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Stealth, lasers, satellite-based guidance, and endurance airframes
transformed the Air Force during the last two decades, and advances
in propulsion, directed energy, robotics, and information technology
will transform the service again over the next 20 years.
That is the view of Gen. Gregory S. Martin, head of Air Force Materiel
Command, which oversees USAF’s science and technology efforts.
Besides being the service’s top technologist, he has held a
number of key USAF acquisition and operational posts in his 34-year
career.
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| According to Gen. Gregory
Martin, USAF’s push for advanced technologies is creating
increased “tension” between operational desire and
technological capability. Above is a stealth transport concept. |
In an early fall interview with Air Force Magazine, Martin said
the Air Force is not spending enough to develop innovations that
will provide the service its future decisive edge. However, he added,
the funds that are available are being allocated in a balanced way.
Martin also observed that, while the pace of invention and innovation
is speeding up, the demand or “appetite” for new capabilities
is increasing even faster, creating an unhealthy “tension”
between requirements and the ability of technologists to fulfill
them.
“The technologies that give us the dominance that we have
today, [as compared to] where we were” in the Vietnam era “are
GPS [Global Positioning System], stealth, endurance airframes, and
laser technology,” Martin asserted.
The GPS constellation underpins precision attack. Martin pointed
out that it is not really a space system but an exquisite timing
mechanism “enabled by a space vehicle.” It is a system
that still holds “immense potential” for the military.
Stealth has given USAF “a solid way to present massive amounts
of firepower with acceptable risk,” he said.
While aircraft such as the manned U-2 could fly long distances
at high altitudes, the need for a human pilot was their limiting
factor, Martin said. Uninhabited vehicles such as the Global Hawk
and Predator “can do what man can’t do” by holding
a position for very long periods of time. This staring, persistent
presence over the battlefield has been “very important”
and will become more so, Martin said.
Lasers, he remarked, have not yet been used as weapons per se—the
Airborne Laser is still in development—but have yielded huge
advances as target designators, in communications, in laser gyros
for navigation, and in their application as optical readers. He
also noted that lasers “produced things of significance for
our military forces very quickly, within a decade” of their
invention.
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Charge Phasers, Mr. Sulu
Lasers and other forms of directed energy offer some of the
most promising technologies for future Air Force needs—not
just in weaponry but in sensors and communications. Their
big drawback is the power required to make them useful.
Directed energy is “inherently inefficient,” according
to Lt. Col. JoAnn L. Erno, power division director of the
Air Force Research Laboratory’s Propulsion Directorate.
When firing a laser, for example, “90 percent of the
energy is lost to heat,” she said.
To compensate, AFRL is working on small generators that can
provide a power source able to generate “megawatt range”
power for directed energy weapons. Although it had been hoped
that future engines for fighters and even large reconnaissance
platforms would be able to generate the necessary wattage
to electrically power directed energy weapons, none now in
the pipeline will be able to do so and still power all the
aircraft’s own organic needs.
The Airborne Laser generates its power using a chemical system
that would be too large and bulky to be practical as a weapon
on gunships or fighters.
Moreover, the power of a directed energy weapon diminishes
over distance, so such a weapon employed from the air must
have that much more power to begin with to be effective.
A small engine, about the size and shape of a garbage can,
is being developed that will be able to generate four megawatts
of power. Called the Multimegawatt Electrical Power System,
it would be mounted on the wing root of an aircraft such as
the E-3 AWACS.
“We will do a megawatt demonstration in ’07,”
Erno reported, and she hopes a four-megawatt, deployable system
will be developed by 2009.
The device, which will have a motor spinning at 16,000 rpm,
will be useful for “any platform with multimegawatt power
requirements,” such as Joint STARS or AWACS, Erno said.
Air Force Special Operations Command is also showing interest.
AFRL is looking at a directed energy weapon that can cause
“a sensation of pain and heat in the skin ... in the
meters to kilometers range,” Erno reported. This nonlethal
weapon would have many uses in the fight against terrorism.
The generator will also be useful for powering millimeter-wave
radars that will be able to see through foliage and other
obscurants and produce highly detailed imagery.
A destructive laser that would fit on a fighter is the “Holy
Grail” of directed energy research right now, Erno said.
Promising work is taking place in this regard, using superconductivity,
she asserted, but details are classified. |
The Power of Synergy
Yet it was not these isolated advances that made USAF dominant
in air combat. It was, rather, the blending of them that yielded
the huge successes seen in battles in the Balkans and Southwest
Asia. Stealth, coupled with laser designators and GPS-guided munitions,
vastly reduced the number of aircraft needed to successfully strike
heavily defended targets.
