Modernization is not defined solely by hardware; it requires change in the ways we organize and employ forces. We must anticipate the implications of new technologies on the battlefield, rigorously define the military problems anticipated in future conflict, and foster a culture of experimentation and calculated risk-taking.
—2018 National Defense Strategy of the United States of America:
Sharpening the American Military’s Competitive Edge
The People’s Liberation Army Navy (PLAN) presents a growing undersea threat. “Vital maritime terrain” and novel ways of employing existing platforms offer an opportunity to conduct offensive antisubmarine warfare (ASW) operations in forward-deployed teams.1 In a December 2021 article—“Build Expeditionary ASW Air-Combat Elements”—we took inspiration from the 1942 Guadalcanal campaign’s ad-hoc combination of Marine Corps, Navy, Army Air Forces, and allied aviation known as the Cactus Air Force and named the new construct the Cactus21 ACE (air combat element).2
Formed out of existing platforms and units, a Cactus21 ACE could be implemented rapidly with minimal developmental cost—vital considerations in the face of the “Davidson Window” for a Chinese invasion of Taiwan and the expectation that U.S. military budgets will flatten or even decline significantly.3
The aircraft available to form a Cactus21 ACE include the Navy’s MH-60R Seahawk, MH-60S Knighthawk, and MQ-8C Fire Scout and the Marine Corps’ MV-22B Osprey. Navy CMV-22B Osprey units might eventually join the team, and P-8A Poseidon aircraft could lend tactical support from distant airfields located outside the enemy’s long-range weapons engagement zone (WEZ). Once proven as an operational construct, Cactus21 ACEs could incorporate nontraditional ASW platforms, such as Spearhead-class expeditionary fast transport ships (EPFs) and allied ASW units, such as MH-60R aircraft from foreign partners already operating the world’s preeminent ASW helicopter.4 The entire operation would fall neatly in step with two larger initiatives: the Chief of Naval Operations’ drive to build a robust naval operational network architecture with Project Overmatch and the joint Navy–Marine Corps focus on expeditionary advanced base operations (EABO) and the littorals.5
Humans More Than Hardware
The Sea Services already possess most of the tools necessary to implement a Cactus21 ACE. The 19 MH-60R squadrons in the helicopter maritime strike (HSM) community and the 18 MH-60S/MQ-8C squadrons of the helicopter sea combat (HSC) community have decades of experience in expeditionary operations both ashore and embarked. In many ways, operating a Cactus21 ACE from an aviation-capable ship would be similar to deployments on board amphibious ships during the East Coast’s hurricane season or Task Group Greyhound guided-missile destroyer (DDG) ASW operations confronting Russian submarine threats in the Atlantic.6 MH-60R aircrew in HSM units are established experts in ASW operations, and HSC MQ-8C operators possess the preponderance of the Navy’s deployed unmanned aerial system (UAS) experience.
The Navy also currently has sufficient human capacity to support these operations. As naval aviation transitions to the “Air Wing of the Future,” additional F-35C, E-2D, and MQ-25 aircraft on aircraft carrier flight decks will mean less room for embarked MH-60 aircraft.7 The displaced helicopters and personnel thus will become available and ready assets, well suited for expeditionary operations away from carrier strike groups. HSM and HSC squadrons could also provide ready command elements to deploy forward with a Cactus21 ACE in a manner similar to the traditional Marine Corps practice of forming ACE command-and-control functions around the incorporated MV-22 squadron’s leadership.
To become fully capable ASW aircraft, Knighthawks and Fire Scouts will need minor capability improvements that could be accomplished quickly and cheaply. The MH-60S needs upgrades to employ lightweight torpedoes, but the associated technical planning has already been completed.8 In fact, much of the additional cost could be offset by dropping its capability to employ AGM-114 Hellfire missiles, M197 20-mm cannons, and 2.75-inch rockets, because these weapons require operation too close to their targets to be of more than minimal utility against a peer adversary. The MQ-8C needs to add a sonobuoy processor and electronic support measures detection capability, but those efforts are already underway.9 The other Cactus21 platforms could join the ASW fight today without any modifications.
