maitya wrote:A contrarian viewpoint:
Most modern CCMs (AIM-9X, R-74, Python-5 etc) employ TVC to achieve near-instantaneous 50+ G manoeuvrability - this is vital in an era of HMS and high-off-boresight engagement capability - but this adds to the weight of the overall missile.
ASRAAM of course is an exception - it chose to remain light, by foregoing TVC and is fine with achieving it's 50+G manoeuvrability, a few seconds post launch, using solely it's control surfaces.
This instantaneous achievement of manoeuvrability, is quite critical, for high off-boresight close-in engagements - plus such engagements are, many a times using IRST/LR (and not necessarily the high-off-boresight-challenged-radars - so no additional target info available post-launch etc) which renders the radar-seeker part of the missile a dead-weight (where is the time to establish a range-gate, then track and lock target etc, at such ranges - say 30-40Km).
So until the so-called MRAAMs adds TVC (and thus gain further weight), the SRAAMs will have their relevance, IMVHO.
Also the need to shoehorn a IIR FPA along-with a active-radar seeker (like in MICA series) adds complexity, dimensions and weight (and thus also somewhat sacrifices instantaneous manoeuvrability) - thus the relevance of dedicated SRAAMs will remain.
The CCM's are able to do this -
because there is a requirement for it. (The TVC equipped missiles will get you more instantaneous abilities close to after launch given the motor is burning and speeds are still relatively slow. They'll do better here than most non TVC equipped missiles of their generation).
Likewise, next generation of Medium ranged missiles that will also have a responsibility of replacing these (on top of their performance at extended range) would have to comply with similar requirements. The USAF is expected to ask for additional requirements on end-game agility that needs to be better than current missiles as well. There are ways to do that on clean sheet designs.
Raytheon in its design has added thrust vectoring and larger control surfaces compared to the AMRAAM. This along with half the size of the AMRAAM (lighter and larger proportion of propellant to overall system weight), advances in energetics and propulsion and other technologies will allow it to achieve both those requirements. Lockheed Martin has chosen to keep the aerodynamics relatively clean but have added ACM's to their missile for both initial and end-game agility that will on par or superior to anything we've seen so far. They've also seem to have gone in for a HLG propulsion concepts and other novel SRM technologies that the USAF has matured or funded in the past.
The USAF doesn't seem to want to just slap an IIR seeker on an AIM-120D. That won't allow it to replace the AIM-9 given the 9X's agility. What they want is to develop a missile half the length
of the AMRAAM that is as or more agile than its most agile missile and yet still can get out and hit targets at "AMRAAM" ranges allowing it to replace its two missiles (AMRAAM and AIM-9) with two future missiles (AIM-260 and AIM-X).
From my notes (multiple sources)
Peregrine “combines the range and the autonomy of the AMRAAM with the maneuverability characteristics of the AIM-9X” with extreme maneuverability as it approaches its target.
The Peregrine will have a multi-mode, autonomous seeker that includes infrared imaging. It uses a “new, high-performance propulsion system" to boost speed, Noyes said. He would only characterize the missile’s range as “from visual range to within medium range”..
"The Peregrine is half the length of the AMRAAM. The missile gains its manoeuvrability through thrust vectoring technology that is similar to what is used on the AIM-9X, says Noyes. Noyes also notes the missile is autonomous and has a tri-mode seeker, but declines to say what other sensors the weapon is equipped with".
As can be seen, Lockheed's missile is of very similar size to the Peregrine and both will allow a 2 for one replacement in the same space currently occupied by the AIM-120. Lockheed's missile design uses ACM's which the company has had more than 2 decades of experience with. It could also be carrying TVC but this has not been revealed yet. If prior applications of this are any indication it should handily out maneuver (both initially and end game) anything that the USAF has ever fielded in the past. The range comes from the fact that these missiles are smaller, lighter, have a higher relative propellant mass, utilize more advanced propulsion technologies and carry a LE warhead.
As far as seekers and guidance, Lockheed is probably going to leverage whatever it is doing on the AIM-260. While Raytheon has years of operational experience with dual RF/IIR missiles, Lockheed recently acquired a very small company that specializes in advanced disparate platform (like aircraft and missile) collaborative EW and triangulation and this might have very interesting applications on missiles and missile-platform interaction (think missile carrying a traditional RF seeker and additional ESM gear). Maybe that gets applied to both those missiles..maybe not. But regardless, higher single shot PK is a requirement that they would have to demonstrate against some pretty tough Electronic Attack pod laden QF-16's that the USAF will test it out on.
An indication of what the USAF is looking for (though very general due to the sensitive nature of this).
The "Rear Hemisphere" kill capability is an important requirement that shows up every time the USAF talks about these missiles. This isn't surprising given the F-35's EODAS and the fact that the F-22 will receive similar upgrades and future systems will carry similar or better sensors as well.*
These are likely highly scrubbed designs and probably don't capture the exact details of the missiles being proposed. Lockheed has already tested its missile on the ground and was funded for Air to Air demonstrations by the USAF last year. Expect those to be wrapped up by 2021-2022. Raytheon, has yet to be put on contract but it is quite likely that whatever their design ends up looking like will also be tested in the 2021-2024 time-frame. The idea would be to select down to one and field these systems in the second half of the 2020's.
maitya wrote:Also the need to shoehorn a IIR FPA along-with a active-radar seeker (like in MICA series) adds complexity, dimensions and weight (and thus also somewhat sacrifices instantaneous manoeuvrability) - thus the relevance of dedicated SRAAMs will remain.
The dual and multi-mode seekers won't be used like the traditional set up. They will be used for improved discrimination to the primary sensor. Look at the way Raytheon applied IIR to the standard. Imagining it as a large footprint sensor is not indicative of how it will be used. Same thing when the primary sensor is IIR. You can put a small MMW antennas there for end-game discrimination and as a counter counter measure.
The problem of CM's effecting PK isn't going to be solved by just putting two similar performance sensors in there. They'll just use two types of countermeasures to counter that. What you need is an ability to discriminate between target and countermeasures (like when a towed or expendable decoy is involved) or overcome self-defense measures. Combined RF and IIR sensor solutions are also challenging, particularly when missile is traveling at higher speeds (different scanning abilities of those choices). So you will have to have one sensor as your primary sensor and other that aids it in discrimination. You have to build a hierarchy in there. Without it this concept won't work technically. Doing that on a 5", 6" or 7" missile is not currently technologically limiting. Also RF/IIR is not the only game in town. Multi-Band ESA's have shown promise and the USAF has flight tested a couple as they've advanced that capability through the maturity levels.