Historic Perspective of Apollo Technology
David DeFelice, 3-6186
issued by the NASA Lewis Research Center chronicling our contributions to
the Apollo mission. There are some interesting perspectives into the
technical and programmatic issues of that era. I hope that you do enjoy
this and remember all of those who labored to make the vision of Apollo a
reality.
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FOR IMMEDIATE RELEASE
Release 69-36
Charles E. Kelsey
CLEVELAND, Ohio, July 14 -- The Apollo program
has been described at various times by astronauts, engineers,
space agency officials and newspaper editorials as a
magnificent "team effort." Indeed, the team which is
accomplishing this complex program to explore the Moon
comprises hundreds of thousands of government and
contractor employees throughout the nation.
One member of the National Aeronautics and Space
Administration team, the Lewis Research Center, provided
important early research as well as subsequent direct
technical support to the Apollo program.
The Center's contributions included:
-- Pioneer research in rocket tests with liquid
hydrogen and liquid oxygen systems;
-- Engineering studies of tanks, lines, and liquefiers
for liquid hydrogen;
-- Wind tunnel tests of Saturn vehicles and of the
Launch Escape Subsystem;
-- Studies in the Zero Gravity Research Facility for
settling propellants in fuel tanks;
-- Technical consultation and advice in such areas as
safety, fuel cell performance, rocket engine combustion,
propellant pump design, and thrust chamber fabrication.
Among the shapers of history in the early years of
the space program was Lewis' present Director, Dr. Abe
Silverstein. In 1958, when he was Associate Director of
Lewis, Dr. Silverstein was called to Washington to help
organize NASA, which was, as the Successor of National
Advisory Committee for Aeronautics (NACA), to be the
nation's civilian agency for meeting the challenge of space.
Within the new agency, Dr. Silverstein was appointed
the Headquarters Director of Space Flight Programs with
responsibility for developing and initiating all space
missions. Many of those missions are going on today,
others such as Ranger and Mercury have ended.
Among the many missions conceived at that time
was a manned journey to the Moon and back. Dr.
Silverstein himself named it Apollo' after one of the most
versatile of the Greek gods. Dr. Silverstein recalls he chose
the name after perusing a book of mythology at home one
evening, early in 1960. He thought that the image of
"Apollo riding his chariot across the Sun was appropriate to
the grand scale of the proposed program."
When did the program originate? The idea of a lunar
mission was first officially introduced at a meeting of
NASA program planners in Nov. 1959 at Wallops Island,
Va. However between that time and President John F.
Kennedy's historic space commitment of 1961, much of the
basic mission remained to be worked out. During this time
Dr. Silverstein chaired the committee that determined the
characteristics of the Saturn family of launch vehicles,
including the use of liquid hydrogen-oxygen propellants.
Long before Apollo was ever planned or named, the
Lewis Research Center in Cleveland was advancing the
propulsion technology which would help make the mission
possible.
As early as the later part of the 1940's Lewis had
begun research on high energy liquid rocket propellants
under the direction of Dr. Walter T. Olson, now an
Assistant Director of Lewis, and by 1952 this work included
studies of liquid hydrogen-liquid oxygen.
Initial Lewis investigations used very small thrust
chambers in the range of 100 to 1000-lbs. thrust. Over the
course of the next decade, rocket engineers and scientists
experimented with a variety of thrust chamber designs to
achieve high combustion efficiency and smooth burning;
and they measured heat transfer rates within the thrust
chamber and demonstrated how to cool the chamber and
nozzle with liquid hydrogen. Since hydrogen, the lightest
of the elements, in its liquid state boils at -423 deg F, and the
oxidizer, liquid oxygen, is stored at -297 deg F, another major
concern was how to handle the cryogenic propellants
themselves.
By 1958, as the United States entered the space
business the Lewis Research Center had tested a fully
cooled, liquid hydrogen-liquid oxygen thrust chamber at the,
then large scale of 20,000 lbs. thrust.
The experience Lewis propulsion experts gained in
the field of high energy propellants later led to the
development of the 15,000 lb. liquid hydrogen-liquid
oxygen engine designated RL-10. Two of these engines
power the upper stage of the Atlas-Centaur launch vehicle
that has been under Lewis management since 1962. (Atlas-
Centaur launched the Surveyor spacecraft that landed on the
moon, and the Mariner space craft that will fly by Mars on
July 31 and Aug. 5.)
