Pentagon Bomber Evolution Underway

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Pentagon Bomber Evolution Underway | AVIATION WEEK

The latest analysis of future long-range strike needs by the Pentagon will be submitted in time for its recommendations to be reflected in the Fiscal 2012 budget.

Few people, least of all advocates of an active, nonvintage bomber fleet, expect exciting news. Service-centric politics, a joint-service construct under which ground forces heavily influence the study and pressure on procurement budgets (from overruns in the Joint Strike Fighter program) will result in modest recommendations.

The most likely include the endorsement of a long-range, nonnuclear ballistic missile capability, although the time*scale and budget remain uncertain. The conventional prompt global strike (CPGS) concept is a favorite of Marine Corps Gen. James Cartwright, vice chairman of the Joint Chiefs.

Expect some backing but little money for two other concepts: a joint-service, long-range cruise missile, launched from Virginia-class submarines and B-52s, and the Navy's Unmanned Combat Air Vehicle (UCAV-N), which may be termed a means of extending the range of a carrier air group. Both systems may be linked to another joint-service study defining a future "air-sea battle" and focused on matching China's growing power in the Western Pacific.

As for a future USAF bomber, conventional wisdom—i.e., views acceptable to Cartwright and Defense Secretary Robert Gates—is that the idea merits study, over and above several dozen studies carried out in the past decade. In June, Lt. Gen. Philip Breedlove, Air Force deputy chief of staff for operations, plans and requirements, was quoted as saying the word "bomber" can no longer be spoken in the Pentagon and requirements "trickling down from the highest levels" call for a much smaller aircraft. Some sources believe Cartwright is pushing the idea of a USAF variant of UCAV-N.

Air Force Chief of Staff Gen. Norton Schwartz and Secretary Michael Donley have not taken up the cause of a new bomber. The only four-star to support the bomber has been Strategic Command leader Gen. Kevin Chilton.

With little high-level support, bomber advocates are doing what they have done before: changing the name to "reconnaissance-strike." Lt. Gen. David Deptula, in his last press briefing before retirement, reiterated his view that intelligence, surveillance and reconnaissance (ISR) and attack missions are no longer separate. A penetrating ISR platform that cannot be armed makes little sense.

Industry and service studies of a new ISR and strike platform appear to be converging, driven by technological developments, likely operational requirements and fiscal realism.

Technologically, one factor that has arisen in the past few years is the successful demonstration of extremely low-observable (ELO) technology, with wideband, all-aspect signature reductions of -40 to -50 dB. or more, under one or more covert test programs. One step in this process may have been Boeing's Bird of Prey demonstrator, with a radar cross section (RCS) so small that visual signatures became dominant. A consultant on that project was stealth pioneer Denys Overholser, who has been involved with projects envisioning RCS levels to -70 dB.—the size of a mosquito.

ELO mandates an all-wing or blended-wing body and tailless, subsonic configuration with buried engines. Advances in the computational analysis of the complicated airflows over such shapes improve aerodynamic efficiency and permit simpler inlet and exhaust systems, putting unrefueled ranges of 5,000 nm. within reach for a "demi-B-2"-sized aircraft. Northrop Grumman mentions an unrefueled range of 5,600 nm. for UCAV-N, with new engines based on advanced commercial cores.

The demonstration of reliable, long-endurance, autonomous operations is important. Many bomber advocates agree that a new ISR/strike aircraft should be optionally piloted. If it acquires a nuclear mission, a crew is likely to be mandatory, and crewing would ease mixed-use airspace concerns. On the other hand, the aircraft would be inherently capable of operations beyond human endurance, and an unmanned mode could avoid sending crews beyond the reach of search-and-rescue assets.

Northrop Grumman concepts for an advanced unmanned ISR/strike system list a range of autonomous functions—threat awareness and avoidance, electronic and lethal countermeasures, and cooperative defense. Onboard sensor fusion and target recognition would be combined with the ability to match imagery with terrain, passing high-grade target information to other assets.

Bomber advocates are monitoring laser weapons in the 100-kw.-class, considered adequate to kill an incoming missile. Combined with ELO, this could give a bomber the ability to survive against current and projected threats.

A survivable aircraft with a large and diverse payload has advantages. It can prosecute targets of uncertain location, and its range is a hedge against antiaccess and area-denial strategies. Unlike the smaller UCAV, it carries a mix of weapons.

