For decades, the military has tried – with little success – to build missiles capable of traveling at breakneck, hypersonic speeds. Missile tests, however, have been uneven, with repeated failures punctuated by the occasional stunning success. Now the Air Force is taking a bigger role by seeking to build another hypersonic missile, this time for its stealth fighter 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 at speeds of Mach 5 for 200 seconds after launching it off a B-52 bomber. A later test, though, ended with engine failure.

Unlike those weapons, though, the High Speed Strike Weapon isn't a so-called "Global Strike" weapon. Those weapons are supposed to hit anywhere on Planet Earth at any time. The former Falcon missile, for instance, was designed to launch with a rocket into space, before screaming back down to Earth and obliterating its target. But those weapons are indistinguishable from a nuclear weapon when seen on radar – which could inadvertently trigger nuclear Armageddon once a surprised nuclear power like Russia sees one in the air.

A fighter-launched missile resembles any other smaller, non-nuclear missile. It's just traveling super-fast. Armageddon averted.

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.