Is an unpublisized missile being used as a major selling point for the F-35 Joint Strike Fighter (JSF)? With constant delays and cost overruns is Lockeed Martin attempting to entice potential F-35 buyers by combining the sale with a smaller derivative of the X-51? Is this smaller missile being advertized in confidential forums as a "game changer"?
If the missile is a miniaturized derivative of the X-51 it would be a hypersonic, very advanced missile indeed. The smaller missile might be "paper" only or perhaps under US development and may not be mature until delivery of the F-35 to foreign customers from 2018-2020 onwards. Such a missile would need to be small enough to fit within the F-35's stealthy body. Hypersonic speed is generally considered Mach 5 or above.
The JASSM is now coming into service with the USAF and Australian Airforce (RAAF). It may be that the JASSM, nominally considered subsonic, is actually supersonic if it incorporates the type of engine technology used to power the "super cruise" F-22 Raptor.
There may be an end run for the JASSM where the warhead detaches and then accelerates into the high supersonic to hypersonic range. Such acceleration in a vertical dive might be heavily reliant on a rocket motor. Given some artillery shells now have rocket assist the incorporation of such a feature in the JASSM's 450 kg (1000 lb) WDU-42/B penetrator warhead is quite possible.
A third possibility is a mixed propulsion missile equivalent to the already developed Indian-Russian BrahMos. The majority of flight for such a missile may be subsonically perhaps using a turbojet, then alter its flight profile moving to a high supersonic or hypersonic end run powered by a ramjet, scramjet or rocket engine. See this article from Defense Update of February 6, 2013 "Aero-India 2013: The Indian Air-Force Plans to Induct BrahMos by 2015" concerning deployment of BrahMos including air-launching it from India's fighter-bombers http://defense-update.com/20130206_the-indian-air-force-plans-to-induct-brahmos-by-2015.html .
Higher velocity in all three missile possibilities provides a greater element of surprise, with it increased survivability as its harder to shoot down a faster missile - with reduced time for the target to deploy flares or other decoys. A faster missile also has higher kinetic energy to penetrate earth/rock/concrete (or a ship's hull) more deeply.
High kinetic energy would be particularly sought after by the US and Israel with regard to Iran's (and perhaps North Korea's) deeply dug in nuclear sites.
What caught my eye was a transcript of Four Corners "Reach for the sky" documentary on Australia's ABC, February 18, 2013 http://www.abc.net.au/4corners/stories/2013/02/18/3690317.htm :
"[civilian presenter] ANDREW FOWLER: And it's even got a weapon that's a closely guarded secret.
LT. GENERAL CHRIS BOGDAN, EXECUTIVE OFFICER, F-35 JOINT PROGRAM OFFICE: Those are the crown jewels of the program and that's what makes the F-35 special.
ANDREW FOWLER: So asserting that to the public, it's really saying 'trust us'?"
I then spotted the following article: Wired - Danger Room June 7, 2012 reports http://www.wired.com/dangerroom/2012/06/hypersonic-missiles/ :
"Air Force Wants Hypersonic Missiles for Stealth Jets"
The Air Force’s desired “High Speed Strike Weapon” would travel at five times the speed of sound or faster, theoretically launching from a stealthy F-22 Raptor jet or a future F-35 Joint Strike Fighter, and traveling so fast and at such long distances as to render an enemy’s anti-aircraft systems defunct. The Air Force’s Research Laboratory Munitions Directorate is gathering possible design partners later this month at Elgin Air Force Base in Florida before any solicitation. According to an Air Force notice, whatever prototype gets built will ultimately need to strike “time-critical” targets — on the move, possibly — from “tactically relevant standoff distances.”
If it can be done, the weapon will “be representative of an air-breathing hypersonic missile system” that can tough it out in “the most stringent environments presented to us in the next decade,” said Steven Walker, the Air Force’s deputy assistant secretary for science, technology and engineering, in written testimony to the House Armed Services Committee in February.
That’s the hope, at least. The U.S. military has a mixed record with hypersonics. Last August, the Pentagon’s pizza-shaped Falcon Hypersonic Technology Vehicle 2 failed for a second (and likely final) time, crashing into the Pacific during a test flight.
But the Army’s Advanced Hypersonic Weapon did much better during a test in November. Two years ago, the Air Force successfully flew its X-51 WaveRider scramjet missile http://www.wired.com/dangerroom/2007/06/mach_5_missile_/ at speeds of Mach 5 for 200 seconds after launching it off a B-52 bomber. A later test, though, ended with engine failure.
...There are other technical challenges in launching a scramjet missile from a fighter jet instead of a sub-orbital rocket or a B-52, though. It’ll still need to have air-breathing engines that compresses the air around the missile into a supersonic mixture of oxygen and fuel — absent a turbine.
But it will also need to be small enough to be carried by a jet fighter while carrying the necessary advanced navigation controls, precision guidance tools and sophisticated sensors, plus the warhead. The service will also still have to find the right mixture of composite materials like titanium and tungsten (among others) to hold up under the enormous heat generated by Mach 5, Mach 6 and even faster flight.
The Air Force is requesting a whopping 150 percent increase in funding for the program, from $6.2 million now to $15.4 million in 2013 in one “thrust” of weapons development, according to subscription-required InsideDefense. That’s a lot of money for a missile that may not work."
The sales strategy for the F-35 may therefore be heavily reliant on the missile that comes with the sale - if that missile already exists or can be completed by 2018.