The Falcon is coming, hypersonic attack from the US
Based on "allied" refusals to allow US military forces access to their air bases and air space over the past decades, US military planners are now preparing to go it alone, in a “friendless” environment, if that's what's required. Considerable research and development have been underway to enable US air forces to attack multiple targets almost anywhere on Earth from the US in less than two hours using unmanned and remotely controlled hypersonic aircraft, aircraft that can be recalled if required. The "need for speed" is paramount; fast response is the by-word. This in turn will enable us to substantially reduce our reliance on overseas airfields and bases. This evolution supports our long-held desire to bring our military forces home, except those afloat, and employ our advanced technologies to defend the homeland from the homeland. One defense expert says this capability will be able "...to crush someone anywhere in the world on 30 minutes' notice with no need for a nearby air base."
June 27, 2013 addendum
The USAF’s X-51A Waverider reached Mach 5, nearly 4,000 mph, flying for three minutes employing an air-breathing engine on May 1, 2013. The previous test flight in May 2010 employed a combustion engine. So this latest test was the first and longest flight for the air-breathing design. Such a design does not require it carry a heavy load of oxygen and therefore makes the vehicle much lighter. NASA’s X-43A scramjet holds the world’s record for a jet-powered aircraft, flying Mach 9.6 or nearly 7,000 mph.
May 28, 2010 addendum:
July 3, 2009 addendum:
The first X-51A scramjet engine demonstrator vehicle, shown here, arrived at Edwards AFB, California, June 25, 2009. It is a static test unit that will be used in ground testing starting July 6, 2009, in preparation for the first X-51A flight test that is slated for late October 2009 off of the southern California coast. The X-51A is an Air Force Research Lab-led effort to demonstrate air breathing hypersonic propulsion using a supersonic combustion ramjet. Photo credit: Mike Cassidy
December 1, 2007 addendum:
At an advanced high-speed test in the New Mexico desert November 26, 2007 Boeing Phantom Works and the U.S. Air Force Research Laboratory began attempting to solve the problem of safely releasing ordnance from inside an airframe traveling at high supersonic speeds. The test is a small but potentially significant step in the Pentagon's development of a capability to strike anywhere in the world on short notice. Here's the challenge: ordnance released from an internal weapons bay at sufficiently high speeds will be forced back up into the bay by the airflow beneath the aircraft. The engineers are trying to develop a way to manipulate airflow actively to release munitions safely at higher supersonic speeds. The recent test, done on the ground, was successful, a good start.
March 21, 2005 (original article)
The vital national interests of the United States are no longer always in synch with those of its so-called allies. It has been this way for several decades. So-called American allies, most notably European NATO allies, have repeatedly refused the US access to or use of their bases and airspace when the US has wanted to conduct military operations. It has long been recognized by American military strategists that the US must substantially reduce its reliance on overseas bases and airspace. Air-to-air refueling has been a major outgrowth of this. But new technologies are now available to reduce American reliance on forward basing even more, substantially more.
The Falcon Program is a giant step in this direction. This is a research and development program of the joint Defense Advanced Research Projects Agency (DARPA) and the USAF. The goal is to develop and validate, in-flight, hypersonic technologies that will enable prompt global reach missions and demonstrate affordable and responsive spacelift. FALCON, a name held dear to many Air Force hearts, is a handy acronym for Force Application and Launch from CONUS (Continental United States).
Eric Daniel, writing for Military.com, hits the nail on the head:
“FALCON would give the United States a global prompt strike capability by using hypersonic sub-orbital launch platforms to deliver rocket powered sub-munitions to the target area, as far as 9,000 miles away … The issue here is response time. In the event that America should ever find itself both at war and completely friendless, we must either wait until the enemy fleets arrive or we must take the fight to the enemy from right here in the US.”
DARPA has said: "This capability would free the US military from reliance on forward basing to enable it to react promptly and decisively to destabilizing or threatening actions by hostile countries and terrorist organizations."
A smart journalist for the BBC said it this way: "The US will be able, using aircraft based on its own territory, to strike at individual targets without warning and without the need for foreign bases."
John E. Pike, director of GlobalSecurity.org, a nongovernmental defense think tank, said that the program will allow the United States: "...to crush someone anywhere in the world on 30 minutes' notice with no need for a nearby air base."