Much of the same technology developed by Lewis
for Centaur was particularly applicable to the J-2 liquid
hydrogen-oxygen engines of the Saturn second stage (S-II).
Consequently a number of Lewis staff members --
men by then well experienced in high energy propulsion
systems -- were called upon by NASA Headquarters to
serve on the technical assessment teams which
recommended the contractor to build the F-l and J-2
engines. Dr. Silverstein chaired the Source Board which
made the final selection of the F-l contractor. Work began
on the F-l engine, the nation's largest, in 1958 and on the
J-2 in 1960.
During the course of development of these engines,
Lewis continued its technical support in the form of
consultation with NASA's Marshall Space Flight Center,
Huntsville, Ala. Melvin Hartmann and Ambrose Ginsburg,
Lewis fluid systems engineers, served on a Marshall
committee to review problems being experienced by the F-l
turbopump. These and other specialists served as consultants
on a J-2 review committee. Among the topics discussed and
of particular interest to the Lewis men was the inducer, that
component which draws the boiling cold hydrogen into the
pumps. Previous research conducted on this component at
Lewis' Plum Brook Station near Sandusky, O., helped verify
data of the Marshall Center that showed the inducers would
permit a desired low pressure in the fuel tank.
Lewis also assisted a Marshall task group in
achieving combustion stability in the F-l engine. Dr.
Richard Priem, experienced in advanced rocket combustion,
was one of this group studying the "rocket screaming", a
phenomenon caused by strong resonant pressure waves and
which can destroy a rocket engine in seconds. One other
area of consultation with Marshall during the F-1 develop-
ment was on fabrication of the thrust chamber. Walter
Russell, a fabrication specialist served on the committee to
review the materials and processes for the fabrication of the
furnace-brazed thrust chamber and its jacket.
Staff members also lent their technical knowledge to
other areas of the Apollo propulsion systems. Early studies
were conducted at Lewis on the type of storable propellants
to be carried on the upper stage of the Saturn V vehicle and
on the spacecraft.
The Center's unique Zero-Gravity Facility was called
upon to do two jobs for the Apollo program. In mid-1960,
engineers used this facility to help solve the problem of re-
starting the Service Module's propulsion system in space.
Using surface tension phenomena observed during these
studies, Lewis engineers assisted in designing a retainer for
the propellant in the fuel tank. This retainer would keep
enough propellant at the bottom of the tank to ensure that
propellant would enter the pump and re-start the engine.
The Zero-Gravity Facility was used to help solve a
similar problem in the SIVB third stage of the Saturn V for
the Marshall Center. In flight when the SIVB engine shuts
down, auxiliary hydrogen-peroxide thrusters are turned on
to settle the sloshing propellants. During the coast phase
the propellants are maintained in the bottom of the fuel tank
by the thrust obtained when boiled off hydrogen gas is
ducted through a small thruster system. Studies in the Zero-
G Facility were able to determine the proper size of these
various thrusters.
One of the astronaut's concerns about how
weightlessness in space might affect fuel cell performance
drew helpful information from Lewis too. Fuel cells are
carried aboard the Service Module to provide electric power
to spacecraft systems. Consequently, Lewis researchers
investigated this area and made known to the Manned
Spacecraft Center that the condenser of the fuel cell did not
depend on gravity to operate properly. Lewis also was
asked by MSC to determine the heat transfer characteristics
of the condenser; this information was used in a computer
simulation of the spacecraft's electrical power subsystem.
During 1967 Lewis engineers were consulting on the
overall combustion and system stability of the Lunar module
ascent engine, the critical propulsion system for the Ascent
Stage which returns the astronauts from the moon to lunar
orbit. John Wanhainen, a chemical rocket expert, was part
of a task group to overcome the high frequency combustion
instability noted in the engine. Two other engineers, Robert
Dorsch and Leon Wenzel, ran analog computer analyses of
low frequency combustion instability characteristics.
The Center's 8 x 6-foot transonic and 10 x 10-foot
supersonic wind tunnels were used in extensive tests on
models of Saturn booster stages. The first such tests were
made in the late 1950's when engineers studied base flow
and heating tests on the SIB booster, the eight-engine first
stage of the Saturn I. The 1/45th scale model had real,
working rocket engines of 250 lbs. thrust each. Data were
taken over a range of speeds from takeoff to Mach 3.5 and
of altitudes from sea level to 150,000 feet. This simulation
of actual flight conditions provided valuable information on
the pressure and heat loads experienced on the base and
engines' compartment of the SI vehicle. By varying the
size and location of flow deflectors and shroud air scoops--
devices to channel the air to best advantage--engineers were
able to minimize the pressure and heating loads. Another
study on the SI helped optimize vehicle flight stability and
air pressure distribution.
