In today's environment, some 70 percent of all
research is now conducted within a "commercial" framework
outside the United States and is thus readily available to likely
adversaries. In terms of sheer size, several economies (Japan, China, and
the European Union, for example) are approaching the magnitude of ours,
and may even exceed it. Moreover, inexpensive, highly-motivational,
web-based distance learning on demand promises to greatly accelerate these
trends. With respect to techniques and materiel, the Info/Bio/Nano-technology
revolution(s) are providing:
- Increasingly small, ubiquitous,
inexpensive, networked, scientific and commercial,
land-, sea-, air-, and space-based sensors
applying multiple physics and hyper-spectral techniques
- Robotics and automation "in the
large"
- Long-range precision strike
- Inexpensive mini/micro/nano"everything,"
including platforms, sensors, and weapons
- Wholly new classes of biological
weaponry
- Hard-to-jam optical communication and
navigation systems
- Greatly enhanced explosives and
"volumetric" munitions... and finally,
- A fourth "weapon of mass
destruction" in the form of physical or electronic
information operations (IO)
Current estimates indicate that over the
next 25 years, computing will increase in speed by some six orders of
magnitude, and communication speeds will increase by four orders of
magnitude as optical systems replace microwaves. Further, the use of large
active-volume or broad-area techniques and advanced energetic materials in
weaponry will increase their destructive power by up to four orders of
magnitude.
The "Slingatron" launcher
offers the potential for rapid-fire intercontental bombardment
using advanced boost-glide vehicles and unconventional payloads. |
The overall impacts of these
largely-commercial and globally-available capabilities on the outlook for
military operations are far-reaching. In particular, these technologies
will enable much more effective "warfare on the cheap," in which
"peer competitors" are no longer defined by their possession of
megatons of Industrial Age artifacts in steel and aluminum. They create
dangerous implications for any attempt to carry late-20th century U.S.
power-projection concepts into the 21st century. Numerous systems are
emerging that could be used in tandem to wreak havoc on U.S. air and
sea-surface logistic and strike platforms, both en route and in the
operational theater. Non-stealth and undefended logistics platforms are
particularly at risk. What will be "new" in this future threat
environment are the omnipresent, omniscient sensor suites mentioned
previously and the sheer number and variety of long-range and
pre-positioned precision munitions that can be brought to bear. Unless
platforms and weapons enjoy the sanctuary of the deep ocean, being
targeted will be a "given" in the out-years. New age weapons and
munitions will include:
- Lurking, semi-submerged, anti-air or
anti-surface missiles in the water column, with off-board targeting by
netted sensor "webs"
- Transoceanic unmanned underwater and air
vehicles (UUVs and UAVs)
- "Brilliant" mines
- Long-range cruise and theater ballistic
missiles
- Very long-range "guns," using
Blast-wave Accelerator and Slingatron technology
Just consider the last. The Blast-wave
Accelerator was analyzed at the University of Texas/Austin by Professor
Dennis Wilson and is under study by both the Army and NASA for inexpensive
access to space. The concept involves sequential detonation of charges
behind a projectile (without a barrel) yielding ICBM or IRBM speeds after
only 100 to 200 feet of acceleration. Essentially this is a
"rocket" in which the external structure and propellant never
leave the launcher - only the warhead. The latter could be proected in
flight by a technique test-flown by NASA in the 1960s at 18,000 to 25,000
feet per second - injection from the nose of a thin stream of liquid
water, which can be thrust-vectored. The 1,000-pound projectile would
operate in a boost-glide, vice ballistic, trajectory and offer not only
stealthy launch - no plume - but also exceptional flexibility,
affordability, and survivability, while retaining the ability to be
recalled. The Slingatron, also being studied for inexpensive space access,
would use an oscillating horizontal tube - much like a
"hula-hoop" - to accelerate projectiles in a spiral path until
launch velocity is reached. Such an arrangement appears capable of lofting
hundreds to thousands per minute of ten-kilogram projectiles over even
intercontinental ranges.
As an example of progress in unmanned aerial vehicles (UAVs), the
University of Washington recently flew a UAV across the Atlantic on only
1.5 gallons of fuel and intends to make a trans-Pacific attempt next.
Increased precision, along with technology advances in materials, are also
enabling a "mini-ICBM" option with terminal guidance for
mid-ocean strike. Another potentially potent innovation is the Vortex
Combustor under development at Penn State's Applied Research Laboratory,
which burns nanoscale aluminum particulates and sea-water to provide
inexpensive air-independent propulsion (AIP) for both submarines and very
long range UUVs.
One way for the
"Enemy-After-Next" to defeat or deter U.S. power projection with
relatively little expenditure is to ensure that our forces do not
"arrive at the party." The notional weapons described above -
and others - are all based on enabling technologies already "in the
pipeline," and they will make crossing the ocean in the air or on the
surface like running the gauntlet. Attrition by enemy action could well
begin within the continental United States (CONUS) itself and then over
the continental shelf, since we typically deploy from a relatively small
number of ports and airfields, thus simplifying the pre-positioning of
smart, "pre-need," anti-air and anti-surface missiles and a
variety of mines. As we will discuss below, "kill" mechanisms
will probably not be restricted to high explosives.
