Recently I visited old colleagues at NASA’s White Sands Test Facility. The Orbital Maneuvering System tanks, removed from Discovery, were sitting in the dirt, ready to be cut up and disposed of. The toxic rocket fuel they held for most of their lives makes cleaning those tanks impossible, and it would be a hazard to museum goers to be exposed to fumes from residual rocket fuel hiding in those tanks. So disposing of those high tech, precision built tanks is sad but necessary.
At an early point in my career at NASA I cared a great deal about the function of those tanks. Because I was responsible to know how much gas was in the tank.
The gas gage on the shuttle never worked. Think about it; the gas gage on your car depends on gravity to keep the fluid in an orderly manner in the bottom of the tank. In space, in microgravity, blobs of fluid just float around inside the tank. How do you measure that? Even more important; how do you get the fuel to the rocket engine? In the Orbital Maneuvering System that question was answered by building in a fine mesh screen: double dutch twill weave. The surface tension of the liquid would keep the gas out and fuel in where the pipe exited from the propellant tank. But reusable tanks brought the concern that those screens could be damaged by vibration or shock during flight. Periodically between flights the screens were tested using a “bubble point” device. A good pressure check with no bubbles meant the screens had no holes and were working properly. Those bubble point tests were done at White Sands. Thereby hangs a tale.
Removing the OMS pods and shipping them to WSTF was a real logistical nightmare. Somebody had the bright idea to move the bubble point testing equipment to KSC so the test could be performed without moving the pods. Brilliant! Until we ran into the standards issue.
For space flight hardware, the Shuttle program specified the standards used in the design, development, testing, and production. But for ground test equipment, the space center where the equipment was used was responsible for the standards. You might think that NASA would have a set of standards for things like welding a pressurized metal tank used in ground checkout of space flight hardware. But if you thought that you would be wrong. Much of the time NASA appears to be a loose confederation of 10 quasi independent fiefdoms, each pretty much in charge of their own business. People often ask me what would I do if I were king of NASA for a day. They expect me to say something like: build this rocket, launch that satellite. Rather I think how I would standardize the procurement processes, or the human resources procedures, or the engineering standards used across the agency. But then I always was a dreamer, tilting at impossible windmills. Launching rockets is easy; getting engineers to agree on standards is hard.
Back to our story . . .
The WSTF had build the OMS tank screen bubble point testing equipment to the center recognized standard for welding pressure vessels. I don’t remember whose standard that was, but it was a nationally recognized standard; let’s say it was a standard of the American Society of Mechanical Engineers. A good standard. A recognized standard. But not the only standard.
At the Kennedy Space Center, they use a different standard; I don’t remember which one, but let’s just say it was the standard of the American National Standards Institute. Now I’ve probably gotten it wrong, but that is just the illustration. Another standard; equally recognized, equally good.
Unless you are a welding standards expert. At KSC, as at every center, a Technical Expert is responsible to see that all hazardous equipment is built to their standards
Moving an ASME certified piece of hardware to the ANSI requiring Kennedy Space Center turned into a herculean job. The KSC Technical Expert would NOT approve its use. Some obscure, arcane difference existed between the standards that he never completely explained to me. A poor program manager could not overrule the Independent Technical Expert, only the Center Director could do that. So no matter how much we cajoled, persuaded, pleaded, accepting the equipment was a non-starter. The Center Director said it was important to show support to his Technical Expert.
So what were we to do? Continue the costly and somewhat dangerous practice of sending OMS tanks half way across the country? Stop doing a necessary safety check of the screens and risk stranding astronauts in orbit some day? Build a new set of test equipment with the KSC required standard which would be a complete waste of the taxpayer’s money? Or. . . accept a waiver.
The program manager had to sign a waiver to the requirement saying that we, the program management, accepted the risk of using non-standard equipment. Yes, we were evil, blind to the risks involved, interested in only schedule and cost. Or so you would think if you read the waiver description.
Small price to pay to get on with business, save money, eliminate other hazards. Honestly, I never understood what the argument was about. I think it was really about control.
So these days I read the NASA procurement request for the new Commercial Crew vehicles, and see that there is a long list of specifications that the companies must use. Almost all of them have the notation that the bidder could propose using a different standard if they are willing to prove to the NASA Technical Expert that the proposed standard “meets or exceeds” the NASA requirement.
And I think about that OMS bubble point equipment and wonder why we are making companies tilt at impossible windmills. Building the rocket is easy. Getting agreement on standards between engineers is hard.