Back in November 2010 the Capability Development and Planning Division of the Aeronautical Systems Center (part of the U.S. Air Force's Materiel Command) issued a presolicitation notice announcing that it was "conducting market research analyses to examine applicable materiel concepts and related technology" for a next generation tactical aircraft with an initial operating capability "of approximately 2030." The fighter was expected to "operate in the anti-access/area-denial environment that will exist in the 2030-2050 timeframe," thought likely to include "advanced electronic attack, sophisticated integrated air defense systems, passive detection, integrated self-protection, directed energy weapons, and cyber attack capabilities."
It is the mention of directed energy weaponry that really got my attention. Predictions regarding directed-energy weapons have proven consistently overoptimistic, with projects like the Nautilus and the Airborne Laser turning out to be serious disappointments. (Indeed, Israel has turned to the guided missiles of the Iron Dome air defense system rather than lasers to shoot down short-range rockets.) Much like the flying car, they have simply not happened. Might that change in twenty to forty years' time? Perhaps.
It also seems noteworthy that the directed-energy weapons are mentioned as part of the threat environment – and not the aircraft's own armament. Some technologies start small and get bigger (as has often been the case with vehicles), while others start big and get smaller (like computers), and directed-energy weapons seem very likely to be in the latter category, as the programs mentioned above indicate. Speaking intuitively, I'd say that the appearance of lasers or microwave weapons small enough to fit inside a tactical aircraft and at the same time powerful enough to justify their weight are extremely unlikely between now and 2050. Though I wouldn't be surprised if they also failed to appear, larger, ground- or sea-based air defense weapons don't seem wholly outside the realm of the possible.
Assuming they do appear, what would that appearance mean for combat aircraft? Obviously speed-of-light weapons cannot be dodged, the way jets dodge surface-to-air missiles. It does not even seem to me likely that the next generation of fighters will even be much faster or higher-flying than they are now (given how unlikely hypersonic flight seems for a multi-mission aircraft like the one discussed in the notice).1 Yet, techniques comparable to those we now have for building stealth aircraft, and mounting "hard" suppressive attacks (like using anti-radiation missiles against radars) could remain on the table. So would the use of decoys and jamming to blind or trick the fire control systems of attacking weapons and other sensors, and it may even be possible to jam the beam of the weapon itself – just as communications and sensors based on lasers and microwaves can be jammed. And just as missile casings can be thickened to make them more resistant to the energy of a laser beam, aircraft might (up to a point) be armored.
Exactly how these factors will interact is at this point beyond the scope of reasonable extrapolation, not least because it depends on still other factors – like the race between stealth technology and radar. However, were laser weapons to prove capable of effectively targeting vast numbers of sophisticated attackers, they might make the use of expensive, high-performance strike aircraft prohibitively costly, and drive a turn to large numbers of simpler, cheaper drones or stand-off missiles instead. Such a turn may make the platforms succeeding the F-22 and its counterparts in their mission so different as to constitute not a sixth-generation jet fighter, but the first generation of something else.
1. The presolicitation notice envisages a multi-mission aircraft, capable of performing not just "Offensive and Defensive Counterair," but "Integrated Air and Missile Defense," "Close Air Support" and "Air Interdiction," and possibly also "airborne electronic attack" and "intelligence-surveillance-reconnaissance capabilities."
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