Sea Phoenix - or: "How long did Western navies bet on the wrong horse?"


Early shipborne missiles for air defence were quite simple and very much restricted in their capabilities. Some had great ranges, but all of them were rather well-suited for defence against bombers and relatively dumb large missiles (up to light fighter jet size) than for defence against sea skimming missiles or strike fighters flown with attention and skill.

Moreover, the guidance methods required many large antennas, but still limited the quantity of targets engaged in parallel so much that simple saturation attacks were useful for overwhelming them.
The various shortcomings led to the observation that electronic countermeasures (especially decoys and chaff) were actually more effective against missiles than the shipborne air defence missiles.

The obvious saturation attack challenge motivated the West - and the USN in particular - to adopt a modified semi-active radar homing scheme. Early SARH missiles had their target illuminated from launch to hit (or miss). The HAWK missile (homing all the way killer) even explained this in its name. Late 1970's and 1980's tech SARH missiles (examples SM-2 and Patriot) flew by autopilot and had their target illuminated by some radar only during the terminal phase. This allowed for a better trajectory (intercept course, and more close to ballistic), and it reduced the time the illumination radars had to illuminate for one (potential) kill. This helped to increase the theoretical kills during a saturation attack - if only said attack was flown at high-enough altitudes. There were few benefits against sea skimming missiles or strike fighters.

The USN in particular still went all-in on the concept of having giant expensive radars on cruisers and destroyers, air defence coordination rooms in cruisers and lock-on after launch SARH missiles (SM-2) as air defence. ECM and short range air defences were afterthoughts by comparison. The ECM sets were expensive, but the CIWS and short range SAMs (Sea Sparrow) weren't highly regarded.

Eventually, no war ever really tested this AEGIS system (which reached the kind of capability that was supposed in the mid-80's by the mid-90's only) and navy fanbois keep loving it regardless of their knowledge of its shortcomings. There was too much positive propaganda about it.

Still, nowadays it's understood that active radar missiles are the superior alternative. They solve the saturation attack challenge (in theory) by being completely independent from any illumination radar, and they can kill sea skimming missiles before the ship's sensors can see them if only some external sensor provides sufficient and timely target data tot he launching ship. These missiles' active radar seekers furthermore know the distance to their target (SARH only provides 2D directions), so they can calculate a much-superior intercept course in the terminal phase compared to SARH where the missile simply keeps pointing its nose at the return echo's direction. This improves the lethality against manoeuvring targets such as strike fighters. It's at last in theory even possible to re-engage a slow target that's been missed after turning around.

- - - - -

Active radar homing missiles have become available in quantity with the AIM-120 AMRAAM in the early 90's. They are expensive and far from flawless, but it's fair to say that the Western navies overslept the development. AMRAAM arrived in 1991 after long development delays. To introduce an active radar homing missile (Aster) in the late 90's was a significant delay compared to what the air force did - particularly considering that air forces did not face such sea skimming or saturation threats in the same way. Their fighters could run away from overwhelming odds at almost Mach 2. A warship is a static target by comparison.

So Aster was introduced by the late 90's in Europe, SM-6 and Sea Ceptor were introduced in the 2010's and ESSM Block II may or may not arrive in operational service before the 2020's.
So the delay in adopting active radar homing as mainstay of naval air defence is about 6...22 years compare to air combat, right?


