[ music ]
On November 28th, 1938,
legendary aviator Charles Lindbergh sat
down to write a letter to his colleague Joseph Ames.
Lindbergh had been visiting Germany regularly
for several years during a period
of aeronautical achievements such as the Hindenburg airship,
the first supersonic wind tunnel, and the construction
of the first turbojet engine.
He had become increasingly concerned
that German military aircraft were flying higher and faster
than their U.S. military counterparts.
One reason was the coordination
of their national research efforts.
They had very large government research centers which focused
on engine development.
And these large research centers had very good relationships
with private industry.
Lindbergh wrote, "It is more necessary than ever before
to give full scope to research if we are
to regain the leadership we have lost in some of the fields
of military aviation."
Written just weeks after the terrifying Kristallnacht attacks
in Germany shook the U.S. from its complacency,
Lindbergh's letters became a key factor in the decision
to create a state-of-the-art aircraft engine research
laboratory in Cleveland, Ohio.
[ Music ]
The National Advisory Committee for Aeronautics,
or N-A-C-A was founded by Congress in 1915
to help the U.S. compete with Europe in the area
of aeronautical technology during World War I.
The NACA was a precursor the National Aeronautics
and Space Administration, or NASA, of today.
As the threat of World War II loomed,
NACA expanded its research
and opened two new laboratories -one dedicated to the study
of engines was located in Cleveland, Ohio.
This "Aircraft Engine Research Laboratory," or AERL,
included the nation's first wind tunnel
for studying actual aircraft engines
in the same conditions they would experience during flight.
The Altitude Wind Tunnel, or AWT allowed researchers
to systematically study aircraft engine behavior
and perfect new innovations in aeronautics.
Designed by some of the best and brightest minds of the day,
the AWT proved itself to be a crucial
and versatile testing facility-from supporting the
development of the jet engine during the 1940s and 50s,
to its rebirth in the 1960s for Project Mercury
and Centaur rocket testing.
The AWT was a huge project.
This was, as you can see it's a massive massive structure
and there was no technology that would tell you how
to build something like this.
It was all new.
The Altitude Wind Tunnel was likely the most advanced wind
tunnel of its time.
Designed by engineers at NACA's Langley and Ames laboratories,
the AWT included a number of ingenious features needed
to test full-scale aircraft engines in the airspeed,
altitude, and air quality experienced during flight.
This facility had to get temperatures that were very,
very cold and the air had to be almost a vacuum.
And this was very difficult to do in a structure this size.
And the amazing thing was that it all worked perfectly.
The wind stream of the AWT was created
by a massive 31-foot propeller, resulting in airspeeds
that could reach 500 mph!
As the wind stream raced down the tunnel,
turning vanes directed it around the corners
and straightened the flow.
A powerful refrigeration system reduced the temperature
to minus 47 degrees.
Large exhausters in the Exhauster Building removed air
from inside the tunnel
to simulate the thin atmosphere found at high altitudes.
Just prior to reaching the test section, the diameter
of the tunnel decreased in order to further increase the speed
of the arctic wind stream as it rushed
into the 20-foot-diameter test section.
The roaring engine in the test section was operated remotely
from the soundproof control room,
as myriad instrumentation recorded tunnel conditions
and engine performance.
Engine contaminants were exhausted from the tunnel
through a large air scoop located just beyond the
test section.
Fresh air was introduced into the wind stream prior
to the test section to make up for this exhausted air.
One of the most daunting engineering tasks in the design
of the AWT was the creation of a system
to reduce the air temperature to frigid temperatures encountered
in altitude conditions.
This powerful system had to cool millions of cubic feet
of airflow every minute-an unprecedented requirement
that caught the attention of the one man considered
to be a world expert on the cooling of air-Willis Carrier.
Willis Carrier had pioneered the field of air conditioning,
and felt his company's heat transfer experts should be
designing the AWT system.
He informed the NACA that,
"the Langley boys conducting the tests did not know what it was
all about, and that too much money, and of more importance,
too much time had been wasted already."
Carrier and his engineers went
on to devise the AWT cooling system -
the largest of its kind in the world.
In fact, it was claimed that if the massive cooling system were
used for other purposes,
it could generate 10,000 tons of ice per day.
Willis Carrier would one day refer to the AWT
as his greatest achievement.
Construction of the AWT had begun
as the U.S. entered World War II.
There was considerable pressure
to complete the construction quickly,
in order to aid the war effort.
The new B29 Superfortress, in particular,
was suffering problems with its engines as it attempted
to reach a 30,000- foot cruising altitude.
The AWT had been designed to resolve just such an issue.