In the 1964-1966 period base flow and heating also
were studied in both wind tunnels for the SI C first stage of
the Saturn V. Also, the force required to move the engine
nozzles for directional control had to be measured. These
measurements helped determine the size of the actuators
required to gimbal the engines. In all manned missions,
safety of the public, the astronauts, and the operating crew,
is a major concern to the NASA. In case a mission must be
terminated early, one of the first options the astronauts have
is to employ the Launch Escape Vehicle and Tower which
stands atop the Command Module. This escape system
propels the Command Module out and away from the
Saturn V. During 1964 tests were made on the system in
the Lewis Research Center's 8 x 6 tunnel at the request of
the Manned Spacecraft Center. In the tunnel, a model of
the escape system attached to the Command Module was
released at various angles to determine its stability under
simulated flight conditions.
Safety was the subject that brought I. Irving Pinkel,
now Lewis' Assistant Director for Aerospace Safety, to
serve as a consultant to the Apollo 204 Review Board. In
that capacity and as a member of the team which
investigated the causes of the spacecraft fire which took the
lives of three astronauts early in 1967, Pinkel helped to
recommend changes in the capsule to prevent a future
tragedy.
Through extensive consulting on fracture mechanics,
Lewis professionals have assisted in improving both the
more than 140 pressure vessels of the Saturn V, and the SII
fuel tank. Particular contributions by Lewis materials
scientists to the construction of pressure vessels included
improved test methods, and methods of design and analyses
used on new concepts in fracture mechanics technology.
Other materials scientists and engineers provided fracture
research data on the critical weldments of the SII fuel and
on the tank material itself; they also recommended
cryogenic proof tests, and suggested flight conditions to
reduce wind loads on the vehicle.
Thus, Lewis scientists and engineers, like thousands
of others who have served the Apollo team, have their
hopes riding high with Apollo 11.
#
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David M. DeFelice - NASA Lewis Research Center - Community Relations Office
(216) 433-6186 Cleveland, Ohio dav...@lims01.lerc.nasa.gov
___________________________________________________________________________
"Why can't life be menu driven or at least have an 'undo' feature?"
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Henry Spencer
>I thought that you all might enjoy reading the original 1969 Press Release
>issued by the NASA Lewis Research Center chronicling our contributions to
>the Apollo mission. There are some interesting perspectives into the
Such as the fact that the release was obviously written by a PR man, and
wasn't proofread by any of the technical people! It has at least two
technical errors... However, it was interesting all the same; thanks
for posting it.
--
SMASH! "Sayy... I *liked* that window."| Henry Spencer @ U of Toronto Zoology
"I enjoyed it too!" "Hmph! Some hero!"| he...@zoo.toronto.edu utzoo!henry
Henry Spencer
>...obviously written by a PR man... It has at least two
>technical errors... However, it was interesting all the same...
Well, several people have asked me to elaborate, so here goes...
>engineers used this facility to help solve the problem of re-
>starting the Service Module's propulsion system in space.
>Using surface tension phenomena observed during these
>studies, Lewis engineers assisted in designing a retainer for
>the propellant in the fuel tank. This retainer would keep
>enough propellant at the bottom of the tank to ensure that
>propellant would enter the pump and re-start the engine.
No pumps in the SM engine system! Still correct in essence, since
even a pressure-fed engine system like the SM's still needs to get
fuel, not pressurization gas, to function properly.
> The Zero-Gravity Facility was used to help solve a
>similar problem in the SIVB third stage of the Saturn V for
>the Marshall Center. In flight when the SIVB engine shuts
>down, auxiliary hydrogen-peroxide thrusters are turned on
>to settle the sloshing propellants...
Somebody mixed up Centaur and S-IVB here. The S-IVB auxiliary
propulsion system burned N2O4/MMH. Centaur did originally use
peroxide thrusters for this.
>...and heating tests on the SIB booster, the eight-engine first
>stage of the Saturn I...
This one qualifies as nitpicking... the S-IB was the first stage of
the Saturn IB. The Saturn I first stage was the S-I. The S-I and
S-IB were similar but not identical.