Predator’s optical sensors and laser designators made it possible
for attack aircraft to pinpoint and hit targets in complex terrain.
Global Hawk helped US operators “see” through sandstorms
to find the Iraqi Republican Guard, transmitting target GPS coordinates
to aircraft with precision weapons.
“We found out in Iraq the first time, in Kosovo, [and] in
Iraq the second time ... [that] stealth and endurance can give you
immense capability,” Martin said.
The Air Force is looking for capabilities that will similarly redefine
air warfare in the years to come. Martin believes AFMC is pursuing
the right mix.
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| The Airborne Laser carries
a chemical system to power its destructive laser. USAF has not
yet found a destructive laser system that can be carried on
fighters, but researchers have some leads. |
“The ones that are on the horizon ... are directed energy,
information technology, and propulsion,” he said. “Those
are the ones that I think offer the greatest near-term potential
to our military and particularly our air and space forces.”
Directed energy—which encompasses not only lasers of high
and low power but also high-powered microwaves, supermagnetic devices,
and other energies that can be focused—will provide “the
effects of kinetic power as we know it today” from an almost
limitless magazine of ammunition, Martin asserted.
The Airborne Laser’s mission is not to shoot down enemy aircraft,
but “it’s just a matter of time before we have a system
that can also provide some sort of air superiority capability”
with lasers, Martin forecast. Lasers and other such devices will
also provide aircraft facing enemy air-to-air and surface-to-air
missiles “a measure of protection ... that we’ve never
had before.”
In propulsion, a big breakthrough could not only make possible
advanced long-range strike systems—such as hypersonic cruise
missiles or aircraft—but also provide a quick and responsive
“tactical insertion of assets into orbit.” This ability
to lift “relatively inexpensive projectiles into space for
short periods of time—short meaning maybe a couple of months—gives
us an option” to gain persistent intelligence-surveillance-reconnaissance
“anywhere in the world whenever we want it.” Such propulsion
capability doesn’t exist yet.
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The Funding
Picture
The Air Force’s Fiscal Year 2005 budget request includes
$1.4 billion for science and technology efforts. These are
defined by categories. Category 6.1 is basic research into
areas with high potential for a military payoff. Category
6.2, which gets more than half of S&T funding, is aimed
at solving specific military problems or creating specific
capabilities. Category 6.3 is advanced technology development,
which involves building hardware that could actually be used
in the field in an experimental way.
Gen. Gregory S. Martin would like to see a 20 to 25 percent
increase in S&T funding, specifically for “wildcatting”
more concepts in areas 6.2 and 6.3.
The Air Force determines its priorities for spending on science
and technology by comparing guidance from a number of sources.
These include the National Military Strategy, internal defense
planning documents, Joint Staff guidance, and the Air Force’s
own Strategic Plan.
Beyond that, the service engages in exercises that determine
capabilities the service knows it will need in the near- and
long-term future. It then balances these needs with spending
on technologies that can cut operating or ownership costs
or revolutionize military operations.
“Our corporate investment strategy also zeroes in on
evolutionary technologies like the scramjet, which in the
near term can function as a hypersonic cruise missile and
in the midterm is envisioned as an affordable, on-demand access
to space with airplane-like operations,” said Maj. Gen.
(sel.) Perry L. Lamy, head of the Air Force Research Laboratory.
The “cornerstone” of all Air Force S&T investments
is balance, Lamy said.
USAF has 10 major technology areas, of which the largest share
of investment goes to propulsion, basic research, and space
and air vehicles (see chart p. 37). |
Stymied
Martin noted that hypersonic manned flight dates to the 1960s,
when the X-15 research craft took men to the edge of space and back
in a controlled way. However, he said, “we’ve gone nowhere
in hypersonics because of a failure to produce a propellant—and
primarily an air-breathing type of propellant. That’s where
we’re stymied.” The Air Force has not seen a value in
hypersonics unless it worked on a reusable, air-breathing vehicle.
“That’s coming along very slowly,” Martin admitted.
The fuel and the engine have to be developed in tandem. “We’re
not spending enough money on those kinds of things right now to
create that breakthrough,” he said.
There’s another good reason that hypersonics research shouldn’t
be rushed, Martin added. Right now, there’s no value in going
faster until the other parts of the Air Force’s global strike
capability can keep up.