You could stop your reading here and ponder the implications of those words for weeks. The implications are significant, very significant indeed.
But let's get on to the hardware, and where it stands.
Broadly speaking, there are major pieces of hardware involved.
First, an unmanned, reusable vehicle that can use conventional military runways in the US and carry a 12,000-pound payload to a target 9,000 miles away in less than two hours. This vehicle is being called a Hypersonic Technology Vehicle (HTV). The HTV would get to its target, wherever it is, in less than two hours, traveling at speeds up to perhaps Mach 10, and it might return to base back in the US at Mach 3-4. It would be available for rapid turn-around and another mission. unlike an Intercontinental Ballistic Missile (ICBM), this vehicle can be recalled prior to striking its target(s).
The second suite of hardware consists of the munitions that will be carried and dispensed by the HTV. The requirement at present is for the HTV to carry a 12,000-pound payload. This payload can come in a variety of configurations, including nuclear warheads, small diameter bombs, cruise missiles, cluster bombs, bunker busters etc. Perhaps what is most intriguing about the newly emerging concept is something called the Common Aero Vehicle, or CAV. the CAV itself is vehicle, a hypersonic glide vehicle. It is unpowered, but maneuverable, and it may or may not have "wings." At present, the thought is that a single CAV would carry 1,000 pounds in munitions. A single HTV might release 8-10 of these CAVs, each of which would be directed at a different target, and the CAV itself could be used as a bunker buster, striking its target at above Mach 5, which would create kinetic energy some 60 times greater than a vehicle hitting its target at Mach. The CAV might reenter the atmosphere from near-space at speeds up to Mach 25, and slow down because of the atmosphere to perhaps Mach 8-10.
The third piece of hardware associated with Falcon is the Small Launch Vehicle (SLV). The objective is for the SLV to place small satellites into orbit, such as reconnaissance, communications and navigation satellites, virtually on demand, also at hypersonic speeds. We wish to underline "on demand." One can envision a small special forces team on the ground in a foreign land searching for a particular target. The team believes it spots the target, and requests a reconnaissance satellite be launched to confirm it, accurately locate it, and size it for weaponeering definition. The SLV launches the satellite a very short time later, the satellite does its work, and a HTV-CAV system is launched and destroys the target, all within a matter of hours.
The SLV vehicle, the simpler vehicle, will validate the hypersonic concept and is to be ready by 2010. The HTV and CAV are to be ready by 2025.
Imbedded in all of this is the requirement for the US to obtain and maintain space superiority. Achieving space superiority demands rapid response, quick turnaround, and high on-orbit maneuverability. Therefore, in addition to all we've discussed, launch on-demand hypersonic attack vehicles might be required to knock down space targets that could interfere with the overall attack mission on the ground.
The US is using and will increase using the realm of space to fight here on Earth, and in space. Therefore, achieving and maintaining space superiority is crucial.
We've thrown around some Mach numbers and need to gfve you a sense for their meaning. Mach equals the speed of sound. Mach 7 consisting of remote controlled missiles, called Common Aero Vehicles (CAVs), small diameter bombs, cruise missiles or other munitions, including penetration ordnance and a nuclear payload, and get . This means we could fly virtually between any two points on the globe in less than two hours. These missiles would be hypersonic gliders carrying up to 1,000 pounds of bombs or other payload to an intended target. The aircraft are to be quick turn-around capable and they can be recalled before the target is attacked. The aircraft would be unmanned.
It is expected the aircraft would reach speeds of Mach 7 or more. It is expected that the speeds to target would far exceed the return to base speeds.
means seven times the speed of sound. Hypersonic is considered to be anything above Mach 5
Flying a commercial jet takes you to about 0.8 Mach. Fast military fighter jets can fly at Mach 2.
The SR-71, our fastest jet, a manned aircraft, flies at Mach 3.5. The Concorde could do up to Mach 2.
The fastest manned rocketplane we have built was the X-15, also manned, and it achieved Mach 6.6 in 1960.
Unmanned Russian jets have achieved Mach 6.4.
The scramjet is the key enabling technology for hypersonic flight. This is a nickname for "supersonic combustion ramjet." It is a ramjet engine designed for hypersonic flight speeds.