The biggest challenge to the bomber is price. Procurement cost in the $500-million range is likely, equivalent to 4-5 JSFs, but carrying 4-5 times the warload five times farther. The total investment in a force of 100 new bombers would be about the same as the cost of replacing Trident submarines. But, as enthusiasts suggest, the bombers would deliver similar or greater longevity and more flexibility.

 

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I am with The conventional prompt global strike (CPGS) concept -

Prompt Global Strike Program

The program under which Washington is developing its prompt response strategy is called Prompt Global Strike or alternately referred to as Conventional Prompt Global Strike. This capability could be based on a triad of three technology systems:-

* Trident Submarine Launched Ballistic Missiles
* Hypersonic Cruise Missiles (Air launched/mounted on Minuteman ICBMs (eg. Air Force A-51). The Hypersonic technology vehicle program is managed by DARPA, the conventional strike Missile Program by US Air Force Space and Missile Centre and the Advanced Hypersonic Weapons Program by the Army Space and Missile Defense Command respectively.
* Super Stealthy Strategic Bombers able to avoid detection by radar and thus evade ground to air defences.
* Orbital Global Strike Systems. In addition to the above three options that are being developed there is the option of Orbital Strike Systems.These would be placed in earth's orbit and strike anywhere on the Globe in less than an hour.

The PGS Philosophy

The ambitious aim of this program is to be able to field a system capable of a high precision conventional weapon strike, anywhere across the world in just one hour. Such a PGS system, said US Gen James Cart Wright, would complement the forward deployed Forces of the US. These include:-

* The Air Expeditionary Forces These could be deployed within 48 hours.
* Carrier Battle Groups These can respond within 96 hours.

Thus today, unless you want to go nuclear, response times are usually measured in days, maybe weeks, till the military can respond with regular forces. The complexity of the existing security environment and enhanced RSTA (Reconnaissance, Surveillance and Target Acquisition) capabilities can generate situations, which calls for an urgent response that is measured in minutes. That is the basis of the US quest for a PGS system. However, the critical factor is that such a strike system presupposes the ability to acquire and transmit intelligence at such high speeds. On 28 Aug 1998, Osama Bin Laden had been located in Eastern Afghanistan. By the time he was targeted with cruise Tomahawk missiles, fired by the USS Abraham Lincoln Carrier Battle Group, he had already left that cave complex. With a top speed of 550 mph, the Cruise Missiles had taken two hours to do the 1,100 mile trip to the target area. It had missed Laden reportedly by less than half an hour. Keeping these performance parameters in view, the US military had begun its quest for a PGS from 2001 Nuclear Posture Review onwards. In the Bush era, the emphasis was on a Trident Nuclear Submarine based system.

The Trident Solution

The respected science magazine,Popular Mechanics gave details of this system. In 1988, Lockheed Martin's Trident II D S Nuclear Ballistic Missiles entered service on Ohio Class submarines. In the PGS system, each submarine would be armed with 22 Tridents along with two retrofitted Trident missiles, each with four independently targetable conventional warheads. Gas pressure would eject the Trident from the submarine. Once the missile clears the water, the first stage ignites and burns in about 65 seconds. When the missile is locked on to targets at maximum range (roughly 6,000 nautical miles), this falls away. The second stage ignites for another 65 second burn that carries the missile 500-800 miles down range. The third stage now ignites for 40 seconds concluding the boost phase that lifts the Trident some 600 miles above the earth (the altitude of weather satellites). The post boost vehicle (or bus) now receives navigational updates and deploys four independently targetable warheads (that travel at 13,000 mph and have an accuracy of 30 ft). The warheads are GPS guided on decent by means of tiny flaps. Two types of warheads are planned:-

1. The Fragmentation version which shatters tungsten rods (each upto 12 times more destructive than a 50 caliber bullet). Anything within a 3,000 sq ft area is obliterated by this metallic storm.
2. The Bunker Busting version This has a bunker-busting metal "shock-impactor", which relies on kinetic energy for its destructive power. This can tackle targets in deep cover/underground bunkers or caves.

The problem with this solution began with the strident response of the Russians and the Chinese. They warned that they would not be able to distinguish between the launch of such Trident missiles that were armed with nuclear/conventional warheads. This could trigger off accidental nuclear responses and result in a nuclear holocaust. Apparently the US Congress was thus alarmed enough to cancel funding for this program.

