While the now operational and newly arrived Air Force F-15EX Eagle II may not, by most estimations, rival its fifth-generation counterparts, in large measure due to a broad consensus that there is indeed an imperative for stealth given the sophistication of enemy air defenses, there are a handful of what could be considered highly impactful, if not groundbreaking elements of the new jet.

Many of these attributes reside in the areas of networking, computing, EW, radar, and threat warning systems, yet the new F-15EX does incorporate several potentially paradigm-changing propulsion technologies and attack weapons possibilities. The F-15EX is not only engineered with new levels of thrust, but also carries twelve missiles as well as elements of its existing or well-known arsenal, including the AIM-120D, AIM-9x, and standard JDAMS, among others. While there have been massive software upgrades to the AIM-120D and AIM-9x enabling improved targeting guidance, jamming countermeasures, and explosives, some of the newer weapons additions could potentially be even more groundbreaking.

The F-15EX will, for example, carry and fire air-launched hypersonic weapons, a decided combat advantage that requires little introduction, as their arrival will naturally transform modern air war when it comes to speed of attack, enemy response time, and stand-off attack range. An air-fired missile traveling at five times the speed of sound would certainly hit air or ground targets operating hundreds of miles away in a matter of minutes, all but eliminating an enemy’s ability to respond in time. The Air Force has now also armed its F-15E with the well-known Stormbreaker weapon, a first-of-its-kind air-dropped bomb able to find, track, and destroy moving targets from distances as far as forty nautical miles in all weather conditions. Not only does the Stormbreaker utilize a two-way data link enabling it to adjust course in flight according to a target’s movements, but the weapon is engineered with an often-discussed tri-mode seeker. The tri-mode targeting and sensing technology draws upon Millimeter Wave, infrared, and laser targeting guidance to track and eliminate targets.

The Raytheon-built Stormbreaker can also operate as a certain kind of countermeasure to an extent, given that its seeker can adapt to switch targeting modes in the event that one method of guidance is jammed, blocked, or thwarted by an enemy. This builds in a key element of redundancy, particularly because the Stormbreaker was developed with inertial measurement, GPS, and radio datalinks such as LINK 16. The multiple modes of guidance and navigation could therefore ensure that the weapon continues on to its target in the event that GPS guidance is jammed, denied, or taken away by an enemy.

For instance, should a group of enemy fighters seek to maneuver under heavy cloud cover or during a sandstorm or blizzard, laser-spot targeting or even GPS could be quite challenged. Millimeter Wave, however, is an all-weather targeting guidance system, able to move through or overcome line-of-sight challenges which can cause laser beam attenuation. Infrared targeting could also, for instance, find the heat signature emitting from an enemy armored vehicle and strike through certain weather conditions as well.

Perhaps in part, for this reason, Millimeter Wave (mmWave) technology, is increasingly being woven into weapons guidance systems. Millimeter Wave is defined as small wavelengths with frequency ranges between 30 and 300 GHz where a total of around 250 GHz bandwidths are available, according to ScienceDirect. As with other kinds of radar, the higher the frequency, the more precisely configured the return signal, a technical phenomenon that can enable a munition to alter course upon detecting movement or position changes.

The small wavelengths of mmWave frequencies enable large numbers of antenna elements to be deployed in the same form factor thereby providing high spatial processing gains, as stated in a 2017 publication called mmWave Massive MIMO, a Paradigm for 5G.

Does all of this mean that an F-15EX could successfully compensate for a lack of stealth with these kinds of weapons guidance technologies, much longer attack ranges, increased sensor sensitivity and fidelity, high-speed computing, and threat warning detection? Is there any way the advanced F-15EX could actually compete with a Chinese J-20 or Russian Su-57? The answers to this may not be fully clear and full of a host of differently interpreted variables. If an F-15EX had the long-range sensors, varied guidance systems, advanced computing, threat library identification data, and vastly improved weapons reach, could it destroy enemy air defenses or fifth-generation platforms without having to engage itself in close proximity? Should an F-15EX operate with the sensing, AI-enabled computing, threat identification, and radar technology, and long-range weapons guidance systems in any way comparable to existing fifth-generation aircraft, then there certainly may be an argument for deploying the F-15EX in a major power warfare scenario amid an attack campaign aimed at establishing air superiority against an advanced rival. After all, part of the rationale for F-35 superiority is based upon the notion that it is designed to find and kill multiple enemy aircraft, and air defenses, before it is itself even seen. Could this be possible for a non-stealthy F-15EX Eagle II? Perhaps. Yet arguably not at the same time, as stealth is considered by many to be an indispensable attribute when it comes to countering advanced air defenses.

This may be the thinking on the part of advocates. However, many fifth-generation advocates are likely to insist that only a true, stealthy fifth-generation aircraft could succeed in those kinds of advanced, ultra high-threat great power war scenarios. Some have gone so far as to suggest that an advanced fourth-generation aircraft might linger in a kind of liminal zone, meaning it may be far too advanced for counterinsurgency, yet not capable of engaging the most high-end great power threats. fifth-generation advocates also make the case for what’s called cost-benefit, meaning that even if a single F-35 is more expensive per aircraft than other options, far fewer F-35s can, it is argued, perform the mission of multiple fourth-generation aircraft, therefore saving money.

These, it seems, may be the most fundamental and pressing questions informing ongoing debates about funding, threat indicators, cost value, and other factors as they contribute to planning regarding air fleet asset configuration. The debate is not likely go away, and its resolution may depend in large measure on how each aircraft performs. Perhaps, ultimately, a combination of both aircraft would be optimal? Such thinking may eventually carry the day. The question is: what is the numbers mix between them? That is to be determined.

Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters’ Degree in Comparative Literature from Columbia University.

Image: Reuters.