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Prompt Global Strike

Prompt Global Strike, the Pentagon’s idea for a weapon that can be launched from the United States and hit a high-value target anywhere on Earth in an hour or less has been around for a while.

Some envision this weapon as resembling an ICBM armed with a conventional warhead instead of a nuclear payload. This makes some sense — ICBMs launched from the U.S. can strike their targets on the other side of the world extremely quickly.

The problem with putting a conventional weapon on an ICBM is that nations like Russia might think the U.S. is lobbing a nuke the second an unannounced ballistic missile launch appears on their radar screens. Needless to say, that wouldn’t be a good situation.

So, how do you make it obvious that your ICBM doesn’t have a nuke on board? It’s all in the trajectory, according to Boeing officials.

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It looks like the Pentagon’s plans to develop a prescision weapon capable of hitting anywhere on Earth with a conventional warhead in a matter of minutes or hours will remain alive for the time being.

Soon-to-be incoming Pentagon chief Leon Panetta told lawmakers during his confirmation hearings to be Secretary of Defense that he supports the effort to field such a weapon.

From his written testimony via Defense News:

Conventional prompt global strike (CPGS) weapons would provide the nation with a unique conventional capability to strike time-sensitive targets, so that distant, hard-to-reach places will no longer provide sanctuary to adversaries.  It is my understanding that the only current prompt global strike capability in the U.S. inventory is a nuclear armed ballistic missile.  CPGS would be a valuable option for the President to have at his disposal.

CPGS systems could be useful in scenarios involving regional adversaries considering an attack using weapons of mass destruction or against high-priority non-state adversaries.  More broadly, CPGS may be the only systems available in situations where a fleeting, serious threat was located in a region not readily accessible by other means.

Now, the Air Force says that it’s not planning on sticking a conventional weapon atop a ballistic missile. The most compelling arguement against doing so is that the rapid launch of an ICBM with little to no warning to other nations (see Russia) could make people think the U.S. was launching some sort of nuclear weapon.

So rather than an ICBM, the Air Force may develope hypersonic vehicles that would be booster to around Mach 6 and then use a sramjet-style engine to continue on to the target at such speeds. In fact, the Air Force already looking at ways to weaponize the technology used on its main hypersonic research vehicle, the X-51A Waverider.

However, as Defense News points out, it’s unclear if the Pentagon will have the cash on hand to fund such a program in the age of government austerity. Especially since it’s going to be competing with new aircraft carrier programs, the F-35 Joint Strike Fighter, the next generation bomber and several new ground vehicle programs.

Speaking of the X-51A, its second test flight happened earlier this week and it was considered, well, “less than successful” after the vehicle’s engine refused to fully start. This is the second time in as many flights that the X-51A has seen its test shot cut short.

A manufacturing flaw led to the early termination of last May’s test flight of the Air Force’s X-51A Waverider hypersonic vehicle, according to Air Force officials.

The historic flight out of the Naval Air Station Point Mugu in California was terminated by safety officials about half way through its mission when the Air Force lost contact with the vehicle due to hot engine gases seeping into the aircraft’s body through a seam separating the engine and airframe.

A significant portion of the X-51A’s actual engine is mounted on the bottom of the aircraft, as seen in the picture above. A weak interface between that and the exhaust nozzle mounted on the back of the vehicle allowed hot engine gases to flow into the actual airframe. This started melting wiring packets and other critical parts, including those that transmit data back to flight controllers. Never a good thing for a flight.

“Because of those hot gases we were starting to have telemetry problems” in receiving flight data a the control center, said Charlie Brink, the Air Force Research Laboratory’s X-51A program manager during a March 15 call with bloggers. “At that 143 second point, we lost it, they did the [five second safety] count, we didn’t hear back from it so the Point Mugu folks hit the button and we terminated it.”

The Waverider was supposed to fly for about 300 seconds, reaching a speed of Mach 6. Instead, it only flew for 143 seconds hitting a max speed of Mach 5 before Point Mugu safety officials killed the flight by ordering the craft’s control surfaces to suddenly pitch, sending the X-51A cartwheeling rapidly toward the sea.