The "density" of the threat will grow even more dangerous with
increasing proximity to enemy-held coastlines. This is the "area
denial" problem discussed for some time now by the Defense
Department's Office of Net Assessment, among others. Well before
mid-century, "country-sized" magazines may be available to loose
"hordes" of inexpensive, long-range precision weapons with
advanced warheads bearing a "devil's brew" of lethal components:
electromagnetic-pulse generators and radio frequency blankers, IW
payloads, mines, fuel/dust/air or other volumetric explosives,
chemical/biological/microwave anti-functionals and antipersonnel weaponry,
as well as carbon fibers and "blades."
In the face of such an onslaught, friendly platforms will be hard pressed
not to run out of "bullets" just defending themselves, thus
causing both unacceptable attrition and the defeat of strike or power
projection operations. Beam weapons are sometimes suggested as at least a
partial counter to such a threat scenario, but even these have multiple
and inexpensive counter-countermeasures available to an adversary. One
quickly concludes that late-20th century power-projection or forced entry
approaches could be gravely threatened by a determined opponent with
access to these new, generally-available technologies.
What, then, might be some alternatives? Possibilities include global-range
cruise missiles and exo-atmospheric precision-strike munitions, launched
directly from CONUS on conventional or miniature ICBMs, and hypersonic
boost-glide projectiles launched from the several types of global-reach
guns mentioned above. The latter could be far less expensive and far more
survivable than our current options for global precision strike - tanking
B-2s and steaming aircraft carriers. Obviously, many information
operations could also be prosecuted directly from CONUS.
For shorter time-of-flight munitions, a deep-water "arsenal"
submarine deploying various "swim-ins" or "pop-ups"
provides a survivable option. Deep-water standoff is necessary because of
the danger posed by multi-static, low-frequency active (LFA) acoustics and
increasing capabilities for sensing the many non-acoustic
"indiscretions" associated with submarines in shallow water.
These include hull detection by visual, lidar, infrared, or bioluminescent
means; sensing the underwater wake by perturbations in the pressure field;
and measuring salinity scars, chemical releases, internal and surface
waves, turbulence, magnetic effects, radar returns, and other phenomena.
In the context of swarms of inexpensive, omnipresent sensors, based on
multiple physics, and operated on a "take-a-vote" sensor-fusion
principle to minimize false alarms, survival of shallow-water submarines
appears problematical.

Because of increasing area-denial threat, "almost
spherical" arsenal submarines could well become our best
land-attack option. |
Deep-water arsenal
submarines would obviously need tremendous capabilities for loading out
munitions. Thus, as almost a reductio ad absurdum approach in
designing such platforms, "almost-spherical" configurations
should certainly be investigated.
This shape would yield several synergistic benefits, including minimum
wetted area and friction drag, plus the smallest structural weight for
increased depth capability. The serious pressure-drag issue with such a
shape could be ameliorated to yield very low overall drag by using a
fully-integrated "Goldschmied" pump-jet propulsion approach,
with thrust vectoring for control. In this configuration, the pump-jet
inlet provides potential flow "sinks" inside the body and should
convert the back of the pump-jet shroud into a stagnation region instead
of a stagnation point. For enhancing the affordability and survivability
of such volumetrically-efficient platforms, a number of ab initio
design features suggest themselves:
- Extreme automation for minimal crew size
- An on-board chemical plant for producing
drag- reducing polymer from phyto- and zoo-plankton sieved from the
power plant coolant intake
- Active acoustic masking to defeat LFA
- Inclusion of a replenishable,
burst-speed "afterburner" system - perhaps a hydrogen-oxygen
rocket as an adjunct to a down-sized main propulsion plant
- Manufacture of underwater platforms via
robotic/magnetically-steered, electron-beam, free-form fabrication -
essentially "virtual prototyping" of the final product
Admittedly, this concept submarine would be
very different from what might result from continuing with our current and
evolving design practice. However, along with affordability and
survivability, volumetric loadout is the major issue for power projection
from submerged platforms. An "almost-spherical," deep-water,
arsenal submarine would have sufficient volume for many of the design
options listed above; space for adjunct sensors, such as mini UAVs; and
large capacity for storing munitions.
Other design alternatives for providing additional volume - such as simply
"plugging" existing designs - have already been proffered. But
in the opinion of this author, the revolutionary design approach suggested
here has enough potential to warrant its inclusion in a design
"runoff" for a future, submerged, deep-water "arsenal
ship." It could well constitute the only survivable
"close-in" strike platform for assuring naval power projection
in the future.
Dennis M. Bushnell is the
Chief Scientist of NASA's Langley Research Center, Hampton, Virginia. He
hails originally from Westbrook, Connecticut, the hometown of David
Bushnell of Revolutionary War "Turtle" fame, and they share a
common ancestor in William Bushnell (1680-1733) of Saybrook, Connecticut.
He is a member of the National Academy of Engineering, a Fellow of the
AIAA, ASME, and the Royal Aeronautical Society and is the recipient of the
NASA medals for Outstanding Leadership and Exceptional Scientific
Achievement. |