On May 17th of 1943, the Memphis Belle became the first heavy
bomber in World War II
to successfully complete 25 bombing missions.
Within two months, the Memphis Belle and her crew were back
in the U.S. and visiting the AERL
as part of a publicity tour.
In the hangar behind the bomber the large fan
for the AWT was being assembled.
By 1944, construction was completed
and the AWT opened its doors for business.
Standing inside a wind tunnel,
it is easy to lose one's sense of perspective.
Inside, all lines converge toward a single,
amorphous vanishing point - a virtual "light
at the end of the tunnel."
In order to gain some perspective
on the true dimensions of the tunnel, it is helpful
to bring a person into view.
In much the same way, the research conducted at the AWT,
and the scope of its changing mission can be best put
into perspective by bringing a different individual
into frame -Dr.
Abe Silverstein.
Dr. Abe Silverstein is best known as one of NASA's
"founding fathers," and is credited
with having named the Mercury and Apollo programs.
He began his career in 1929, as an NACA researcher,
at Langley's massive, Full Scale Wind Tunnel.
In 1943, he was transferred to Cleveland
to manage the newly constructed Altitude Wind Tunnel.
He immediately set to work,
assembling a 90-person team to run the tunnel.
Many had been involved in its design and construction.
Behind the scenes, Silverstein was involved
in something far more secretive...
The nation's first turbojet engine.
The jet engine was developed independently in both Germany
and Great Britain during the 1930s.
American military leaders had witnessed the first British test
flight of the engine in 1941.
Plans for the engine were soon secretly transferred to the U.S.
where General Electric, or GE, assembled it
to create the I-A engine,
which was almost immediately upgraded and renamed the I-16.
The I-16 was incorporated into a Bell YP-59A Airacomet airframe.
In 1943, GE summoned Abe Silverstein
to its West Lynn facility to discuss testing the I-16
in altitude conditions.
When later asked why he was selected to participate
in the secret project, Silverstein replied,
"We had the only altitude tunnel.
That's the reason l went."
Soon afterward one of the jets was flown to Cleveland
for testing in the AWT.
Modifications, based on the AWT studies,
allowed better distribution of airflow
and reduced drag-improving the aircraft's performance
by 25 percent.
However, the Airacomet would not play a role in World War II.
The tests would portend an entire new role
for the AWT-the development of the turbojet.
[ Music ]
In May 1944 an engine from the Boeing B-29 Superfortress was
finally installed in the AWT.
Researchers determined that its cooling problems stemmed
from inconsistent fuel mixtures and poor airflow.
By devising a fuel injection system
and redirecting the air flow through the engine's cylinders,
they were able to improve the fuel efficiency by 18 percent,
thus broadening the, B-29's flight range
and increasing its armament capabilities.
The results were too late, however.
The B-29's original strategy of high-altitude precision bombing
of Japan had been changed to low-altitude firebombing,
and the NACA's improvements were not implemented
until after the war.
The Lockheed YP-80A Shooting Star was the first jet aircraft
to be completely manufactured in the U.S.,
and the first U.S. aircraft to ever fly faster
than 500 miles per hour.
Studies on the engine at the AWT resulted in the restarting
of its GE I-40 engine above 20,000 feet for the first time,
and an almost instantaneous 50-percent increase in thrust
through use of a variable-area nozzle.
The Shooting Star would later go on to a successful reincarnation
as the Lockheed F-80 during the Korean War.
In the end, the AWT had little effect
on the outcome of the war.
Its most applicable contribution, the baffling
of the B-29 engines, was not implemented until later.
Although U.S. development
of the turbojet would not be fast enough
to make any significant impact on the outcome of the war,
it did have long-term effects.
The AWT demonstrated remarkable flexibility
and became a significant contributor
in developing the nation's first jet engines,
both centrifugal and axial-flow.
The AWT had not only survived the turbojet revolution,
it had embraced it.
During its first 18 months of service, the tunnel was modified
to test jet engines, the staff showed
that it could handle the new facility, a methodology
of analysis was established that would be applied repeatedly
over the next decade, and the emerging AERL leadership showed
that it could change course with almost no warning.
The end of World War II brought about a reorganization
of the entire laboratory.
Turbojet research and the new realm
of high-speed flight became the top priorities.
Abe Silverstein was promoted to Chief of the Wind Tunnels
and Flight Division and in 1949 became Director of Research
for the entire laboratory.
One of the most significant problems
with the early turbojets was combustion at high altitudes.
The AWT was the nation's only facility in which the combustion
and performance characteristics of a turbojet could be studied
under altitude conditions.
Nearly every U.S. jet engine model
in the 1940s was tested in the AWT.