Brink says that a misread of the design team’s intentions by the builders of the X-51A led to a weak seam between the exhaust nozzle on the vehicle and the actual engine.

“There was some discrepancies in what I would call design intent, meaning what that designers wanted to happen and what the folks down in Florida put that installation together,” said Brink. “The interface was rather complex, it was the first time we ever put the vehicle together so there was no indication of sloppy workmanship of things like that. In a demonstrator you learn things and as you start talking to people and you go ‘oh, that’s what you meant, i didn’t understand the nuance of what you were calling out in that drawing’.”

In the months since, the Air Force has made the interface between engine and nozzle “a lot more robust,” added Brink.

The next flight is slated for March 22.

The technology being tested out in the Air Force’s X-51A Waverider hypersonic missile platform may soon shift from far-out tech to becoming an actual weapon, service officials revealed this week.

“There are a number of initiatives and plans in the works,” to shift “the technologies that are in the X-51A to start transitioning those technologies to a more weapons friendly design,” said Charlie Brink, the Air Force Research Laboratory’s X-51A program manager during a March 15 call with bloggers.

While none of these plans have been fleshed out into an official program of record to weaponize the X-51A, it could mean that we see a new generation of hypersonic weapons developed using the technology proven by the Waverider.

One example of this is the fact that the Air Force may look at shrinking certain parts found in the X-51A such as the engine control computer. Right now, the aircraft uses the same one found on the F-22. However, this is a bit overkill according to Brink, who described it as “bigger box and more robust computing capability” than needed to help guide a vehicle like the Waverider.

Instead, the service would like to see parts like that get smaller, freeing up more space for fuel, sensors and stuff that goes bang; like, you know, warheads.

“Those are the kind of technologies that we would like to start working on and integrating into a hypersonic demonstrator down the road,” said Brink.

He then confirmed that there is R&D money socked away to start working on how to do just that.

Eventually, the Air Force will decide whether or not to modify the X-51A airframe or use its technology as the basis for a new vehicle, he added. The service has a road map on how to come to this decision, he said.

Many have speculated that hypersonic vehicles like the X-51A could be used as a sort of super cruise missile to fulfill the Air Force’s requirement for a conventional weapon that can strike any target on earth from the continental U.S. in a matter of minutes or hours after the target is ID’d.

The Air Force is prepping for the second ever live-fire test shot of the X-51A on March 22. Last year, the X-51A took a 140 second flight at speeds up to Mach 5. That flight was terminated before the Waverider could reach its planned speed of Mach 6 due to design flaws that we’ll go into tomorrow here at DT.


Looks like its official, the Air Force won’t be using any type of ICBM to carry conventional warheads around the world at record speed to carry out the Prompt Global Strike mission. There have been lots of questions about how the service would achieve it’s plan hit high value targets on almost any spot on the globe within hours or minutes of a strike being ordered.

One option was the notion of a conventional ICBM. A problem with that idea was that a lot of people worried an ICBM launch would be confused as a nuclear first strike. Not something you want to have happen.

Now it seems the Air Force has ruled that out. According to Defense News:

The U.S. Defense Department’s planned Conventional Prompt Global Strike (CPGS) weapon is likely to be a hypersonic glider, a senior U.S. Air Force official said.

“Our focus is on boost-glide capabilities, including the Hypersonic Technology Vehicle concept,” said Maj. Gen. David Scott, the service’s operational requirements chief.

Scott said the concept of a conventional weapon that can strike anywhere on Earth in 30 to 40 minutes is still being developed.

“CPGS is something we are still figuring out with AT&L,” or the office of the defense undersecretary for acquisition, technology and logistics, he said.

Scott said the weapon will not be a Trident missile with a conventional warhead, as he had seemed to suggest in a an earlier interview. The Trident is a submarine-launched intercontinental ballistic missile (ICBM) that is armed with a nuclear warhead.

Oh, and technically, the Trident’s a sea-launched ballistic missile (SLBM) not an ICBM. Although, I suppose it would become an ICBM if it were used by the Air Force.