Does the United States Air
Force or one of America's intelligence agencies have a secret hypersonic
aircraft capable of a Mach 6 performance? Continually growing evidence suggests
that the answer to this question is yes. Perhaps the most well-known event
which provides evidence of such a craft's existence is the sighting of a triangular
plane over the North Sea in August 1989 by oil-exploration engineer Chris
Gibson. As well as the famous "skyquakes" heard over Los Angeles since the
early 1990s, found to be heading for the secret
installation in the Nevada desert, numerous other facts provide an understanding
of how the aircraft's technology works. Rumored to exist but routinely denied
by U.S. officials, the name of this aircraft is Aurora. The outside world
uses the name Aurora because a censor's slip let it appear below the
and U-2 in the 1985 Pentagon budget request. Even if this was the actual
name of the project, it would have by now been changed after being compromised
in such a manner. The plane's real name has been kept a secret along with
its existence. This is not unfamiliar though, the
F-117a stealth fighter
was kept a secret for over ten years after its first pre-production test
flight. The project is what is technically known as a Special Access Program
(SAP). More often, such projects are referred to as "black programs". So
what was the first sign of the existence of such an aircraft? On 6 March
1990, one of the United States Air Force's Lockheed
spyplanes shattered the official air speed record from Los Angeles to
Washington's Dulles Airport. There, a brief ceremony marked the end of the
's operational career. Officially, the SR-71
was being retired to save the $200-$300 million a year it cost to operate
the fleet. Some reporters were told the plane had been made redundant by
sophisticated spy satellites. But there was one problem, the USAF made no
opposition towards the plane's retirement, and congressional attempts to
revive the program were discouraged. Never in the history of the USAF had
a program been closed without opposition. Aurora is the missing factor to
the silent closure of the SR-71
Testing such a new radical aircraft brings immense
costs and inconvenience, not just in the design and development of a prototype
aircraft, but also in providing a secret testing place for aircraft that
are obviously different from those the public are aware of.
Groom Dry Lake
, in the Nevada desert, is home to one of America's elite secret proving
grounds. Here is Aurora's most likely test location. Comparing today's
with images of the base in the 1970s, it is apparent that many of the
larger buildings and hangars were added during the following decade. Also,
the Groom Lake
test facility has a lake-bed runway that is six miles long, twice as long
as the longest normal runways in the United States. The reason for such
a long runway is simple: the length of a runway is determined either by
the distance an aircraft requires to accelerate to flying speed, or the
distance that the aircraft needs to decelerate after landing. That distance
is proportional to the speed at which lift-off takes place. Usually, very
long runways are designed for aircraft with very high minimum flying speeds,
and, as is the case at Edwards AFB, these are aircraft that are optimized
for very high maximum speeds. Almost 19,000 feet of the runway at
is paved for normal operations.
Lockheed's Skunk Works, now the Lockheed Advanced
Development Company, is the most likely prime contractor for the Aurora aircraft.
Throughout the 1980s, financial analysts concluded that Lockheed had been
engaged in several large classified projects. However, they weren't able
to identify enough of them to account for the company's income.
Technically, the Skunk Works has a unique record
of managing large, high-risk programs under an incredible unparalleled secrecy.
Even with high-risk projects the company has undertaken, Lockheed has a
record of providing what it promises to deliver.
By 1945, only a small amount of jets had the capability
of reaching speeds of 500mph. In 1960, aircraft that could exceed 1,500mph
were going into squadron service. Aircraft capable of 2,000mph were under
development and supposed to enter service by 1965. This was a four-fold increase
in speed in two decades.
From this, the next logical step was to achieve
hypersonic speed. The definition of hypersonic isn't as clearly defined as
supersonic, but aerodynamicists consider that the hypersonic realm starts
when the air in front of the vehicle's leading edges "stagnates": a band
of air is trapped, unable to flow around the vehicle, and reaches extremely
high pressures and temperatures. The edge of the hypersonic regime lies at
a speed of roughly one mile per second - 3,600mph or Mach 5.4.
What is regarded by many as the most successful
experimental aircraft program in USAF history, the X-15 rocketplane was created
in response to a requirement issued by NASA (then NACA) for an air-launched
manned research vehicle with a maximum speed of more than Mach 6 and a maximum
altitude of more than fifty miles.