There are four basic types of air-breathing engines: the turbojet, the turboprop, the turbofan, and the ramjet. There are good graphics and easy-to-understand explanations of them at K-8 Aeronautics Textbook.
We will focus on the ramjet, and then one not mentioned by the Aeronautics Textbook, the scramjet.
Ramjet schematic, presented by K-8 Aeronautics Textbook
Most of us are used to jet engines that have a lot of moving parts inside, like compressors, turbines or fans. The ramjet and scramjet have no moving parts.
The ramjet uses a "jet" of air for thrust. Air is drawn in at the front and compressed. Fuel is then added and the resulting mixture is combusted. The combustion greatly increases the volume of the gases which are then exhausted out of the rear of the engine, and hence you get thrust.
Pratt & Whitney 200 engine used on the F-16 fighter, graphic presented by avitop.com
Unlike those jet engines with moving parts, such as the PW-200 shown above, the ramjet must be powered by another engine to supersonic speeds to get that air drawn it needs to work. Jet fighters and commercial jets use turbines and fans to produce the initial air needed to get going. The PW200 above is a turbofan with afterburner capability. It is virtually self-sufficient; you start the engine electrically, the turbofans start turning, and they suck in the air needed to create thrust. The ramjet on the other hand needs something like another aircraft or missile to launch it to a desired speed, after which it is dropped into its own free flight, air starts flowing into the engine at very high, even supersonic speeds, there is combustion that produces the gases needed to provide it forward thrust, and it heads out on its own to even faster speeds.
The ramjet inlet must slow the air flow from supersonic speeds to a subsonic speed for ignition in the burner. Above about Mach 6.0, the velocity of the air flowing into the ramjet burner is so high that combustion cannot be completed, and the necessary exhaust velocity will be barely greater than the original velocity. Not enough thrust will be generated for the required performance. Therefore, it is not useful for hypersonic flight.
As a result, the scramjet or supersonic combustion ramjet was developed.
Scramjet schematic, presented by Imperial College of London
Instead of slowing the air flow down to subsonic speeds for combustion, the scramjet will have combustion take place while the air stream is still supersonic. The design of a scramjet requires extremely high speed airflow to function. It therefore also requires acceleration to supersonic speed before it can be started. The fuel used tends to be hydrogen gas.
Miss F. Ning at the Imperial College of London provides a fairly understandable explanation of the difference between a ramjet and a scramjet:
"A scramjet is an air-breathing engine that can operate from Mach 5-6 up to at least Mach 15. As NASA puts it, 'A scramjet (supersonic combustion ramjet) is a ramjet engine in which the airflow through the whole engine remains supersonic.' The best way to describe scramjet is to compare it with Ramjet, its lower speed equivalent. A ramjet engine provides high-speed propulsion and has existed for years. It has no moving parts but achieves compression of intake air by the forward velocity of the vehicle. Upon entering the inlet, air is slowed by aerodynamic diffusion created by the fuel injector and dynamic pressure is converted into high static pressure. The fuel used here is generally hydrogen. After the fuel injection, hot air mixes with the fuel and expands at a high speed in the combustion chamber. Then the air passes through a nozzle which accelerates the exhaust air to a velocity much larger than that at the inlet, thus creates thrust.
"Above Mach 5, ramjet becomes very inefficient: there is a high temperature increase at the inlet which would ionize the intake air. This process absorbs energy from the burning of fuel. Also the inlet has to decelerate the air from high supersonic speeds to subsonic to enter the combustion chamber, resulting in a large amount of pressure loss. Both phenomena greatly reduce the efficiency. The main difference between scramjet and ramjet, as the name suggests, is that the air flow exiting the inlet of a scramjet is at supersonic speed and avoids the air being ionized as well as temperature increase. Also, it burns fuel in a stream of air at supersonic velocities, incurring less pressure losses compared to a ramjet at the same intake velocity."
NASA X-43 artist's concept, presented by NASA
NASA has already built and flown the X-43, designed to use a scramjet to fly at Mach 10, or about 7,381 miles per hour.
Here you see the X-43 vehicle up front, attached to a Pegasus rocket, which accounts for most of the hardware hanging from the wing of a B-52. Photo presented by NASA.