The engine companies would send their engines here,
and they would be just put through their paces.
And a great deal of marvelous data was then able
to be released to the engine companies.
Components such as the variable-area nozzle
and afterburner were run successfully
for the first time in the AWT.
The afterburner was actually developed at NASA Lewis,
and there's a story about Abe Silverstein, who was Director
of Research, who peaked in the window
and saw this plume fire coming out of that afterburner,
and he was thrilled because it was the first time it had
been tested.
As the 1940s drew to a close,
the AWT completed its first sprint.
The tunnel had been in almost constant operation
for six years.
It had played an important role in the steady development
of the jet engine and was used to study ramjets and turboprops.
The study and improvement of the axial-flow engine from 1945
to 1949 was the AWT's most enduring contribution
to the aerospace field.
The axial-flow compressor was really the great contribution
that this center made to the development of jet engines.
The United States was really the pioneer in the development
of the axial compressor.
Although they had been used in Europe they weren't perfected
until Lewis Research Center got their hands on them.
The improvements developed
in the 1940s would manifest themselves
with drastic increases in engine performance
and thrust in the early 1950s.
In 1952 the AWT underwent an overhaul
to increase its testing abilities.
A new fan, exhausters, exhaust cooler,
and water pump system were added.
Afterwards a series of larger engines were tested
in the tunnel.
Pratt & Whitney's J57 engine,
was probably the most successful jet engine of this period.
The AWT conducted both general engine studies
and a yearlong noise suppression investigation on the J57.
By the late 1950s, however,
use of the subsonic AWT began declining,
and NACA aircraft engine research began plateauing.
Some engineers were wondering, "Where do we go from here?"
The answer came on October 4, 1957, with the launch of Sputnik
and the laboratory's integration
with the new NASA space agency one year later.
Silverstein had been summoned to Washington, D.C. to help create
and lead the new agency.
The NACA Aircraft Engine Research facility was renamed
NASA Lewis Research Center.
The AWT would play a significant role in NASA's first effort,
Project Mercury, only not as a wind tunnel.
The agency began to recognize
that at some point all these aeronautical capabilities had
application for advancing technologies needed
for space travel, space exploration.
AWT was one of the prime examples.
The refrigeration coils and turning vanes were removed
from the western leg of the tunnel
so that the Big Joe attitude control
and retrorocket system could be tested
at simulated altitudes up to 80,000 feet.
Big Joe was a successful single attempt early in Project Mercury
to use a full-scale Atlas booster and test the reentry
of a boilerplate Mercury capsule
without actually placing it in orbit.
Lewis[svh1] designed the attitude control system
and assembled the components.
Its guidance system was tested in the AWT.
Mercury capsule testing in the AWT continued afterwards
with the separation system for the Atlas and Redstone boosters,
retrorockets calibration, and escape tower rockets.
Perhaps the best-known AWT studies, however,
were conducted in "the gimbal rig."
A gimballing platform had been set up in the AWT
for the Big Joe tests.
Afterwards a pilot's chair, mock control panel,
and nitrogen jet control system were added to the rig.
The Mercury astronauts would use this Multi Axis Spin Test
Inertial Facility or MASTIF
to practice bringing a tumbling spacecraft under control.
A crude dressing room known as the "Astro-Penthouse,"
was temporarily constructed in the AWT with a cot
for astronauts to recuperate on after their rides.
In early 1960 the seven astronauts,
a female astronaut trainee, and several pilots traveled to Lewis
to train on the MASTIF.
Alan Sheppard would be first.
On the initial runs Sheppard did well bringing the machine
under control on one and two axes.
Once all three axes were in motion, however,
Sheppard became ill and had to activate the "chicken switch"
that signaled to the engineers to shut down the machine.
Over the next few days, however, Sheppard continued to climb
into the rig until he developed a method
to bring the machine to a standstill.
John Glenn, Gus Grissom, and the others followed suit.
When the AWT had come online just 15 years before,
no one could have foreseen that it would be used
as an altitude tank for manned space missions,
but once again it and its staff adapted quickly
and contributed to a new role.
Out of the test cells, these wonderful mechanics
and technicians came and switched their attention
from airplane problems to space problems.
We found that transition was almost seamless.
The Big Joe capsule verified
that the autopilot could keep the heatshield
in position during reentry.
The Mercury escape system was never deployed during an actual
launch, but the tumbling capsule scenario did manifest itself
on Neil Armstrong and Dave Scott's Gemini VIII mission.
Following the decision to attempt to go to the moon,
NASA began rapidly expanding its staff and test facilities.
The space effort is extremely interesting and it is an area
in which there will be considerable growth
for the future.
