Difference between revisions of "Saturn Engine Cracks"

From Lunarpedia
Jump to: navigation, search
m
(No difference)

Revision as of 11:34, 18 August 2008

Apollo 09 David Scott podczas lotu Apollo 9 GPN-2000-001100.jpg This article is a Historical Essay
Written and submitted by
[[Grady Woodard]].


Grady’s Space Chronicles

SATURN ENGINE CRACKS

Just two days before my thirty-third birthday, I recall this huge problem as a young engineer working in MSFC’s Manufacturing Engineering Laboratory, Planning and Tool Engineering Division; Planning & Engineering Branch’s Engine Unit, I was assigned to the Rocket Engines, Cape Launch Coordinator, Explosives and other collateral duties.

On Wednesday, July 18, 1964, after arriving at my office about 6 AM, my phone was ringing and I picked up. It was Jim Fowler and Dr. Albert Zeiler, of Dr. Hans F. Gruene’s Cape Launch Operations Office. Zeiler said, “We have lost the purge on Pad B for Saturn SA-7’s Outboard Engine at Position Six. The leak is coming from a crack in the LOX Dome Plate below the inlet elbow, what are you going to do?” I told them the engine will be replaced, we have a spare ready to go!

The Oxidizer (LOX) Dome encloses the forward end of the thrust chamber combustion area, behind the injector plate and provides a mount for gimbal and thrust chamber assembly. It transmits engine thrust forces to the vehicle structure. The LOX from the turbo pump enters the thrust chamber through the elbow of the Dome Assembly. The Oxidizer’s flow rate is 526 lb/sec (3330 gpm). The force was so great that flow fins had to be placed inside the elbow to help direct LOX to the top of the injector, so an even force could be applied and achieve a good thrust burning pulse. The elbow is also the takeoff port of the gas generator oxidizer bootstrap line.

Zeiler conducts a series of engine tests. A nitrogen purge of the LOX Dome, located at the top of the H-1 engine, serves several purposes. A low-level purge, begins prior to propellant loading and continued until shortly before engine ignition, exceeded atmospheric pressure to prevent contaminants from entering the thrust chamber nozzle and flowing up to the injector plate and LOX Dome. This also prevented moisture from condensing in the area. If a launch was cancelled, a full-flow nitrogen purge would quickly expel all LOX from the Dome to avoid a possible explosion. Similar purges of the liquid-propellant gas generator, LOX injector manifold, and the fuel-injector manifold of the thrust chamber prevented the entry of unwanted substances.

A short time later, another phone call from Dr. Albert Zeiler was received, four more engine Dome leaks were found with the same problem. I pushed the panic button. An urgent meeting was called at MSFC for the next morning at 9 AM. All of the eight engines were ordered removed for failure investigation. It takes ten hours for an engine removal. The first engine arrived about 6 AM the next day and the LOX Dome was immediately removed for investigation on July 19, 1964. I had photos made for the urgent conference meeting.

The 9 AM Conference was scheduled at the Industrial Operation Director Robert B. Young’s seventh floor Conference Room in the new Building 4201. Present was the Rocketdyne Engine Contractor Mangers and Engineers, the Cape Director and his Staff was present as well as the MSFC Staff and Laboratory Directors and their Staff, with Dr. von Braun. Seated at the large Conference table were the Directors, behind each Director, to the wall, was their rank and file engineers. There was some standing where space in the room was available.

NASA had a problem in hiring a qualified Executives for the Director of Industrial Operations as it dealt with awarding and monitoring contracts with the space industry. The Pentagon had continuously loaned Procurement Officers to MSFC until NASA could find someone to work for low wages. On August 21, 1963, Mr. Robert B. Young, the Executive Director of Aerojet General, was loaned to NASA to head the MSFC Industrial Operations. Mr. Young was to serve for one year, he arrived on November 6, 1963.

Mr. Young, Chaired this important conference meeting with the Directors at the table, trying to work the Dome problem. When the discussion at the table needed detail information, the Directors would turn and asked the chair behind him, and they would ask down the rank and file (about four deep) until the correct response was sent back up to the table. It was an experience I will never forget, the organized procedure to speak with authority was seated at the table itself.

Many discussions had been made with a short lunch break and at 2:35 PM, a request came from the wall to the Director of Propulsion and Vehicle Engineering Laboratory at the table. He looked back and asked a question down to the wall and a response was returned to him. A repeat and a return, finally, the Director said, “Mr. Young, my young Metallurgist Engineer, Dr. Charles Cataldo, would like to have one of the cracked LOX Domes and cross section it (cut it up) and analyze it for failure investigation.” I worked with Dr. Cataldo and knew he just received a new 4,000 power electronic microscope for research.