In this photo, the Pegasus with X-43 attached has been dropped from the B-52 at an altitude of 40,000 ft, and here you see the Pegasus rocket ignite. It took the X-43 to the desired speed and altitude, then dropped it, and it ignited and flew to nearly Mach 10. Photo presented by NASA.
In November 2004, the X-43A research vehicle demonstrated an air-breathing engine can fly at nearly 10 times the speed of sound. Preliminary data from the scramjet-powered research vehicle show its revolutionary engine worked successfully at nearly Mach 9.8, or 7,000 mph, as it flew at about 110,000 feet. It was attached to the Pegasus booster rocket engine and dropped from 40,000 ft, by a NASA B-52. Once dropped, the Pegasus rocket boosted it to the desired altitude, at which time Pegasus broke away and the X-43's scramjet ignited and powered the aircraft to its Mach 9.8 speed. The flight took place in restricted airspace over the Pacific Ocean northwest of Los Angeles.
The US has already operationally employed unmanned aerial vehicles in combat including the Predator and Global Hawk, with enormous success. The days of sayin "no" to unmanned flight are over.
Predator B unmanned aerial vehicle, presented by NASA
Global Hawk unmanned aerial vehicle, presented by the Department of Defense
These aircraft can reconnoiter and attack targets and can fly for 36 continuous hours with a range of 13,500 miles. They have been terrific combat tools, but they are not fast enough.
The Air Force in particular is after a capability to strike numerous targets around the globe from bases in the US within just a few hours of launch. We will emphasize again that US defense planners are acutely aware of our military reliance on allied and overseas bases. This reliance has taken an operational toll on US forces, has cost the American taxpayer a great deal of money, has allowed many allies to enjoy the bierstübe instead of paying for their own defense, and has earned us little respect in return. So that party is coming to an end.
C-5 Galaxy, June 1970. The C5 was a workhorse during the Yom Kippur War. It had an air-to-air refueling capability, but it was not used because of other technical problems at the time with the aircraft. The C-141A, a smaller strategic transport, did not have such a capability. Photo credit: U.S. Air Force
This editor recalls the 1973 Yom Kippur War, when Syria and Egypt attacked Israeli forces in the Sinai and on the Golan Heights. The US decided to support Israel and ordered USAF C5 and C141 transports to fly logistics missions from the east coast of the US to Lod Airport in Tel Aviv. This was known as Operation Nickel Grass. Most European countries denied the US overflight and landing rights if carrying cargo bound for Israel. Portugal at the 11th hour finally agreed to let them land at Lajes Air Base, Azores. USAF aircraft were already on their way to that airfield when approval came. The airlift lasted 32 days.
Many USAF aircraft literally landed at Tel Aviv from the Azores on fumes. The transports had to fly from Lajes through the Straits of Gibraltar, careful not to overfly any European or Arab country while passing through, and then even Greece demanded they fly south of Crete rather than a better route close to and just north of Crete. There could be no missed approaches for them at Lod. In addition, the US Navy fleet had to provide combat air patrol, search and rescue, navigation diversion and other support as needed during the flight over the Mediterranean Sea. It remains unclear where transports in distress could have landed. Israeli flew fighter aircraft 150 miles out over the Mediterranean Sea to escort the transports in.
The major outcome of this experience for the US was to outfit its transports with an air-to-air refueling capability, so airlifters would not require forward bases. It was obvious in 1973 we could not count on allied support, especially from the Europeans. For several decades the US protected Western Europe from the Soviet Union. It is arguable what the US has received from the Europeans in return.
We have seen over and over since that time, most recently in the Iraq War, that we cannot count on our allies to help us protect our vital national security interests. Therefore the kinds of programs like Falcon emerge. Americans should support these and urge they be accelerated as fast as technologies and engineering will permit.
As indicated previously, response time is of the essence. Once a reconnaissance vehicle or agent on the ground has located a high value target, such as individuals or specific pieces of military hardware, military commanders need to get a weapon on the target as rapidly as possible, before they move. Falcon will allow us to do that from the US or from forces afloat.
When you take a look at Falcon, you get introduced to a host of related systems that are in the works in one form or another. We thought you might enjoy looking at some of these. For those of you young enough to dream, this is a tremendous field of professional endeavor for you to pursue as you march through school and university.
This entire endeavor should make you proud --- our people are thinking ahead, and our people are bringing their very best technical and design talents to the table. Our enemies need to understand we are not fooling around.