I think the young men in this country
who have been properly trained in the sciences
and technology are in many cases eager to get into the program
and this will afford them the opportunity.
The beauty of government facilities is
that they can be adapted to a variety of uses.
And it's not really the facilities, but the people
who are so creative and able to do this.
And they were able to find new uses for old structures.
One capability considered necessary
by Lewis[svh2] was a large space simulation chamber.
Initial spaceflights revealed that the behavior of engines,
operating systems, and flight hardware were affected
by the environmental conditions encountered in space.
It was decided to construct two test chambers
within the AWT's tunnel shell-one capable
of simulating the altitudes of outer space,
the other of earth's upper atmosphere.
Bulkheads were placed within the tunnel
to seal off the new chambers, the exterior shell
of the east end was rewelded,
and a Vacuum Pump House was built underneath.
After over a year of construction,
the facility was officially renamed the Space Power
Chambers, or SPC, on September 12, 1962.
Its mission, however,
would change dramatically just weeks later.
Centaur was a powerful second-stage rocket designed
by General Dynamics to run on liquid hydrogen and oxygen.
It had a sophisticated design that allowed it
to carry larger payloads and restart its engines in space.
NASA was relying on the new rocket to send a series
of the Surveyor spacecraft to the Moon to photograph
and sample the lunar surface as a precursor
to the Apollo landings.
We didn't know a lot about the moon,
so programs like Lunar Orbiter were designed to find out things
that were important to the design of the Apollo lander,
in fact, the entire Apollo system.
After its initial launch exploded 49 seconds
into the mission, the program was transferred to Lewis[svh3].
Silverstein returned to Cleveland as Center Director
in 1961 and personally oversaw the Centaur work.
After a year of modifications and testing
at Lewis' other facilities the second Centaur launch
was successful.
It was a very exciting time.
We were working on a high priority program.
It had the highest national priority.
It was a precursor to Apollo.
Apollo was not going to happen
without our perfecting the Centaur
so the Centaur could complete the Surveyor Program.
The first study in SPC's high altitude chamber [svh4]analyzed
the retrorockets, which separated the Centaur
from the Atlas booster.
A model that recreated the mass properties
of a full-size Atlas/Centaur was hung horizontally
on a trolley system.
These tests would result in a new jettison method
that significantly reduced the separation time
and thus minimized the danger of collision
between the two stages during separation.
A number of modifications were made to the SPC vacuum tank
to accommodate a full-scale Centaur.
The most prominent of which was the addition
of a cylindrical extension with a detachable dome
so that the rocket could be positioned vertically.
A complex setup was installed inside the chamber
to replicate other aspects of outer space.
A liquid nitrogen-filled cold wall enveloped the Centaur
to simulate the cryogenic temperatures of space.
Solar radiation was replicated using six banks of quartz lamps.
Exhausters below the chamber created pressure levels found
at an altitude of 100 miles.
Electronic malfunctions were the most likely cause
of failures in space.
The Silverstein Doctrine said that anything
that can be tested meaningfully
on the ground before flight will be.
That is to say conditions can be simulated accurately enough
that you can do a meaningful test.
We had to construct an entire control room
that looked very much if not almost identical
with the control room to be found at the launch complex
at Cape Kennedy had to be duplicated here.
That's how you run the systems on the Centaur.
In October 1963 a Centaur rocket was flown
to Cleveland for the tests.
And that Centaur was brought from there to Cleveland.
I was here the day it arrived.
I'll never forget it.
And then it was set into the chamber
in a vertical state, on the stand.
Long soaks inside SPC's vacuum tank would help the Lewis team
determine the effects of the space environment
on Centaur's electronics.
For several months General Dynamics personnel worked
with Lewis researchers as they studied
and began reassembling the rocket in the shop area.
Our engineers, our mechanics, our technicians,
who had never before been exposed to a machine
like the Centaur, had to become educated
about what it is, how to handle it.
Especially this fragile thin-walled structure,
that you had to be very careful handling
because it could not sustain its own weight.
The effect of heat, both on the electronics and emanating
from the electronics, was one of the primary concerns going
into the Centaur tests.
The liquid-hydrogen propellant had an extremely low boiling
point so any additional heat could cause problems.
We had to have step by step procedures
that were carefully controlled, changes were controlled.
We were all on headsets.
We'd sit at our consoles and operate our systems.
I had the range safety control, C-band telemetry systems
under my responsibility.
We ran through our procedures under the control
of the test conductor.
And it would take the better part of a day to get
through a number of runs.
The SPC tests, which replicated the entire mission except the
firing of the engines,
determined that the electronics did not transfer heat
to the spacecraft or propellant tanks.
