Retour vers le futur : la NASA test les moteurs de Saturn en 2013

BREAKING NEWS - NASA Tests Saturn Engine Components With Eye Toward SLS
Aerospace Daily & Defense Report Jan14, 2013 , p. 1.01
Frank Morring, Jr.

Engineers at NASA ’s Marshall Space Flight Center are collecting data on kerosene-fueled rocket
engines by hot-fire testing a gas generator built from 40-year-old
parts originally manufactured for the Saturn V Moon rocket .
Testing
in a modified stand is planned to feed work underway that could lead to
a reprise of the old F-1 engine as the booster powerplant for the
agency’s planned heavy-lift Space Launch System (SLS).
Eleven tests
are planned, using hardware that had been put on display or in storage
after the Apollo program was canceled, including an engine warehoused at
the Smithsonian Institution that was originally build for the Apollo 18
mission that never flew. Running either 5 or 20 sec. each, the tests
are helping young NASA engineers gain experience on hydrocarbon-engine
technology. Data generated by the tests will be used by a Pratt &
Whitney Rocketdyne/Dynetics team that is working on modern manufacturing
techniques to produce a more affordable F-1 for possible use on the
SLS.
NASA used optical scanning to generate computer-aided design
(CAD) drawings of the parts, which were originally designed on paper.
Those CAD files will help NASA and the contractor team apply modern
analytical techniques to produce better data on the component
performance than was possible when it was built by North American
Aviation’s Rocketdyne Div.
The last two tests are designed to gauge
combustion stability in the gas generator, which uses a little of the
propellant to power the turbomachinery that feeds the main combustion
chamber. Future testing could include the addition of the turbomachinery
and perhaps even a combustion chamber to produce a breadboard engine
based on the F-1.
“The reason we started with the old hardware is it
exists,” says Ralph Coates, lead discipline engineer on SLS advanced
development at Marshall . “We don’t have to go out and procure it. We
own it.”

Imagine a young engineer examining an artifact from the Apollo era that
helped send people on humankind’s first venture to another world. The
engineer has seen diagrams of the rocket engine. She has even viewed old
videos of the immense tower-like Saturn V rocket launching to the moon.
Like any curious explorer, she wants to see how it works for herself.
She wonders if this old engine still has the "juice." Like a car
mechanic who investigates an engine of a beloved antique automobile, she
takes apart the engine piece by piece and refurbishes it.



This is exactly what a small team of young NASA engineers did. The
engineers, who have been trained in fields from rocket propulsion to
materials science, took apart and refurbished parts from Saturn V F-1
engines--the most powerful American rocket engines ever built. Why
resurrect an Apollo-era rocket engine? The answer is simple: to mine the
secrets of the F-1 -- an engine that last flew before these engineers
were born -- and use it as inspiration for creating new advanced,
affordable propulsion systems.



NASA needs powerful propulsion elements for future launch vehicles, such
as the evolved Space Launch System (SLS). The SLS heavy-lift rocket
capable of carrying a 130-metric-ton (143-ton) payload is being
developed by NASA's Marshall Space Flight Center in Huntsville, Ala. The
advanced booster required for the heavy-lift rocket will be completed
in 2015.



"When we started examining different types of propulsion systems capable
of lifting a rocket as large as the SLS, we pulled F-1 engine drawings
and data packages and studied an F-1 engine that we had on hand at
Marshall," said Nick Case, an engineer from Marshall’s Engineering
Directorate’s Propulsion Systems Department.



The team decided to take apart the gas generator, the part of the engine
responsible for supplying power to drive the giant F-1 turbopump. The
gas generator components were small enough to be tested in Marshall’s
laboratories, and the gas generator is often one of the first pieces
designed on a new engine because it is a key part for determining the
size of a rocket engine. The team removed one gas generator from an F-1
engine stored at Marshall and from another that was in almost pristine
condition because it was stored at the Smithsonian National Air and
Space Museum in Washington. They cleaned the parts and used a novel
technique called structured light 3D scanning to produce
three-dimensional computer-aided design drawings.



"This activity provided us with information for determining how some
parts of the engine might be more affordably manufactured using modern
techniques, such as additive manufacturing," said Kate Estes, a Marshall
liquid propulsion systems engineer. "We decided that using modern
instrumentation to measure the gas generator’s performance would provide
beneficial information for NASA and industry." The team used selective
laser melting, a digital manufacturing technique for producing metal
parts quickly, to create new parts needed for the test and to determine
the hot gas temperature and pressure inside the test article.




The F-1 also was studied because it burns liquid oxygen and refined
kerosene. NASA's youngest generation of engineers does not have as much
experience with engines that burn this fuel mixture. Current NASA and
aerospace industry experts are most familiar with propulsion systems
such as the Space Shuttle Main Engine and the new J-2X engine, which
burn liquid oxygen and liquid hydrogen.



"Being able to hold the parts of this massive engine that once took us
to the moon, restoring it, and then seeing it come back to life through
hot firings and test data has been an amazing experience," Estes said.



Now the team is conducting a series of hot-fire tests on Test Stand 116 in Marshall’s East Test Area.



"We modified the test stand to accommodate a single kerosene gas
generator component," said Ryan Wall, the test conductor for the series
of ten tests. "These tests demonstrate the stand’s new capabilities,
which will be beneficial for future NASA and industry propulsion
activities."



The most noticeable aspect of these firings is the sheer power when the
gas generator ignites and creates roughly 31,000 pounds of force. When
the original F-1 lit up, the gas generator powered the giant
turbomachinery that pumped almost three tons of propellant each second
into the thrust chamber and accelerated through the nozzle, creating the
incredible 1.5 million pounds of thrust.



"Modern instrumentation, testing and analysis improvements learned over
40 years, and digital scanning and imagery techniques are allowing us to
obtain baseline data on performance and combustion stability," Case
said. "We are even gathering data not collected when the engine was
tested originally in the 1960s.” Since NASA conducted this work
in-house, the data are not proprietary and will be shared with industry
partners and academic researchers.



"This effort provided NASA with an affordable way to explore an engine
design in the early development phase of the SLS program," said Chris
Crumbly, manager of the SLS Advanced Development Office. "NASA’s young
engineers are gaining valuable knowledge working with one of the most
powerful engines ever built, and the SLS program will benefit from data
that will bolster our efforts to reduce risk and enhance the
affordability as we develop an advanced heavy-lift booster capable of a
variety of missions."



The larger, evolved SLS vehicle will require an advanced booster with
more thrust than any existing U.S. liquid- or solid-fueled boosters.
Last year, NASA awarded three contracts aimed at improving the
affordability, reliability and performance of the rocket’s advanced
booster. Dynetics Inc. of Huntsville, Ala., working with their
propulsion subcontractor, Pratt & Whitney Rocketdyne of Canoga Park,
Calif.-- the company that developed the F-1 engine--will use these
early tests as a springboard for more gas generator testing at Marshall.
Then, they will use modern manufacturing to build a new gas generator
injector that also will be hot fired in Test Stand 116 and compared to
baseline data collected during the earlier test series. Additionally,
Dynetics’ activities include fabricating and testing several other F-1
engine parts, such as the turbine blades, culminating in testing of an
entire F-1B powerpack including the gas generator and turbopump, the
heart of engine operations.



ATK Launch Systems Inc. of Brigham City, Utah, will examine innovations,
such as composite cases, for solid-fueled boosters. Northrop Grumman
Corporation Aerospace Systems of Redondo Beach, Calif., will explore
design and manufacturing techniques for composite propellant tanks.