The latter missile (or rather system - missile and radar had to be seen in context) was available for shipboard use and very promising during the mid-1970's already!

naval Sea Phoenix installation; launcher and radar
The proposal required the installation of the F-14's radar in a shipboard version together with a launcher box for a dozen Phoenix missiles. This was far from optimised*, but obviously superior to the simple SARH (all the way) Sea Sparrow installations that became NATO standard instead. Some tests were done, and then the USN focused on AEGIS because it emphasised defence against the old school Soviet high-flying missiles instead of against state-of-the art sea skimmers.
Sure, Sea Sparrow was much cheaper, but it was also near-useless against any serious attack. The short range and dependency on SARH would have allowed for one or two kills in theory during an air attack, and the expectation value after taking into account all the fire control issues and probability of kill was rather below one.
Moreover, Sea Phoenix was likely a more capable** air defence proposal than the entire AEGIS system when facing multiple sea skimmers. A destroyer with two illuminator radar may or may not succeed to launch SM-2MR missiles against four incoming missiles before impact (likely rather two). A much smaller ship with much less expensive radar tech but a (rotating launcher) Sea Phoenix set could have fired at 6...12 targets instead.

In other words; there are strong indications that Western navies did bet on the wrong technology horse for 25+ years and are still trying to get out of the technological lock-in after about 45 years. Moreover, betting on the AEGIS/SPY-1/SM-2 horse led especially the USN onto a path towards buying very expensive, very large ships for air defence that provide little advantage over smaller ones if the opposing force is smart or at least matching what the Argentinians were capable of in 1982.***



BTW; Phoenix did cost about half a million dollars, about the same as a Standard ARM which was based on the SM-1 missile. Sea Phoenix may have been not terribly much more expensive than a SM-2 missile after all. It was several times as expensive as a (Sea) Sparrow or Aspide missile, though.

*: Normal 3D ship radar could have been used and the missiles' solid fuel rocket could have been modified for more initial thrust to better suit the surface-to-air role. 
**: Assuming that its radar seeker was appropriately modified to deal with sea skimmers).
***: Super Étendard strike fighter flew very low, climbed shortly to find target ship, approached it very low, launched Exocet missile and turned away without offering a target for a SARH engagement sequence. The Exocet missile flew as sea skimmer and was detected so late that SARH intercept (with the much-respected Sea Dart missile) didn't happen. ECM didn't happen in time either - the ship was hit by the only missile fired. An entire squadron of such pilots, planes and missiles would still be a great challenge for USN cruisers and destroyers today despite the introduction of VLS, ESSM and some conceptual improvements in ECM.


  1. Whilst the basic premise of this article, that active homing missiles are inherently more effective is right, I doubt the Phoenix, at least in its original A model, would have been a lot better than the Standard missile.

    Firstly, my understanding is it required SARH illumination, at least periodically, until within 11 miles of the target. It wasn't datalinked as such. I'm not sure how good a 1970s active seeker would have been against something like an AM39. Lastly, when actually used by the USN in combat, admittedly on only two occasions, it didn't work at all. Having interacted with him personally, I would treat Tom Cooper's information on Iranian phoenix usage as on a par with David Icke's on demonic humanoid reptilian space aliens in our midst. The C model was literally a completely different missile which certainly was capable against sea skimmers, but, by the time it was around, you could have had an active radar SM2, which you belatedly now actually have.

    1. AFAIK the Phoenix failures in combat were missiles past shelf life that had their solid fuel rocket engines failing.

  2. Reminds me of a quotation in my old aircraft book when the F-14/six Phoenix missile launch test happend:
    "Launching six Phoenix missiles is like blowing up a parking lot full of brand new Cadillacs."

  3. The ultimate playground for this was the Falklands. The tactical and technical details of the engagements show how complicated the endeavour is (check out Sea of Fire about the Coventry).

    You're taking a high level approach to the discussion. I haven't got a clue what would have happened if Backfires and Typhoons were volley firing against a carrier group. Maybe 20 years from now there might be some physical based simulation system that can give us an idea.

  4. What kind of difference would an airborne radar have made in the Falklands? Would the extra notice have been significant, or would the comm/ data links of the time have been too slow to be useful?

    1. HMS Sheffield could have used chaff and turned bow or stern towards the missile. That wouldn't require AEW, though.
      HMS Glasgow detected the threat in time and reacted properly. HMS Sheffield had its ESM made useless by an active SATCOM at the time.