The X-15 program, which involved three test aircraft,
went on to exceed all goals set and provided valuable data which has been
used on many high speed/altitude aircraft of today, including NASA spacecraft,
and most likely, the Aurora aircraft. In the early 1960s, Lockheed and the
USAF Flight Dynamics Laboratory began a hypersonic research program which
would provide data on travel at hypersonic speed as well as more efficient
shapes for hypersonic vehicles. From this program came the FDL-5 research
vehicle, which beared an amazing resemblance to the North Sea Aurora sighting
of Chris Gibson. Building on both the FDL-5 Project and Aurora, the aircraft
which may have been seen over the North Sea could have been
Northrop's A-17 stealth attack plane
Possible forms of hypersonic propulsion
that Aurora could be using include:
Pulse Detonation Wave Engines
There are three reasons why the North Sea
sketch drawn by Chris Gibson is the most persuasive rendition of the Aurora
vehicle. Firstly, the observer's qualifications, with which he couldn't identify
the aircraft; which would have been instantaneous if the aircraft was known
to the "white world". Second is the fact that the North Sea aircraft corresponds
almost perfectly in shape and size to hypersonic aircraft studies carried
out by McDonnell Douglas and the USAF during the 1970s and 1980s. The third
factor is that the North Sea aircraft looks unlike anything else. No aircraft
other than a high-supersonic vehicle, or a test aircraft for such a vehicle,
has ever been built or studied with a similiar planform.
At hypersonic speeds, traditional aerodynamic
design gives way to aero-thermodynamic design. In order for a hypersonic
vehicle to remain structurally intact at such high speeds and stresses, the
vehicle must produce minimum drag and be free of design features that give
rise to concentrations of heat. The aircraft design must be able to spread
the heat over the surface of the structure. Thermal management is critical
to high-speed aircraft, especially hypersonic vehicles. Skin friction releases
heat energy into the aircraft and must be pumped out again if the vehicle
is to have any endurance. The only way to do this is to heat the fuel before
it enters the engine, and dump the heat through the exhaust. On a hypersonic
vehicle, thermal management is very critical, the cooling capacity of the
fuel must be used carefully and efficiently or else the range and endurance
of the aircraft will be limited by heating rather than the actual fuel tank
So how will an aircraft reach such speeds?
Conventional turbojet engines won't be able to handle the incoming airstreams
at such speeds, they can barely handle transonic speeds. In the case of
hypersonic propulsion, an aero-thermodynamic duct, or ramjet, is the only
engine proven to work efficiently at such speeds. Even ramjets have drawbacks
though, such as drag created in the process of slowing down and compressing
a Mach 6 airstream. To make a ramjet engine efficient is to spread the air
over the entire length of the body. In a hypersonic ramjet aircraft, the
entire underside of the forward body acts as a ramp that compresses the air,
and the entire underside of the tail is an exhaust nozzle. So much air underneath
the aircraft serves another purpose, it keeps the plane up. The ramjets need
a large inlet area to provide the high thrust needed for Mach 6 cruise. As
a result, the engines occupy a large area beneath vehicle and the need to
accomodate a large quantity of fuel means that an all-body shape is most feasible.
Structurally, the all-body shape is highly
efficient. As well as being extremely aerodynamic, the average cross-sectional
area being very large provides a great deal of space for load, equipment
and fuel. This being inside a structure that is light and compact having
a relatively small surface area to generate frictional drag. The spyplane's
airframe may incorporate stealth technology, but it doesn't really require
it should its mission simply involve high altitude reconnaissance. Hypersonic
aircraft are much harder to shoot down than a ballistic missile. Although
a hypersonic plane isn't very maneuverable, its velocity is such that even
a small turn puts it miles away from a SAM's projected interception point.
Choosing The Right Fuel
Choosing the right type of fuel is crucial to
the success of Aurora. Because various sections of the craft will reach cruising-speed
temperatures ranging from 1,000 degrees fahrenheit to more than 1,400 degrees
fahrenheit, its fuel must both provide energy for the engines and act as
a structural coolant extracting destructive heat from the plane's surface.
At hypersonic speeds, even exotic kerosene such
as the special high-flashpoint JP-7 fuel used by the
can't absorb enough heat. The plausible solution is cryogenic fuel.
The best possibilities are methane and hydrogen.
Liquid hydrogen provides more than three times as much energy and absorbs
six times more heat per pound than any other fuel. The downfall is its low
density, which means larger fuel tanks, a larger airframe and more drag.
While liquid hydrogen is the fuel of choice for spacelaunch vehicles that
accelerate quickly out of the atmosphere, studies have shown that liquid
methane is better for an aircraft cruising at Mach 5 to Mach 7. Methane is
widely available, provides more energy than jet fuels, and can absorb five
times as much heat as kerosene. Compared with liquid hydrogen, it is three
times denser and easier to handle.
Current Knowledge of Aurora
On 16 November 1998, a camcorder video was taken
of a mysterious "fireball" in the sky. While this was very interesting, what
was even more amazing was the aircraft which was seen shortly after flying
at very high speed producing the mysterious "donuts-on-a-rope" contrails.
Does this video, which is currently undergoing intense study at JPL, show
the mysterious Aurora spyplane?