast regions. However, their distance requires powerful sensors to distinguish weak infrared signatures.
Low Earth Orbit brings sensors closer to missiles. It improves resolution and reduces latency, but requires a large constellation to ensure continuous coverage.
MEO sits between the two. It allows for broad coverage with fewer satellites than LEO while bringing sensors closer to targets compared to a GEO architecture.
The U.S. Space Force is therefore not choosing one orbit over another. It is building a multi-layered architecture. The concept links satellites in LEO, MEO, GEO, and certain highly elliptical orbits.
This approach also forms one of the building blocks of the concept outlined in the U.S. project for missile defense systems against hypersonic threats.
Infrared Sensors Form the Heart of Epoch 2
Each Epoch 2 satellite is designed to receive an electro-optical and infrared sensor, a communications payload, and advanced processing capabilities directly onboard.
This latter function is essential. Systematically transmitting raw data to the ground would slow down the detection chain. Onboard processing makes it possible to begin recognizing a signature, establish a track, and share information even before full analysis on the ground.
The satellites will also feature data crosslinks to exchange information between platforms.
BAE Systems will utilize its Trek space bus, derived from the Elevation product line. This platform can support payloads up to 1,000 kg and provide up to 1,900 watts of average electrical power in orbit. It features a precise attitude determination and control system, essential for keeping an optical sensor pointed at a fast-moving target.
Much of this technology stems from the former Ball Aerospace, acquired by BAE Systems in February 2024 for $5.5 billion. The transaction provided the British group with an experienced American industrial base in optical instruments, satellites, and space payloads.
Epoch 2 Complements Twelve First-Generation Satellites
MEO Epoch 2 does not arrive into an empty space.
Epoch 1 provides for 12 satellites spread across two orbital planes. They constitute the first operational MEO layer of this new architecture. Deliveries are organized in successive waves so that the Space Force can introduce new technologies without waiting for the replacement of an entire constellation.
Epoch 2 will add ten additional satellites across two orbital planes. The first delivery is scheduled during fiscal year 2029.
At this stage, the two generations are expected to bring the MEO fleet to 22 satellites.
The principle is intentionally incremental. Subsequent Epochs are intended to arrive every two to three years. The Space Force can thus modify sensors, computing capabilities, or communications as threats evolve.
This proliferation of space sensors accompanies a much broader transformation of the military role of space, already visible in projects involving space-based missile defense.
The Real Challenge Remains Missile Track Custody
Detecting a launch is not enough to intercept a hypersonic weapon.
A missile defense system must maintain track custody—that is, continuous knowledge of the target’s position and trajectory. A gap of just a few tens of seconds can become critical when facing a craft traveling several kilometers per second and capable of changing direction.
The satellites must therefore rapidly transmit their observations to other elements of the network. Epoch 2 is designed to operate with existing and future systems, notably satellites from the Space Development Agency and assets from the Missile Defense Agency.
This architecture is intended to progressively transform space warning into a chain capable of providing data precise enough to prepare an interception.
The challenge is considerable. Spotting a hypersonic target is one thing. Following it continuously, predicting its flight path, and passing an actionable solution to a weapon system is another.
Space Force Now Prioritizes Resilient Constellations
The move of Epoch 2 into production also reflects a departure from the historical U.S. model.
For decades, missile warning relied on a small number of high-performing and extremely expensive satellites. This architecture provided exceptional coverage, but concentrated capability into a few platforms.
Washington is now seeking to multiply satellites and orbits. The loss or unavailability of a single spacecraft should no longer suffice to create a major breach in surveillance.
The stated goal for Epoch 1 and Epoch 2 is ambitious: ultimately enabling the tracking of a hypersonic threat anywhere in the world.
The CDR passed in September shows that this strategy is progressively moving out of architecture studies and into manufacturing. BAE Systems’ ten satellites will not solve the hypersonic weapons challenge on their own. Their value stems from precisely the opposite: they will be one link in a much broader network in which every orbit, sensor, and link must prevent the target from disappearing between observations.
It is this continuity, even more than the speed of future interceptors, that will determine whether the United States can truly transform early warning into effective missile defense against maneuvering targets.