A loud objectionable response was made around the table, for that would destroy the evidence specimen. Technical Assistant, Konrad Dannenberg, from the Research and Development Office of Director Hermann K. Weidner, stated, “One can not solve the problem if one don’t know what caused the problem?” Mr. Young stated, “Does anyone else have an alternative idea?” After a long pause, Mr. Young said, “Let’s give Dr. Cataldo until tomorrow at 2 PM, when we can meet again“. Let’s give Cataldo a chance”, he added.

Then no one said anything until Dr. von Braun (who spoke freely in meetings) said, “Shall we do this?” Meeting members agreed and Mr. Young ordered my Lab to give a specimen to Dr. Cataldo. I returned to my Lab as other cracked engines were arriving and transferred a cracked Dome to Cataldo‘s Lab. I provided and assisted Dr. Cataldo with manufacturing lot data for Domes and a spare Dome of a different lot. I worked with him until 8 PM. Dr. Cataldo worked all night and made many calls to the engine manufacturer Rocketdyne’s West Coast Operations Plant, where the LOX Domes were cast in molds.

Cataldo looked worst for wear at the 2 PM meeting, he was asked to make his report. Cataldo explained the cause of the cracks was the when the castings were cooling in the molds, the cooling effect caused the metal molecules to lock-in with the Earth’s magnetic direction of the North Pole. Molecules with the elbows pointing North, locked-in “end to end” was very strong. The molds where the elbows were not pointing to the North Pole, were cracking from metallic “stress corrosion” during working loads because of the misalignment of the molecules. Data was compiled showing the cracked Domes were from the same production batch lots, where molded elbows were not pointing to the North Pole. He recommend moving all the molds so the elbows will be aligned pointing North.

The table was buzzing from group talks, members were amazed by Cataldo’s report findings and his recommendations. Mr. Young called the meeting to order saying, “Shall we act on this recommendation?” after a pause, Konrad Dannenberg said, “I agree with the recommendation, but we should make twelve new Domes with the elbows mold casting aligned with the North Pole and Cataldo test three of them.”

Following discovery of "stress corrosion" cracks, all eight engines were removed from the SA-7 vehicle's first stage and sent back to Rocketdyne where aluminum alloy Domes were substituted (Reference: C. E. Catlado, P&VE Lab., H-1 Engine LOX Dome Failure).

The Domes molded in the North Pole direction arrived and tests were made, it was affirmed that the elbows were very good. All of the engines were repaired and tested at the Rocketdyne’s plant in Neosho, Missouri, with aluminum alloy Domes. My new H-1 Engine Transporter design worked very good for this project. The Engines were shipped to the Cape and installed on SA-7. All tests were good.

Meanwhile, the Cape was hit by two mid-September Hurricanes while waiting for engines, Cleo hit on August 28, 1964, with 110 mph winds followed by Hurricane Dora. SA-7 was safe inside the service structure. A surprised visit on September 15, 1964, by President Johnson ,coincided with the first countdown test after repair. All the problems delayed launch of SA-7 until launch on September 18, 1964. It was a very good launch and all goals were met to orbit a test Apollo Spacecraft in the final Saturn I R&D Test Flight series. Reasons for the Engine “Pop” during launch of Outboard Engine 5015 (Pos. 3) is unknown. SA-7 had the first flight computer that could updated from Earth.

Mr. Young’s return to Aerojet was in October, 1964. Mr. Young’s expertise in handling such a major problem was a great achievement and points to the need for a top experienced executive. We were thankful to Aerojet General for Mr. Young. The heroes of this story were Robert B. Young, metallurgist Dr. Charles E. Cataldo, who still lives on top of Monte Sano Mountain in Huntsville, Alabama, and Konrad Dennenberg, 96, still lives on his horse farm in Madison, near Huntsville, Alabama. After retirement, Konrad enjoys being involved with Space Program visits, involved in MSFC’s History Projects, the Astronauts and talking about Space.

After Aerojet received the enormous contract for the engines for the Titan ICBM, Young was named vice president and resident manager of the company's new Sacramento operation. In 1963, von Braun "borrowed" Young for a period to act as a consultant in the development of the engines for the Saturn boosters (the contracts for which had gone to Aerojet's rival, Rocketdyne). Young then returned to Aerojet to supervise development of the SPS engine (used to return from the moon) for the Apollo lunar spacecraft. He was born September 23, 1917, and died February 7, 1979.

I learned a lot working with this project. It seems we had historical problems all the time. Everyday developments occur and working ten to twelve hour days were routine for me because of my assignments and work load. Problems with logistical support at all levels as well as testing and hardware designs were very demanding and had to be solved.

Keeping research going and developing lab apparatus designs (black boxes) to produce science data was my strongest skill. I had great resources I provided myself from left over materials from other project engineers (raiding the junk yard was a weekly thing for me). I always could meet my deadlines and solved problems. Taking personnel responsibility to not be the one at fault to kill someone. I kept asking myself, “Would I ride this thing?” I hoped that other rocket team members have this same desire. I was told by coworkers that I was attending “Dr. von Braun University,” learn well!