2004-2-17
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ANNCR:
Explorations -- a program in Special English by the Voice of
America.
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Today, Doug Johnson and Frank
Oliver tell about the first airplane that flew out of the Earth's
atmosphere. It was designed to test equipment and conditions for
future space flights. The plane was called the X-15.
VOICE ONE:
The pilot of the huge B-52 bomber plane pushes a button. From
under the plane's right wing, the black sharp-nosed X-Fifteen drops
free. It is eleven-and-one-half kilometers above the Earth.
Pilot Scott Crossfield is in the X-15's only seat. When he is
clear of the B-52, he starts the X-15's rocket engine. And so begins
the first powered flight of the experimental plane designed to take
man to the edge of space.
VOICE TWO:
The X-15 flies high over the sandy wasteland of California's
Mojave Desert. Up, up it flies. After three minutes, its fuel has
burned up. It is flying about 2000 kilometers an hour.
Scott Crossfield's voice tightens. His breathing becomes harder
as the plane pushes against the atmosphere. At that speed, the
pressure is three times the force of gravity.
Then the X-15 pushes over the top of its flight path. It settles
into a long, powerless slide toward the landing field at Edwards Air
Force Base.
Designers of the X-15 have warned Crossfield about the landing.
They say it will be like driving a race car toward a brick wall at
160 kilometers an hour, hitting the brakes, and stopping less than a
meter from the wall. Crossfield lands the plane without any problem.
His success shows, as one newspaper reports, that "The United States
has men to match its rockets. "
VOICE ONE:
That first flight of the X-15 took place in September, 1959. But
the story began in the nineteen-forties with the 'X' series of
experimental aircraft.
The first plane ever to fly faster than the speed of sound was
the X-1 in 1947. United States government agencies and America's
airplane industry realized then that it was possible to build an
even faster plane. It would reach hypersonic speeds -- five times
the speed of sound.
The first proposal for this new research vehicle, the X-15, was
made in 1954. The space agency, Air Force and Navy jointly supported
the program. They wanted a plane that could test conditions for
future flights into space.
VOICE TWO:
The project moved quickly. The North American Aviation Company
won the competition to design and build the plane. The design would
be part aircraft and part spacecraft. The company took less than
four years to produce three X-15.
The planes were not big. They were just 15 meters long with wings
less than 7 meters across. They were designed to fly at speeds up to
6400 kilometers an hour. They were designed to reach heights of 80
kilometers. Their purpose was to explore some of the problems of
manned flight, during short periods, in lower space. No one had ever
done that before.
VOICE ONE:
The X-15 project had four major goals.
It would test flight conditions at the edge of Earth's
atmosphere. It would leave the atmosphere briefly, then return,
testing the effects of the extreme heat of re-entry. It would
provide information on the controls needed in the near weightless
environment of lower space. And it would answer a very important
question. How would humans react to space flight.
VOICE TWO:
The X-15 was a new idea. And it was built with new methods. It
was covered in a new material called "inconel x." The material was a
mixture of the metals nickel and chromium. It would protect the
plane from high temperatures.
There were new designs for the plane's rocket engine, landing
equipment and the small rockets needed to move it in space. There
was a new system of liquid nitrogen to keep the pilot cool and to
resist the crushing force of gravity at high speeds. And there was a
new fuel, a mixture of liquid ammonia and liquid oxygen.
VOICE ONE:
The X-15 was never designed to go
into orbit. Nor could it take off from the ground. It was carried
into the air by a B-52 bomber. The big B-52 carried the small X-15
under its wing. It looked a little like a mother whale swimming with
its baby.
At about 15,000 meters, the B-52 released the X-15. After a few
seconds, when the X-15 was safely away, the pilot started its rocket
engine. The X-15 flew upward with unbelievable power.
VOICE TWO:
The three X-15 were flown 199 times. Each flight was a new
experiment. Planning took many days. The pilot spent 50 hours in a
simulator -- a copy of the plane on the ground -- preparing for his
ten-minute flight.
Once the real flight began, the pilot had to remember everything
he learned. He had to work quickly and exactly. All his movements
were made against a force that could reach six times the power of
gravity. He had to struggle to reach forward for the controls while
being pushed back hard in his seat.
A delay of even one second could affect the information being
collected. It could change the plane's path just enough to destroy
the pilot's chance of a safe landing.
VOICE ONE:
The X-15 set height and speed records greater than those
expected. The number three plane climbed more than 107 kilometers
above the earth. The number two plane flew 7,232 kilometers an hour.
That was more than seven times the speed of sound.
The X-15 was the first major investment by the United States in
manned space flight technology. Much of what was learned from its
flights speeded up the development of the space program.
VOICE TWO:
The X-15 tested materials for space vehicles. It tested
spacesuits worn later by America's astronauts. It tested instruments
for controlling a vehicle in the weightlessness of space. And it
proved that experienced pilots had the skills necessary to fly in
space.
Twelve military and civilian test
pilots flew the X-15. A few became astronauts.
The X-15 program lasted about ten years. There were about 200
flights. Some of the flights carried scientific experiments. One was
a container on the end of the wing. It gathered dust and tiny
meteoroids from the edge of space. Another was a set of special
instruments that helped measure the effects of the sun's radiation
on the outside of the aircraft.
VOICE ONE:
The only tragedy connected with the X-15 program happened in
1967. The pilot was Michael Adams of the United States Air Force. It
was his seventh X-15 flight.
Everything, at first, appeared to be normal. The plane reached a
height of 80 kilometers. It was flying more than five times the
speed of sound. Then, during a test of the wings, the plane moved
sharply off its flight path. It dove toward Earth at great speed,
spinning rapidly out of control. Atmospheric pressure was too great
for the plane. It broke apart. The pilot did not survive.
VOICE TWO:
The X-15 made its last flight in December, 1968. NASA needed
money for its other projects. It decided to end the X-15 program.
Many space experts disagreed with the decision. They felt the X-15
could have continued to provide new information about aviation and
space.
Today, the X-15 hangs in the Air and Space Museum in Washington,
D-C. It is in a memorial called Milestones of Flight. In the
memorial, there is the X-1, the first airplane to fly faster than
sound. And there is the "Spirit of Saint Louis," which Charles
Lindbergh flew alone across the Atlantic Ocean. There also are
copies of famous spacecraft like Russia's Sputnik and Pioneer Ten.
On the floor below these aircraft are three spacecraft command
ships. One of them, the Apollo-Eleven, traveled to the moon just
seven months after the last X-15 flight. It carried the man who
became the first human to step on the moon, Neil Armstrong, a former
X-15 pilot.
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ANNCR:
This Special English program was written by Marilyn Rice
Christiano. Your narrators were Doug Johnson and Frank Oliver. Join
us again next week for another Explorations program on the Voice of
America.