According to DARPA:
"The intent is to hold adversary vital interests at risk at all times, counter anti-access threats, serve as a halt-phase shock force and conduct suppression of enemy air-defence and lethal strike missions as part of integrated strategic campaigns in the 21st Century."
Supersonic combustion ramjet technology being developed under the Air Force Research Laboratory's HyTech program will enable missiles to fly at speeds up to Mach 8. Such conceptual missiles like the one pictured could fly hundreds of miles in minutes to defeat time-critical targets. Credit: Mike Bruggeman, Air Force Research Laboratory's HyTech program, presented by space.com
This is yet another artist's concept for the Falcon. As development matures, the look is likely to adjust. Graphic presented by Air Force Magazine.
This image is illustrating Hyper-X flight Trajectory, showing Research Vehicie alone after separation from Pegasus Booster. Graphic presented by NASA.
Another view of Hyper-X, an illustration, presented by NASA.
You might recall SpaceshipOne. It is a commercial manned vehicle, launched for outer space on schedule on June 21, 2004. The goal was to achieve altitude 62 miles and return, and she did it! The flight marked the first time that a non-government spacecraft reached the altitude considered to be the boundary between Earth's atmosphere and outer space. We remind of you this for two reasons. First, the Falcon concept is not "vaporware." There are plenty of technologies now in full R&D and some systems that have flown to take you down the path to Falcon. Second, and underscoring the first point, Environmental Aeroscience Co., eAc, designed and tested a new nitrous/HTPB hybrid propulsion system specifically for SpaceShipOne, and eAc is participating in Falcon.
This photo shows the eAc propulsion system in its test configuration for SpaceShipOne. Photo presented by eAc.
In our story, we mentioned a "scramjet." This is one developed for the Air Force by Pratt & Whitney. It has had its sidewall removed. This engine has been ground-tested demonstrating performance at Mach 6.5. Incredibly, it is about six inches wide and 75 inches long. All together, these test results marked a major milestone. This kind of technology will enable Falcon development. Photo presented by Air Force research Lab (AFRL)
This is the Hystrike hypersonic missile, scheduled to be operational between 2005-2012. It's wingless, but has a "U-joint" mechanism that will allow it to change course by bending. The goal is a single hypersonic strike weapon that will be launchable from air, surface and subsurface platforms, one that will produce substantially decreased time-to-target. This is meant to be a bunker buster, traveling at Mach 8 or more, it will produce kinetic energy 64 times greater than a weapon traveling at Mach. This kind of technology will contribute to Falcon's development. Photo presented by globalsecurity.org
Meet HyFly, a hypersonic sramjet missile demonstrator. Boeing got the contract in 2002. HyFly's objective is to mature the dual combustion, ramjet-based, hypersonic strike missile concept. In 2002, the first-ever successful test of a full-scale, fully integrated, liquid hydrocarbon fueled dual combustion ramjet engine was accomplished. The engine tested at Mach 6.5. This kind of technology will contribute to Falcon's development. Graphic presented by Aerojet and photo presented by Office of Naval Research.
A Joint Unmanned Combat Air Systems (J-UACS) program is being conducted by DARPA-USAF-USN to demonstrate the technical feasibility, military utility and operational value of a networked system of high performance, weaponized unmanned air vehicles to effectively and affordably prosecute 21st century combat missions, including Suppression of Enemy Air Defenses (SEAD); Electronic Attack (EA); precision strike; surveillance/reconnaissance; and, persistent global attack within the emerging global command and control architecture. The J-UCAS vision is for a lethal, unmanned system-of-systems that expands mission options and provides revolutionary new capabilities for air power projection into deep, denied enemy territory and other extremely dangerous adversary domains. The program is presently exploring two families of capabilities, the Boeing (X-45 family) and Northrop Grumman (X-47 family).
An artist's impression of the Slender Hypersonic Aerothermodynamic Research Probe (SHARP) flight vehicle. This craft is part of a program to test ultrahigh-temperature ceramic materials for sharp leading edges. Two SHARP vehicles have already flown, one with a sharp pointed nose and the other with sharp "fins". The proposed vehicle pictured here will test high-temperature materials in a more complete vehicle configuration. Text and graphics presented by physicsweb.org, courtesy of NASA.