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| Technologists don’t believe
a reusable single-stage-to-orbit vehicle is possible in the
near future. In the interim, USAF hopes to have a two-stage
vehicle for quick access to space by 2013. (Photo illustration
by Erik Simonsen) |
Martin noted a study in which the National Academy of Sciences
“took a look at hypersonics, and they said, frankly, ‘You
don’t have an information/decision process that can respond
fast enough to make hypersonics useful to you.’ ”
As an example, Martin recalled an attack, late in Gulf War II,
on a purported hiding place of Saddam Hussein. It took 35 minutes
from receiving a tip-off regarding Saddam’s whereabouts until
the decision was made to order a B-1B bomber to attack the site.
The B-1B’s ordnance hit the target a scant 12 minutes later.
“Thirty-five minutes to get the data, determine its value,
understand what we had, and make a decision to then execute,”
Martin lamented. “So, again, the hypersonics wouldn’t
have solved this problem. You have to make the decision inside of
two or three minutes and then have a machine that can get there
within two or three minutes in order to ... do that. That’s
what the academy ... was saying.” He added that “we’re
getting there.”
What’s needed is a complementary development called Predictive
Battlespace Awareness, said Martin. In this concept, the US military’s
network of sensors would track vehicles and enemy commanders. Computers
would analyze the movements, patterns, and history of those being
watched and deduce what they will do next, under certain pressures.
“That’s where that technology has to come,” Martin
said. “What I don’t want to do is ... wait until I get
that, then wish I had a kill vehicle. So, I need to [simultaneously]
pursue them both. ... I can’t overemphasize the importance
of our predictive knowledge, ... to be able to know where something’s
going to be.”
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| The Administration’s
2005 defense budget included a total of $1.4 billion for S&T.
Basic research (6.1) accounts for less than 20 percent of those
dollars. Applied research (6.2) and advanced technology development
(6.3) make up the dominant share. |
Speed of Light
Complementing high-velocity analysis, decision-making, and vehicles
would be directed energy weapons, which could then attack at the
speed of light. Right now, state-of-the-art attack systems “will
not be able to respond” at the speed that will be demanded
by such future predictive methods, “so we should pursue that,”
said Martin.
Information technology has greatly advanced USAF’s ability
to spot and track targets and manage large numbers of vehicles,
personnel, and supplies. Yet the trick that is still to be mastered
is “for us to do a much better job of fusing and animating
the information in a way that it is useful at a glance to the decision-maker,”
Martin explained. “Today we’re into data streams, streaming
video, and all kinds of data but not actionable information, in
many cases.”
While some technologies tend to advance at a nearly predictable
rate—computer processing speed, for example, doubles every
two years or so—other areas, such as propulsion, depend on
big breakthroughs that come many years apart.
“This technological explosion has energized a process of developing
the next need,” Martin observed. He went on to say that appetites
for new capabilities are developing “faster than the technology
can develop, and there will be a tension there that will not always
be healthy.”
The Air Force’s acquisition and technology apparatus, he said,
will get hit with “potshots” for not delivering new capabilities
at the desired speed—despite the fact that, on the whole, technology
advances are coming faster than ever before.
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| New propulsion technology is
at the heart of today’s R&D. Martin said not enough
money is going to the effort, though. Above, an AFRL technician
examines a new heat-resistant material for use with new power
systems. (USAF photo) |
Asked if there is sufficient money in the Air Force’s science
and technology (S&T) accounts, Martin replied, “No. There
isn’t.”
He added that the Air Force is “probably at the 75 to 80 percent
level, in terms of what I think we should have in S&T.”
Martin would like to be able to spend more money on ideas that aren’t
guaranteed to pan out, in “application technology and advanced
technology demonstrations” such as those that led to Predator
and Global Hawk.
“We really don’t have the flexibility to experiment with
many rabbit trails,” he observed. “I think we can do more
prototyping, more wildcatting, if you will, in technology areas.
You may only get one out of 10, but now I’m only trying four,
and it’s going to take me two-and-a-half times that to get
the one.”
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Roger, Scramjet: The High (Speed)
Road to Global Strike
The Air Force has two goals for its high-speed propulsion
work: It wants to develop a capability to get anywhere on
the globe within a couple of hours, and it would like this
same technology to offer a route to low Earth orbit.
The Air Force Research Lab is working on scramjet (supersonic
combustion ramjet) propulsion that may be able to do the trick,
but progress is slow, requiring simultaneous advances in aerodynamics,
wind tunnel development, materials, fuels, and other disciplines.
