WASHINGTON — The U.S. Army has approved the Sentinel A4 radar program, critical to the service’s future air defense capability, to move into low-rate initial production, the program executive officer for missiles and space said.
Now that the Lockheed Martin-developed Sentinel A4 is approved, with a total of 19 systems scheduled for delivery by fiscal 2025, the Army is preparing for an initial operational test and evaluation during the same time frame, Maj. Gen. Frank Lozano told Defense News in an Aug. 22 interview.
The Sentinel A4 active electronically scanned array is the next-generation radar planned to replace the current phase and frequency scanned array in Sentinel A3 and earlier versions. The air and missile defense radar is able to detect cruise missiles, drones, rockets, artillery and mortars, and it can simultaneously identify and track different threat types.
The Army has worked on a way to defend against cruise missiles for years. As mandated by Congress, the service procured two Iron Dome systems as an interim solution, developed by Israeli company Rafael Advanced Defense Systems and U.S. firm RTX, as it develops an enduring Indirect Fire Protection Capability, or IFPC, that will protect fixed and semi-fixed sites against rockets, artillery and mortars as well as drones and cruise missiles.
The Sentinel A4 will tie into the Army’s future Integrated Air and Missile Defense Battle Command System, or IBCS, as well as the IFPC, still under development.
“There’s been a lot of discussion over the last five to seven years regarding cruise missile defense and a lot of impetus on making sure we’ve got a good IFPC system,” Lozano said. “Sentinel A4 is a key component of that because I’m not shooting anything down, [from] a cruise missile defense perspective, unless the radar sees it first. So we have a really high-quality radar to make sure that we can get that missile to the right point in time and space at the right time to have a successful intercept.”
In addition to Sentinel tying into IFPC and IBCS, it will also serve as the radar for the defense of the National Capital Region along with the National Advanced Surface-to-Air Missile System developed by Norwegian company Kongsberg, according to Chandra Marshall, vice president of Lockheed’s radar and sensor systems business. The radar will also be part of an air and missile defense architecture under development for the defense of Guam.
The Army is embarking on a test campaign for integrating fires capabilities beginning this year and running annually through at least 2027, Lozano told Defense News in a separate interview. Sentinel A4 will be tied into the test campaign in FY25.
Once the initial operational test and evaluation phase concludes, the Army can obtain a materiel release in the fourth quarter of FY25 to begin fielding the Sentinel A4 to units. Lozano said that, as of now, the Army’s acquisition objective for the radar is 240 systems, which would deliver the capability to a minimum of six IFPC battalions.
“Sentinel is funded to support those six battalions. IBCS is funded in its [program objective memorandum] to support those six battalions. IFPC is funded to support those six battalions. And now I just have to deliver the capability and make sure it works,” Lozano said.
The Army built five systems for soldier evaluations conducted over the past several years, and the service is building five more for delivery this year to support developmental tests leading up to the initial operational test and evaluation phase.
The Sentinel A4 program has moved quickly, according to Marshall, because Lockheed took advantage of commonality from its other radars like the Q-53 radar that can track unmanned aerial systems. That commonality is expected to help the service when it comes to sustainment, she added.
The soldier evaluation process over the past several years generated “generally” positive feedback, Lozano said. “We have gotten some comments regarding maintenance operations where we could make improvements on the maintenance procedures associated with certain [line-replaceable units], components or cables. Those are pretty minor tweaks.”
Soldiers have also provided feedback on how to improve emplacement of the system in operational environments. But, Lozano added, “what we believe is driving some of those comments on operations is associated with the fact those soldiers are familiar with the A3, and therefore some of the employment operations and some of the operator actions associated with the radar functioning in its normal operation environment are just different … the user interface is slightly different.”
The Army plans to resolve the adjustment from A3 to A4 with training, Lozano explained.
“We want to make sure our systems are user friendly,” Marshall said. “As we get the feedback from the soldiers … we’ll make the updates and then have the soldiers on the system to see if we’ve addressed, satisfactorily, the ease of operation of the system.”
Jen Judson is an award-winning journalist covering land warfare for Defense News. She has also worked for Politico and Inside Defense. She holds a Master of Science degree in journalism from Boston University and a Bachelor of Arts degree from Kenyon College.