de John Stott
"Apollo Test Operations, as I remember"
John Stott worked for NAA as an ATO (Apollo Test Operations) engineer at MSC during the CSM-008 and 2TV-1 manned test.
NAA Identification Badge of John Stott (circa 1968).
"I was employed by North American Aviation (NAA) at the Columbus Ohio Aircraft Division during the early 60’s as a Design Engineer. NAA was awarded the major contract for the Apollo Spacecraft (SC), Service Module (SM) and systems, Grumman the Lunar Excursion Module (LEM). Space was a hot item and NAA was allowing a few of its engineers to transfer to the newly formed Space and Information Division (S&ID). I managed to get on the short list and was transferred to the Apollo Test Operations (ATO) at the Manned Spacecraft Center (later to be named the Johnson Spacecraft Center) as a Flight Test Engineer at Clear Lake, Texas. My transfer took place in July of 1965.
ATO Personnel for CSM-008 test.
In the beginning our responsibility was to activate the test site in preparation for the spacecraft and service module’s arrival from the S&ID facility at Downey. This effort was to install and check each individual item of Ground Support Equipment (GSE), to interface and integrate all of the GSE with associated telemetry and controls to the Automated Checkout Equipment (ACE computer), the Control Center and to the spacecraft in the thermal vacuum environmental test chamber. The site activation process took about six months of writing, performing, verifying and documenting the Acceptance Test Procedures (ATP). Each action was required to be witnessed by the initiating NAA test engineer, a NAA Quality Control Engineer, a NASA system engineer, and the NAA technician who actually did the work. In many instances photographic records were required.
2TV-1 Arrival by Super Guppy;
After arrival of the Apollo Spacecraft and Service Module from the S&ID plant in Downey California each Flight Test Engineer was responsible for executing the actual system tests performed on the Apollo SC/SM combination in the chamber. These tests simulated the environment of an actual mission, Block I simulated an orbital mission, Block II simulated a lunar mission. Of course we didn’t fire any engine or propulsion device in the chamber, but the environmental conditions were simulated. The difference between the two was the length of the mission and the equipment on board, the Block II vehicle had different systems onboard. Three test astronauts manned each test and perform the mission functions required by the CCL, CCC, and CCR (left, center and right couch positions). Photographs were taken with a 35mm stereo camera, which were especially important where detail work and configuration records were concerned.
Chamber preparation was a lengthy procedure in its self. After the spacecraft was placed on the test stand inside the chamber the test system was interfaced to the craft and chamber. This included cryogenic, hydraulic, waste management, life support, and electrical, electronic and physical means of stimuli/response and measurement of craft and mission parameters. After readiness verification the chamber was sealed and evauaction began.
2TV-1 CSM inside the Vaccum Chamber.
The evacuation process was a three-stage process. First there was a three-day roughing process. Roughing was accomplished by large positive displacement pumps that extracted most of the air from the chamber. It is important to note that an amount of dry air mixture that would re-pressure the chamber was compressed and stored in external tanks. This was for emergency chamber re-pressurization as the normal humidity of air combined with the sudden pressure change and the extreme temperatures could create undesirable weather conditions to occur inside the chamber. The next phase was accomplished by large diffusion pumps that reduced the pressure to near acceptable test levels. This required several days, depending on any microscopic leaks that might have developed in the chamber that had to be located and sealed. Out gassing of the spacecraft and other material also slowed the process. Additional pressure reduction was achieved by the cryogenic curtains in the chamber that simulated the cold of space. Any free molecules would freeze to the curtain and solidify. This also took care of out-gasing and venting of the spacecraft during the test and cooled the dark side of the spacecraft below –200 degrees Fahrenheit. The cryo curtains were vertical panels with liquid nitrogen and liquid helium circulating through them. Solar simulation was achieved by Schmidt optical systems. Forward and side banks of carbon arc lamps were arranged so that an endless supply of carbon rods would continually feed into the lamp as the carbon was used up. This energy was focused through the Schmidt optics onto the spacecraft skin heating it to above +200 degrees Fahrenheit. The chamber contained a turntable that provided the spacecraft rotation necessary for thermal control. Looking the photos of the spacecraft in the chamber white dots can be seen on the tubing which formed the test stand, these changed the thermal radiation coefficient making the test stand thermally transparent. In these same photos you can see the ‘pool table’ under the main engine nozzle of the service module, this thermally shielded the cabling and tubing that came through the floor of the turntable. Beneath the turntable these were coiled like a clock hairspring allowing the turntable to rotate one full turn.
When the accident occurred at Cape Canaveral a spacecraft was in position for testing. Immediately we set up conditions using the cape’s instrument records to duplicate what had happened. Of course we didn’t use a pure Oxygen environment, nor was anyone exposed to any danger. I was picked, having an electronic background, to design and fabricate a electronic switching device that would create electrical disturbances in the electrical systems that matched the spacecraft data at the moment of the accident. Another engineer was picked to design and fabricate a mechanical switching device. Test teams then performed exhaustive tests to duplicate and isolate the problem. Good engineering results were obtained, but nothing conclusive.
During this time, July 1965 to November 1968, most of the Flight Test Engineers filled different test functions as required. It was my privilege was to be assigned (in chronological order) to Site Activation, SC Sequential and Pyrotechnic Systems, SC Electrical Power Sequential Systems, and SC Guidance/Control Systems. After that I transferred back to the Aircraft Division at Columbus Ohio. In 1967 North American Aviation became North American Rockwell, in 1973 became Rockwell International, in 1996 a merger took place with Boeing and the space and defense divisions of Rockwell International."
John Stott, today.
"I transferred back to the Columbus, Ohio aircraft division of NAR around November of 1968 where I continued as a design engineer until 1973. At that time I became self employed until 1976. Then moved to Austin, Texas and was with Tracor Aerospace manufacturing test engineering department until December 1988. Then to The University of Texas Petroleum Engineering Department technical staff where I assisted students with laboratory and process instrumentation and control. Then I retired mid 1994. Prior to NAA/NAR/RI I served with the US Air Force, Collins Radio, Texas Instruments. I suppose that you could best describe me as a migrant aerospace worker."
Additional information, from E.mail correspondence :
"As a Flight Test Engineer we only interfaced with the Astronauts when they were in the chamber for an actual test. There was little or no personal contact. The names of the backup crew are vaguely remembered I but never saw them in person or in the chamber."
Visit John Stott hompage at http://hometown.aol.com/jcstott/
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© 2004, MaxQ Webmaster. All photographs have been provided by John Stott.