USAF has devoted $134 million of its own funds and is getting
$53 million more from the Defense Advanced Research Projects
Agency to find the answer.
There are almost limitless applications of such a technology,
according to Robert A. Mercier of AFRL’s Propulsion Directorate.
“In the near term, you could see a hypersonic cruise
missile that can travel hundreds of nautical miles in just
a few minutes,” Mercier said. Such a vehicle would be
highly valuable in strikes against time-critical “as
well as deeply buried targets,” he said. A hypersonic
missile would be able to use its velocity to burrow down through
hardened structures or the earth to reach bunkers far underground,
he said. Hypersonic missiles could also carry submunitions
which, released in the target area, could quickly seek out
and destroy targets of interest.
A notional vehicle, 168 inches long and carried by an F-15E
or in the bomb bay of a B-1B or B-2, it would rely on a booster
rocket to get up to about Mach 4, Mercier said. At that point,
the scramjet would kick in and accelerate the vehicle to Mach
6.5 to 7.0.
Although simple in theory, the scramjet has proved elusive
technologically. Leading edges of the vehicle would heat up
to about 3,000 degrees, requiring use of advanced composite
materials. The vehicle’s shape would also have to be
carefully controlled, and, within the skin, the fuel would
also have to act as a cooling agent.
USAF also wants the fuel to be fairly standard issue, so
that no special handling is required. AFRL is looking to use
JP-7, the same fuel that was used by the SR-71 Blackbird.
The Propulsion Directorate is studying ways “to ‘crack’
the fuel module,” Mercier said, to make it burn faster.
Combustion must take place during the millisecond that the
molecule enters the engine and exits the exhaust.
AFRL does not yet have high-fidelity, high-Mach wind tunnels
for testing these devices, so “flight testing is necessary,”
Mercier said. A goal has been set of flight testing five to
eight vehicles in 2009 at Edwards AFB, Calif.
For a manned vehicle, or one that can attain orbit, the challenges
increase. It is not easy to simply “scale up” the
missile-sized vehicle, said Thomas A. Jackson of the Propulsion
Directorate. While the scramjet missile’s inlet and combustion
chamber will probably be boxy and rectangular, a larger one
might have to be round—with a whole different set of
fluid dynamic computations to make.
Moreover, a larger vehicle would have to get to high speed
on its own—and without rockets. A “combined cycle”
craft with a combination of turbojet and scramjet is envisioned,
where the turbojet would accelerate the vehicle to scramjet
speed, then either be retracted or faired over while the scramjet
engine took over propulsion. The reverse would happen on the
return leg. A similar arrangement might be used as a space-accessible
vehicle. However, re-entry poses yet another raft of issues
for heating and thermal management. |
Friends in High Places
He’d also like to see more ideas from the lowest levels of
technology experimentation get a shot at development. Most big ideas
that have gotten funded—like armed Predator or the Airborne
Laser—were the result of a Chief of Staff, having been exposed
by chance to something in which he saw potential, directing a program
into existence.
Martin pointed out that the Airborne Laser program was generated
by former Chief of Staff Gen. Ronald R. Fogleman, who happened to
be “exposed to” adaptive optics technology at Kirtland
AFB, N.M. When Fogleman learned that the biggest problem in laser
weapons technology was atmospheric turbulence, he realized that
adaptive optics offered a solution, and “he knew we had an
answer, and he directed ... a technology effort” that became
the ABL, Martin explained.
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| Small unmanned aircraft, which
can hold positions for very long periods, have a big future.
This staring, persistent presence over the battlefield has been
“very important” and will become more so, Martin said
(USAF photo by SSgt. Suzanne M. Jenkins). |
“Bottom-up” programs atrophied in the last decade, when
the Air Force’s assorted research labs worked closely with
AFMC’s product centers, Martin said. The creation of the single
overarching Air Force Research Lab was “the right thing to
do, because no longer does one technology solve the problem. You
need a cross-section of technologies applied towards a capability,”
he explained.
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When It Has To Be There Overnight
Technologists agree that a reusable single-stage-to-orbit
craft is probably not possible in the near future, so the
Air Force is looking at a two-stage system that would rely
on a hybrid expendable or reusable vehicle for quick access
to space, according to Lt. Col. James M. Ceney of the Operationally
Responsive Space Technology Office.
USAF wants to be able to loft a small Space Operations Vehicle,
with only a few hours’ notice, that could remain in orbit
for up to several months. The payload might be a reconnaissance
or communications satellite, either to replace a lost asset
or supplement the existing constellation in a crisis.