Because the ships and aircraft already exist, the Navy–Marine Corps team should immediately begin experimentation with the Cactus21 concept. The Southern California Tactical Training Range (SCTTR), an established and instrumented ASW training area around San Clemente Island, would serve as an outstanding testing ground familiar to local HSC, HSM, and Marine medium tiltrotor squadrons (VMM) based locally at Naval Air Station (NAS) North Island, Marine Corps Air Station Miramar, and Camp Pendleton. As an added benefit, U.S. submarines homeported at Naval Base Point Loma in San Diego could serve as “targets” when operations permit.10
After establishing baseline tactical concepts, the Cactus21 ACE could develop operational methodology by conducting ASW exercises from EABs on San Clemente Island and while embarked on board participating DDGs, EPFs, and amphibious assault ships. These also could be sourced locally, from Naval Base San Diego. This would allow for comprehensive, integrated training within 80 miles of the Cactus21 homeport, simplifying coordination and logistics while simulating geographic dislocation from their main supply base. P-8A aircraft from NAS Whidbey Island in Washington could augment the ASW exercise while operating at the extreme edge of their combat radius in a fashion similar to their likely employment in a potential Pacific war.11
Finally, after forming the team and refining operational concepts during domestic training, the Cactus21 ACE should join existing overseas exercises to incorporate allied and partner navies. Participating in these exercises would help develop the doctrine and tactics around expeditionary ASW operations and build trust between likely partners before a future conflict. Best of all, this plan could come together in the next three years, in time to be relevant before the Davidson Window opens wide in the second half of this decade.
A future Cactus21 ACE could operate from a remote base in the vicinity of a strategic maritime strait inside the enemy’s potential antiship cruise missile WEZ. MV-22s provide supplies from an expeditionary sea base or LPD stationed outside the enemy’s WEZ to a mobile EAB that alternates among many temporary locations ashore. While transiting home, the Ospreys systematically hand-launch sonobuoys to augment previously deployed sensors in a strait. 12 An MQ-8C rides on a flatbed trailer to a different temporary location ashore and begins a ten-hour mission to monitor the sonobuoy field. On an LCS disguised from enemy sensors among the heavy civilian maritime traffic, an MH-60R sits in an alert launch posture, with a single Mk 54 lightweight torpedo. An MH-60S, capable of carrying two Mk 54s as part of an “Alert ASW” loadout flying from an EPF in shallow water, delivers supplies from the EAB (hub) to the associated ships operating in nearby waters (spokes). During these “normal” flight operations, two enemy submarines attempt to simultaneously breach the strait.
Because of Project Overmatch’s resilient network, all members of the task force gain immediate awareness of the threats detected by the buoy field. The MH-60R launches to localize, classify, and destroy one submarine using its lone Mk 54. The MQ-8C localizes and classifies the second submarine before the MH-60S arrives to kill the target with one of its two torpedoes. This ACE is one of many similar units positioned hundreds of miles apart astride all the key maritime terrain surrounding the enemy’s naval forces. Instead of relying solely on ASW defense around high-value units, friendly forces are on offense and killing enemy submarines before the boats present a significant threat.
A P-8A Poseidon could add significant capability to all phases of the expeditionary ASW mission, including prosecution of enemy submarines like those in the example. However, Poseidons will be in high demand during any future conflict and may not be available when needed.13 Furthermore, large targets such as the P-8A will be vulnerable to surface-to-air and air-to-air attacks when operating in the boundary layer between U.S. and enemy forces. It would not take significant planning for an enemy to coordinate its submarine transits with available offensive counterair sorties by fighter aircraft or surface-to-surface long-range fires against airfields capable of supporting P-8A operations. Manned and unmanned helicopters offer the advantages of availability in large numbers, the ability to operate from an array of supporting bases both ashore and afloat, and the survivability inherent in low-altitude operations.
The MQ-8C and MH-60S are essential to Cactus21 ASW operations, but both require minor capability upgrades to join the ASW fight. The Fire Scout needs a sonobuoy processing capability. Otherwise, the most readily available platform capable of monitoring the sonobuoy field would be the MH-60R—a manned aircraft with limited endurance. The enemy submarines in the example could easily slip through the strait while the MH-60R was on deck refueling or undergoing routine maintenance between sorties. Similarly, without developing an MH-60S torpedo capability, at least one of the two hypothetical enemy submarines would have survived its transit through the strait and disappeared. Because the MH-60R would typically be limited by gross weight to carrying just one torpedo, the weapons on board the MH-60S Knighthawk would be vital in case of an ineffective attack and/or multiple targets appearing in an operating area.
Overmatch Proving Ground
The Cactus21 capability also would be a new approach enabled by Project Overmatch’s “networks, infrastructure, data architecture, tools, and analytics . . . that will enable our sustained maritime dominance,” in the words of Chief of Naval Operations Admiral Michael Gilday.14 By networking and dispersing the sensor platforms, processing platforms, and attacking platforms, the resulting naval operational architecture (NOA) would thus multiply the collective capabilities and allow for truly distributed maritime operations.
Cactus21 stands in stark contrast to the legacy method for ASW operations, in which the same platform deploys the sensors, monitors them, and conducts the resulting prosecution of enemy targets. According to Rear Admiral Doug Small, commander of Naval Information Warfare Systems Command, “Overmatch is not necessarily just about connecting weapons and sensors. . . . Overmatch is about decision advantage.”15 A Cactus21 ACE would serve as an outstanding testbed for the developing NOA and an avenue to immediately capitalize on the resulting mission capabilities.