So that testing was done here and it was a major step forward
in increasing the reliability of the Atlas Centaur.
The June 30th, 1964, launch of Atlas-Centaur-3 was successful,
but the rocket's guidance computer had been interrupted
briefly during the ejection of the nose fairing.
This mishap could result in a future launch failure.
Nose fairings provided an aerodynamic shield
for the payload, guidance system and electronics package
as the rocket travels through the Earth's atmosphere.
Upon entering space, the two pieces are ejected away
from the space vehicle.
The trick is to get those shrouds,
after then appropriate period of time in flight,
those shrouds separated and safely
so they don't damage the rocket,
they don't damage the spacecraft,
but they do come off.
Within a month of the AC-3 incident,
the jettison system was modified
and shroud requalified in the SPC.
The next launch was the first Centaur mission
to have a completely error-free shroud jettison.
The following launch attempt, Atlas-Centaur-5,
never escaped the pad, however.
An ensuing redesign required a retesting of the shroud in SPC.
We did many, many tests of Centaur shrouds on both ends,
beginning with the Surveyor, the first payload carried
by Centaur, and later, to larger shrouds
that involved Orbiting Astronomical Observatories was
done at the other end of the chamber.
Atlas-Centaur-6, launched from Cape Canaveral on August 11,
1965, successfully placed a Surveyor model
into an elliptical Earth orbit.
The mission restored the nation's confidence
in the Centaur's capabilities.
Finally, on May 30, 1966,
the Atlas-Centaur-10 vehicle lifted off
from Cape Canaveral carrying the Surveyor 1 spacecraft.
The Centaur stage performed perfectly,
and Surveyor was on its way.
Three days later the Surveyor began sending back images
from the surface of the moon.
The problematic Centaur had been turned
into a tremendous success thanks in part
to the testing at the SPC.
Four years of intense work at the Center had paid off.
A series of satellites carrying large telescopes
in the late 1960s and early 1970s were designed
to view distant stars and galaxies.
The high altitude SPC chamber was used
to test the shroud separation systems
for most of these missions.
The second of these, launched in 1968,
was the largest payload ever carried by a Centaur.
After only a month the satellite obtained
over twenty times more ultraviolet data from stars
than all of the sounding rocket studies
of the previous fifteen years combined.
The next mission, however, failed when one
of the bolts securing the shroud did not release.
The SPC was used for the failure investigation and testing
of the new single-motion design.
SPC continued these large shroud jettison tests
for additional missions until 1975
[ Music ]
The SPC had proven its value during the extensive Centaur
testing of the 1960s.
However, newer, more powerful facilities began
to supersede its abilities.
By the mid-1970s, the Space Power Chamber was shut down.
Useable equipment was removed, doors were shut,
the electrical connections severed.
...and the light at the end of the tunnel, went dark.
Over the coming years, the shop area was repurposed for work
on electric vehicles,
and eventually became a successful antenna
testing facility.
In 1985, an extensive effort was made to study a proposal
to restore the AWT wind tunnel research
for Vertical and/or Short Take-off and Landing, or V/STOL,
high-speed turboprop and rotocraft testing.
When Congress canceled the proposed restoration,
the tunnel slipped into a deep hibernation.
Though the steel behemoth would continue to stand,
the rust was slowly beginning to show.
The stories of the Altitude Wind Tunnel
and Space Power Chambers were fading, along with the men
and women who had once brought the facilities
to thundering life.
The once thriving facility would remain inky black
and dead-quiet for 25 years.
In December of 2008, there was a clamoring
on the outside tunnel wall.
After a few minutes, molten steel began
to drip to the tunnel floor.
The tunnel had been built to resist the forces
of high-speed winds and a crushing vacuum environment.
However, it was no match for the blazing hot knife
of a cutting torch.
The AWT and SPC were coming down.
In 2004 NASA Headquarters had offered its centers funds
to demolish unused structures.
The NASA center in Cleveland -
which had been renamed the Glenn Research Center -
decided it was time to remove the AWT and SPC.
[ music ]
NASA Glenn spent three years photographing, researching,
and documenting the history of the AWT before its demolition.
The AWT/SPC facility was one
of the most successful test facilities
for both the NACA and NASA.
And yet, the true strength
of the AWT/SPC facility cannot be measured in terms
of steel and wind speed.
For, the building itself would be of minimal benefit,
were it not for the excellence of its staff
and farsighted leadership, as exemplified
by Dr. Abe Silverstein.
[ music ]
The tunnel is now gone.
The echoes of its highly-skilled staff
and the advancements they made, live on.