“If we can pull the funding together, we hope to fly
a demonstrator as early as 2008,” Ceney said. The demonstrator
would be a “little vehicle,” but the objective would
be to launch a small fighter-sized craft. If the craft is
too small, it won’t be able to accomplish missions that
are “relevant,” Ceney said. The vehicles being looked
at commonly resemble “a cylinder with delta wings,”
he reported.
The demonstrator will “take off vertically, go to Mach
4, and then return to base,” but have to fly again in
less than 24 hours, Ceney explained.
USAF wants to decide on a system before 2011 and achieve
a basic capability by 2013. Ceney said the vehicle will be
“all new” and not a rehash of the abandoned X-33
project. It will also not have an aerospike engine as the
X-33 had.
The project hopes to achieve “medium lift” capability,
meaning that it could loft a payload of 10,000 to 15,000 pounds
to low Earth orbit. The Air Force expects the system to be
unmanned. |
Beyond the near term, Martin sees tremendous potential in bio-
and nanotechnologies.
Biotech will permit the sensing of things that could never be detected
before, Martin noted. Included among these are biological agents,
chemical signatures, and contaminants.
Nanotechnology—the art of micro-engineering materials and
devices—will “allow you to ... operate pieces of equipment
so efficiently that you can reduce the size, weight, and redundancy
in a way that you will be able to do huge work with small things,”
Martin said. Visionaries have suggested swarms of tiny robots the
size of bees searching a landscape for enemies or mines, but a more
near-term application will be very small actuators that can cut
weight on an aircraft, or airfoils that can adapt their shape at
the touch of a button.
Martin believes robots and automation “will become more and
more prevalent in our battle force,” but he doesn’t think
they will replace people or reduce the need for manpower.
Predator, he noted, was an idea which, even though it might be
seen as replacing a manned reconnaissance aircraft, was actually
an add-on, new capability that created hundreds of new billets to
fly, maintain, arm, and manage it.
When it comes to replacing humans with uninhabited vehicles and
other machines, the real question is going to be “where will
the man in the loop be, and how many systems will [he] operate,”
Martin predicted. “That will be a slower-developing capability,”
he said.
Such systems will also not be cheap. Although unmanned aerial vehicles
are often viewed as inexpensive and disposable systems, they have
turned out not to be.
“Global Hawk is very expensive,” Martin pointed out.
“So when something goes wrong, we don’t just have a razor
blade you can throw away here. We have a very expensive system that
needs to be recovered.”
Global Hawks have been lost precisely because “we didn’t
really have man in the loop.”
Martin said he is a fan of UAVs, but he wants to use them first
for missions “that we can’t do with man. ... So therefore,
they’re not really replacing man.”
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Down in the Weeds With Nanotechnology
Tiny robots that swarm, adapt, and create virtual sensors—such
as those described in Michael Crichton’s recent best-selling
thriller, Prey—are “still science fiction,”
according to Richard A. Vaia, head of the AFRL Materials and
Manufacturing Directorate’s nanotechnology efforts.
However, the new science—which allows atoms to be manipulated
to create new physical properties of materials—could
offer extraordinary benefits in reducing the size and weight
of aircraft and missiles.
“Nano will impact everything in the Air Force,”
Vaia asserted.
Among the applications now in the pipeline are “superstrong
metals, inorganic coatings for lubrication of gimbals for
spacecraft,” atomically structured coatings for adaptive
optics, and many more, Vaia said. Inorganic lubrication is
a big advance for spacecraft because it “won’t seize
in the vacuum of space.”
Very small, densely packed precise super-lattices, similar
to those offered in commercial digital cameras, will make
it possible to have extremely sensitive infrared sensors in
a small, lightweight package.
Nano-engineered fuel systems will sharply reduce the amount
of propellant that is wasted in solid-fuel rockets and missiles,
making it possible to have smaller vehicles or make existing
ones go farther, Vaia said.
Flexible materials that look like rubber or plastic can be
made electrically conductive. They can also be engineered
so that they reassume a certain shape when current passes
through them. That means nonmechanical actuators, or aircraft
wings that change their shape depending on their mode of flight.
Nanotechnology will vastly improve electrical storage, permitting
much smaller batteries and solar cells. The same principle
will allow new “data storage ... with higher density,”
meaning more data can be crammed into smaller spaces.
In the near term, Vaia said, expect “electrically conductive
adhesives” that will vastly reduce the amount of weight
that must be used for electromagnetic shielding of wires and
devices. |
Copyright Air Force Association. All rights reserved.
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