A Cactus21 ACE would be well suited to operate in the distributed and potentially disconnected environment envisioned by the triservice maritime strategy Advantage at Sea.16 Because its assigned mission could be boiled down to a simple directive (e.g., do not let any submarines transit this strait), each Cactus21 ACE would capitalize on what Admiral Scott Swift described in his 2018 essay, “Master the Art of Command”: “clear and widely understandable commander’s guidance and intent before communications and networks are put at risk.”17
Since the Cactus21 ACE concept capitalizes on already proven units and technology, it would pose minimal developmental risk. There are other technological innovations in the acquisition pipeline that also could add to U.S. ASW capabilities, such as the compact rapid attack weapon, but these capabilities may not be ready before the latter part of this decade.18 The Cactus21 ACE is just the sort of expedient operational innovation the U.S. Navy needs to meet an imminent threat.
Time and Tide
The threat from the China is “manifest during this decade,” in Admiral Davidson’s words.19 The U.S. Navy must innovate to meet this challenge, including a significant and concerning growth in the PLAN’s submarine force.20 However, this innovation cannot be limited to laboratories and technological development. To deter and potentially defeat Chinese aggression this decade, the U.S. Navy must develop new operating concepts using the tools already at hand. The Cactus21 ACE concept is just this sort of innovation, and the resulting combat capability would be ready when needed.
1. Secretary of the Navy, Advantage at Sea: Prevailing with Integrated All-Domain Naval Power (Arlington, VA: Department of the Navy, December 2020), 13.
2. CDRs Matt Wright and Jamie Powers, USN, “Build Expeditionary ASW Air-Combat Elements,” U.S. Naval Institute Proceedings 147, no. 12 (December 2021).
3. Mallory Shelbourne, “Davidson: China Could Try to Take Control of Taiwan In ‘Next Six Years,’” USNI News, 9 May 2021; and Jim Garamone, “Chairman Discusses Future Defense Budgets,” DOD News, 3 December 2020.
4. Naval Sea Systems Command, “Expeditionary Fast Transport (EPF): Program Summary,” updated January 2019, www.navsea.navy.mil; and Lockheed Martin, “Why 7 Countries—and Counting—Choose MH-60R for their Toughest Maritime Missions.”
5. “Chief of Naval Operations Memorandum to Rear Admiral Douglas W. Small, Subject: Project Overmatch,” 1 October 2020; and Advantage at Sea, 7.
6. LTJG Caroline Leya, USN, “SURFLANT Stands Up Task Group Greyhound,” SurfLant Public Affairs, 28 September 2021.
7. Mallory Shelbourne, “A Generational Change in Naval Aviation Has Begun amidst Tight Budgets, Fighter Gaps,” USNI News, 24 March 2022.
8. Unclassified Information Paper, “Utilization of Lightweight Torpedo by MH-60S,” OPNAV N98, 10 January 2012.
9. Sam LaGrone, “Northrop Grumman Pitching Fire Scout Helicopter Drone for ASW Missions,” USNI News, 16 February 2021.
10. Department of the Navy, U.S. Pacific Fleet, “Southern California Range Complex Coastal Consistency Determination,” 1–24.
11. Naval Air Systems Command, “P-8A Poseidon.”
12. U.S. Marine Corps, Tentative Manual for Expeditionary Advanced Base Operations (Washington, DC: February 2021), 1-6.
13. Capt Walker D. Mills, USMC, and LCDRs Collin Fox, Dylan Phillips-Levine, and Trevor Phillips-Levine, USN, “Implementing Expeditionary ASW,” U.S. Naval Institute Proceedings 147, no. 4 (April 2021).
14. “Chief of Naval Operations Memorandum to Rear Admiral Douglas W. Small,” 1 October 2020.
15. Megan Eckstein, “Navy Remains Mum on Project Overmatch Details So China Won’t Steal Them,” Defense News, 25 February 2022.
16. Advantage at Sea, 7.
17. ADM Scott Swift, USN, “Master the Art of Command and Control,” U.S. Naval Institute Proceedings 144, no. 2 (February 2018).
18. Mikayla Easley, “Navy on Cusp of Awarding Contract for New Torpedo,” National Defense, 18 April 2022; and Justin Katz, “Navy to Pick New Torpedo in March 2022 Following Delay,” Breaking Defense, 16 December 2021.
19. Shelbourne, “Davidson: ‘China Could Try to Take Control.’”
20. Congressional Research Service, “China Naval Modernization: Implications for U.S. Navy Capabilities—Background and Issues for Congress,” 18 March 2022, 15.