AGM-88E AARGM
The US Navy is the Lead Service for the AGM-88 family of weapons, with the latest US Navy-developed version, the AGM-88E Advanced Anti-Radiation Guided Missile (AARGM) now in ser vice with the US Navy, the US Marine Corps and Italian Air Force. Developed and built by Orbital ATK (Northridge, CA) with Italian partner MBDA (Rome, Italy), the AARGM offers considerable improvements and capabilities over the standard HARM.
With an IOC in 2012, AARGM incorporates an advanced digital anti-radiation homing (ARH) sensor with improved frequency coverage, GPS/Inertial navigation, as well as an integrated, millimeter wave (mmW)-radar seeker for terminal guidance. A digital terrain elevation database (DTED)-aided GPS/ INS restricts the missile's impact zone to prevent collateral damage. It also includes an organic in-cockpit emitter targeting and situational awareness capability. The weapon system also has a weapons-impact-assessment transmitter which provides information prior to impact for additional situation al awareness. The 54-inch-long missile can be carried externally by F/A-18, Tornado, EA-18G, F-16, EA-5B, and F-35 aircraft.
As described by Mike Stuart, Director Weap ons and Advanced Programs Business Development, Orbital ATK Defense Electronic Systems Division (Northridge, CA), "If you look at how AARGM first evolved (in the 2000/2001 timeframe), it was initially a strictly ARH-kind of approach involving a purely GPS-type of solution that would ensure restricted and controlled target areas. But, the Navy said, 'Suppression is great, but by turning on and off their radars, adversaries are still maintaining effective ness, and we need to be able to hit those targets.' Add to that the evolution of GPS jammers, together with the possibility of also adding a millimeter-wave targeting capability, and the preference for destruction vs. suppression took hold at that point."
CAPT Albert Mousseau, Program Man ager for Direct and Time Sensitive Strike Weapons (PMA-242) at Naval Air Systems Command (NAVAIR) in Patuxent River, MD, says, "It really comes down to each Service's view of the requirement, but the DON recognized that the problem (with strictly suppression) is that you have to keep going back every day, or whenever there's a mission, and force them into that mode, so the threat is still there. Because of that, the Navy opted to pur sue ways to transition, not so much away from suppression, but toward an ensured destructive capability, so we didn't have to address the same threat repeatedly."
The ultimate approach was to incorporate GPS-specificity benefits to restrict and maintain the weapon's focus within a specified target area, which, as Captain Mousseau says, would not only prevent unintended collateral damage, but also improve error rates and allow the ARH seeker to home in on emissions quicker and with more accuracy. "And, by then also adding the millimeter- wave seeker, if the target radar system does shut down, you still have an active seeker that can steer to wherever you believe the target to be, and prosecute from that perspective. The threat sys tem no longer has that sanctuary."
Says Stuart, "All programs evolve as the threat evolves, and as such, when seekers could handle the types of threats they faced at the time, and were able to track and engage them, people were okay with them. The US Navy saw the need to move on from the legacy HARM and migrated to a digital receiver set with a conformal array and, most importantly from a terminal-guidance perspective, added a millimeter- wave, end-game targeting radar." Says Captain Mousseau, "This fusion allowed for improved effectiveness to meet the requirement that was defined in the capabilities document - specifically targeting or looking to counter a threat's observed abilities to shut down when they know that there are anti-radiation missiles in the air."
Orbital ATK is still producing the AGM-88E AARGM for both the US and Italy, and it will be for some time. The company just delivered systems from its full-rate production (FRP) 3 contract and is now manufacturing missiles for delivery under the FRP 4 contract. Captain Mousseau says the Navy has already awarded through FRP 5 and "we will continue to award for the next several years until we meet our quantity requirement for baseline AARGM. We're also anticipating delivery of a software-only upgrade to the weaponin 2017 to further enhance its capability." The FY2017 budget re quest includes $4.2 million of research and development funding for the AARGM Block 1 follow-on development and test program. It also includes $178.2 million for AARGM weapons production of 253 AARGM rounds including captive training missiles.
