The "H-IIA Rocket Overhaul" was carried out to learn lessons from the failure of H-IIA No. 6. It was a project in which engineers who engaged in [the H-IIA] rocket development worked together beyond company's boundaries to resume launch activity with H-IIA No. 7 as quickly as possible. One of approaches Mr. Yukimoto Nimura, who played the central role at Mitsubishi Heavy Industries, treasured was "know why" which was inspired from "know how." What is "know why" that is considered critical in manufacturing? Mr. Nimura, Executive Officer and Fellow of Mitsubishi Heavy Industries, who is also the H-IIA/H-IIB launch mission director explains in this interview.
Why "know why" not "know how"?
The common definition of know-how is wisdom, a procedure, or an empirical rule as to "this is how you can do it better." It is something like a manual that associates an action to success. In manufacturing know-how guarantees a certain quality of the product.
What is know-why?
While know-how is to inherit the answer to "how to do it?" know-why is to inherit the answer to "Why is it this way?"
From 1970s to 1990s N-II rockets were developed while N-I rockets were being launched. While N-II rockets were launched H-I rocket development was underway. As soon as H-I rockets were launched, H-II rockets were standing-by [for launch]. It was a time of a development boom, when multiple rocket series were developed one after another. When H-II rockets evolved to H-IIA rockets, the space between development programs became longer as the technology had matured and reached a certain level. As a result, young engineers who were assigned to new development projects had no knowledge of the history of launch vehicle technology.
A younger generation tends to think, "The current design is successful. We can use it "as is" in the next project." or "The newest version of this component is better. We should switch to it." Localized optimization might result in loss of overall system balance unless "why" a particular component is used for a particular purpose is understood from the overall system-level perspective. Why did we arrive at this design with what technical backbone? Not knowing why it is what it is, means throwing away insight and experience predecessors accumulated in the process of arriving there.
Nimura: "Here is a simple example. When you try to remove the sheath from a metallic cable, you may damage the cable when you use this tool and peel it off this way, but wrapping the cable with a tape will let you remove the sheath nicely. This is know-how. Why does wrapping [the cable] with tape work better? Would a rubber band [instead of a tape] work as well? Is this the right tool? Asking these questions is know-why."
Numerous tests and validations, trial and error, methods of analyses; many processes affect the outcome. With know-how, the procedure to make it successful will be conveyed, but it means the procedure cannot be changed. We do not believe that all we need to do is to pass the same technology down. We want to evolve it to make it better. Transformation requires the "why" question to be passed down. It is not easy to hand down know-why. Know-how can be translated to a manual but it is nearly impossible to record each and every question [to hand down "know-why"]. At this point, all what we can do is to orally convey "know-why" to younger generations.
Nimura: "That's why you have to keep asking "know-why" when designing. When you have a question, you should go to someone who has the answer right away."
The current rocket development environment is becoming unforgiving of any failure and young engineers tend to seek know-how that leads them to successful [completion of their tasks] directly.
Mr. Nimura keeps telling them, however, "What you need is know-why, not know-how." In such a demanding, high-pressure environment we should not waste the experience of our predecessors, he thinks.
Nimura: "Eventually, I think rockets should become industrial products. Current rockets are complex, special products requiring a specialized development environment and a large investment. Everything including its design and components must be fundamentally changed to transform [the rocket] to an affordable industrial product that can be assembled by less skilled technicians. It would be impossible to achieve this goal unless we understand "why is it this way?" or the core of technology.
I truly wish we will achieve it with the next H-III rocket. We will see how it goes." (Smile)
Power of Team in Rocket Making
Basically, there is nothing we can do [to a rocket] once it is launched, with the exception of one thing; that is to send the self-destruction command. In order not to destroy the rocket, [or to admit the failure of the launch], the team must be able to confidently say that we have done everything we could do while the rocket is still on the ground.
Nimura: "I would say it is more like conviction rather than confidence. Unless I know for sure that there is nothing more I could do, I would not go for launch. It is in a way "self-satisfaction". Every single person in the team including those who make small parts of the rocket has to have this conviction, not just me."
The H-IIA rocket's consecutive successful launch record is the result of the contributions of many people of JAXA, Mitsubishi Heavy Industries, and partner companies who were involved in the development, as well as the design, procurement, manufacturing, QA/test, accounting and sales groups.
Mr. Nimura started a program to invite those who are involved in manufacturing of H-IIA rocket components to the rocket assembly floor and ground firing tests. He wants them to see first-hand how what they made is used, in a tremendously large machine called a launch vehicle.
Nimura: "I want them to feel how critical their products are. I want to share with them the joy of successful launches, thanks to the parts and components they made. I think it is better that they feel they are contributing to the success. It motivates them better. Through a program like this, I hope they think, "We are going to make even better parts and components for our rocket." It is what I hope for the [extended] team."
This philosophy is convincing when converyed by Mr. Numura who put so much effort into creating the cross-organizational team in the "overhaul" project after the [failure] of H-IIA No. 6.