Pentagon Weighs Adding Airborne Moving Target Indication (AMTI) Capabilities to Tranche 3 Missile Defense Satellites
The Space Development Agency (SDA) is exploring the possibility of incorporating satellites designed to track airborne moving targets into its next iteration of missile defense satellites, known as Tranche 3. This ambitious plan was revealed by outgoing SDA Director Derek Tournear in a recent interview.
Deliberations Underway
„It’s all a little bit preliminary at this point,” Tournear cautioned. „There’s discussions right now happening within the department, as well as with Congress, on the proper way to do that, and the timing of it.” He indicated that the current plan involves including AMTI capabilities as part of Tranche 3, with a solicitation expected to be released soon, pending ongoing deliberations on specific details.
A Collaborative Effort
The Space Force, Air Force, and US Northern Command have been collaborating to demonstrate space-based sensors for the airborne moving target indication (AMTI) mission. This initiative is considered a partial replacement for the Air Force’s E-3 Sentry, with a target date around 2030. However, the Trump administration’s decision to cancel the E-7 Wedgetail, intended to replace the E-3, has cast some doubt on that timeline.
Former Space Force Deputy for Operations, Cyber, and Nuclear, Lt. Gen. DeAnna Burt, mentioned an ongoing analysis of alternatives for space-based AMTI, expected to conclude this fall.
Integrating AMTI into the Missile Custody Layer
Tournear explained that the concept is to integrate the new AMTI satellites into SDA’s missile custody layer, a component of the agency’s Proliferated Warfighter Space Architecture (PWSA). The PWSA consists of hundreds of satellites in low Earth orbit (LEO). SDA envisions its custody layer as a hybrid constellation of government and commercial satellites, providing near-real-time ground target tracking and targeting information to operators.
„When we talk about custody layer, we talk about target custody, right? I’ve always said that that is our ability to detect and track moving targets on the ground and sea, and now also in the air,” he stated.
A Shift in Strategy
Previously, SDA intended to rely on other entities, such as the Air Force, the Intelligence Community, and the commercial sector, to develop and build intelligence, surveillance, and reconnaissance satellites. These partner satellites would then be integrated into the PWSA and its Transport Layer data relay constellation.
„But now things have changed a little bit, and SDA is actually looking at flying AMTI satellites as part of our custody layer,” Tournear revealed.
Overcoming Technological Challenges
The AMTI satellites would utilize „radar-based systems” to detect missiles in flight. Tournear acknowledged the significant challenges involved, emphasizing that it is „incredibly difficult.”
A key challenge stems from the fast orbital speed of LEO satellites, limiting their observation time over a specific area to approximately seven to ten minutes. Missiles also travel at extremely high speeds.
Radar system capability depends on power and aperture (antenna size). Proliferation helps overcome this difficulty by increasing the chances of aircraft being close to satellites.
„Historically that has been prohibitively expensive. And that’s why this has never been done from space before. It cost too much to build very large antennas and field them,” Tournear said. „But there’s been so many advancements in the commercial industry. … There’s several companies out there that are building very affordable antennas that could be proliferated to be able to enable this mission.”
A Feasible Future
Despite the obstacles, Tournear expressed confidence that space-based AMTI is now achievable.
„I would say that we are at the point now where the technology has matured and it’s commoditized, so that radar based AMTI from space is feasible.”