NEXT-GENERATION HARM - THE AARGM-ER
Launched in FY2016, the US Navy's AARGM Extended Range (AARGM-ER) program is aimed at the next evolution of the HARM and the AGM-88E AARGM itself, with the primary objective to provide the system with a longer-range capability. Says Captain Mousseau, "It's clear that the evolving threat has a range envelope into which we don't want to enter. We're seeing that across the board, not just in EW systems, but all of our weapon systems. One of the ways to deal with this is to extend the range of our weapons, and AARGM-ER is one example of where the DON will be pursuing that goal over the next several years.
Extending the AARGM's range not only provides improved survivability of the employing aircraft, but also survivability of the weapon itself as it gets into the terminal area. Right now, extended range is our biggest focus, and that means putting in a bigger back-end to support the front-end of the seeker." Legacy AGM-88 HARM missiles, as well as both the AGM-88E AARGM and AGM-88F HCSM, all have the same propulsion system, so their ranges are basically equivalent. The AARGM-ER, however, is to provide a substantial increase in range over all current systems. In February of this year, PEO (U&W), Direct and Time Sensitive Strike Weap ons Program Office (PMA-242), held an industry day to solicit information from potential sources to work with Orbital ATK to conduct risk identification and reduction activities for a new propulsion system for the AARGM-ER, and to subsequently develop the system. A Milestone B decision to enter Engineering and Manufacturing Development (EMD) is expected in 2018.
In November 2016, the Navy awarded Orbital ATK a sole-source $14.3 million contract for engineering studies and de sign analyses of the AARGM front end, including assessments related to plat form-interface compliance, structural integrity, thermal capabilities, mmW performance, and overall ARH effectiveness. This work is also expected to be completed in May 2018, followed by a Milestone B decision. FY2016 RDT&E funds in the amount of $2.6 million were obligated to the effort at the time of award.
According to Captain Mousseau, the AARGM-ER program is continuing to follow the HARM modular design and modification model working with Orbital ATK to understand if there any modifications that will need to be made to the front end currently in production. "It's difficult to say if we're looking at changes at this point, but the expectation is that there will be a need to do some modifications. AARGM-ER will be operating in a different flight regime, which is why we're doing the design analysis. We want to make sure we understand what kind of technical challenges may be there, so we understand the risks and to help us allocate the appropriate resources to those risk areas to ensure that we can meet the delivery schedule of the weapon system by 2023." For its part, Raytheon has also submitted an AARGM-ER design concept and participated in the recent Industry Day event.
F-35 INTERNAL CARRIAGE
The AARGM-ER effort also includes modifying the design of the missile for internal carriage on both the F-35A and F-35C Lightning II aircraft. Although funding is currently not allocated for the actual integration effort, which will involve the F-35 program office, PMA-242 is working on the form/fit modifications that will be required. As described by CAPT Mousseau, "First off, the size of the current weapon system will need to be compressed in order for it to fit internally on the aircraft. AARGM is a bit too long. We'll also have to remove its mid-body wings, which will more than likely be moved to the aft end of the missile making it a tail- pellant? This is part of the rocket motor risk initiative engagement work going on with industry right now, and part of the front-end design analysis. As we gain understanding of the techni cal implications and risks, we'll need to maintain engagement with our resource sponsor to make sure they understand any potential impact on budget and schedule. AARGM-ER is not an acceler ated program, and we need to be smart about it, conducting kind of rolling en gineering reviews, so that we'll contin ue to inform our acquisition leadership as to any technical challenges that we'll need to address, so that by the time we get to the Milestone B decision in 2018, everyone will be well informed on the risks associated with the program."
Although Orbital ATK's Stuart recognizes that the Navy has not yet made an official determination, "continuing to pursue options, assessing the threat
Looking ahead to the possibility of integrating the AARGM or AARGM-ER onto an unmanned aerial systems (UAS), Captain Mousseau says that's not currently part of their efforts.
"The focus has been on manned platforms as of to day, and although I can't say what could potentially happen 12-months from now as we continue to learn more about what AARGM-ER will be dimensionally, I would submit, that any suitable UAS would have to able to handle a fairly heavy payload. The FY2017 budget request includes $43.1 million in RDT&E funding for AARGM-ER development. As to the number of systems that are expected to ultimately be procured, Captain Mousseau says, "We have a range that we've provided to industry, but there is no definitive number, as of yet." The AARGM program existing Italian partners are informed as part of the current MOA of the Navy's intention to upgrade the weapon system whereupon they can make a determination whether or not they wish to participate. To date, how ever, they are not a participant in the AARGM-ER program.