The Boeing XM-51 Hypersonic Wave Rider Program

The other programme in the PGS capability envelope is the Hypersonic Cruise Missile like the Boeing XM-51 missile. This missile is carried upto 45,000 ft by a B-52 bomber or a fighter jet. A rear mounted Army Tactical Missile System rocket kick-fires it to propel the 1,800 pound missile to Mach 4.5 and 100,000 ft. The rocket then drops away and the XM-51's engine takes over. The shock waves produced by the hypersonic speeds open the internal inlet and compress the air. The compressed air mixes with JP-7 jet fuel and is ignited. This scram jet then pushes the missile to Mach 5 speeds (3,000 mph). In tests in the USA, Mach 10 (7,000 mph) speeds have already been achieved. A flight from Arabian Sea to Southern Afghanistan at Mach 5 would take just 20 minutes to destroy a target with just its own kinetic energy.

Minute Man Mounted Hypersonic Missile

Conventional bombers, says Gen James O'Cartwright, are however too slow and too intrusive for many global strike missions. Hence, as of 2010, the US Air Force is fielding a prototype modified Minuteman III ICBM with a maneuverable conventional warhead. This could even be a Hypersonic Cruise Missile. It is said that US$ 12 million were appropriated for this Conventional Ballistic Missile Program in 2007. However, once again the primary complication is based on the Ambiguity problem- how do the Russians/Chinese distinguish between a conventional/nuclear warhead armed ICBM? Various bizarre solutions have been suggested, eg. Keep the missile trajectory low so that it remains within the atmosphere. The second is to have separate launch sites for such conventional armed nuclear missiles, which the Russians and Chinese would be periodically allowed to inspect. Both the Russians and Chinese have highlighted strong chances of triggering off an accidental nuclear war with such conventional weapons.

However, on 11 April 2010, US Secretary of defense, Robert Gates indicated that the US already has a global strike capability. This could be based on the Trident system that was repeatedly shelved earlier. The hypersonic cruise missiles would be ready by 2015 and the Minuteman based conventional warhead by 2017 or so. Rick Rozoff reports that the Obama administration has requested US$ 239.9 million for a prompt Global Strike System across the military services in fiscal 2011. At this rate, the Pentagon would have spent some US$ 2 bn on PGS by the end of Fiscal Year 2015.

Conclusion

To conclude, the Prompt Global Strike (PGS) program aims at enabling the United States to plan and deliver military strikes anywhere on the globe in less than one hour. In technical terms, It aims to provide the US President with the ability to plan and deliver, limited duration and extended range strikes anywhere on the globe in less than one hour. The 2001 Nuclear Posture Review (NPR) formally introduced the global strike concept as part of a new triad that integrates conventional and nuclear force options into an offensive strike capability suited for the 21st Century. Gen Cartwright, the former Commander of the US Strategic Command had agreed in a 2006 congressional hearing that a PGS capability is necessary because, "it is unlikely that we will have forces in every place we need them at the crucial moment, when we have an opportunity to stop a WMD armed threat far from our shores." The anchor premise that underlies the PGS concept therefore is based on two critical assumptions:-

* That elusive threats to national security can suddenly emerge (to include WMD threats by rogue states/non-state actors).
* The US must possess the capability to strike rapidly without relying on existing forward bases. These can respond in 48 to 96 hours or more, which is simply not good enough to deal with the new order of threats.

The primary concern of the US Congress in sanctioning funds for such PGS program is the Ambiguity problem or the fear of triggering off of an accidental nuclear war because of the inability of the other countries to distinguish between the launch of conventional/nuclear warhead tipped Trident or Minuteman Missiles. This is the current grey area in the PGS revolution that now seems around the corner. It seeks to reduce reliance on nuclear capabilities by creating equally responsive and destructive conventional military capabilities, which can respond within minutes to the significant intelligence, eg. Impending terrorist WMD threat/rogue state missile attack). However, such capabilities could equally provide the means to destroy/disable conventional air defense systems in sudden surprise attacks that set the stage for a more conventional invasion of an adversarial State. We are now looking at a whole new order of possibilities.

India has made impressive strides in the field of rocket science, missile capabilities and telemetry. We need to carefully study the technological advances now opening up in this field. These have graduated beyond science fiction and could be concrete capabilities by as early as 2015, if not earlier. In the face of repeated mass casualty terrorist strikes on our major population centres, do we need such a capability? What would be its impact in a conventional war scenario? Would it enable a crippling Counter- Force strike or a sudden crippling attack on our Command and Control centres and air-defense assets? These are critical aspects for study and analysis.

Conventional Prompt Global Strike System