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Archives: Spring / Summer 1999 Table of Contents
A Life Weld-Lived
by Andrea Cohen, MIT Sea Grant

On a rainy spring morning, Koichi Masubuchi sits in his office eager to talk. He has spent a lifetime fusing connections, and though he is very much here, his mind also wanders off into space and underwater. That’s not surprising, because for the past fifty years, as Professor of Ocean Engineering and Materials Science at MIT, Masubuchi has been pioneering welding research in both those unfriendly realms.

Welding is, of course, a common means of using heat to join two pieces of metal for all kinds of applications. Traditional welding relies on an electric arc-a sustained electrical discharge across a gap in a circuit or between electrodes. Environments other than ordinary air pose significant problems in both construction and repair. In underwater "wet" welding, removing water from an area is particularly difficult. Starting in 1970, in one of MIT Sea Grant’s earliest funded projects, Masubuchi, students and colleagues used high-speed photography and analytical models to investigate the rapid cooling of welded materials underwater. From there, Masubuchi explored the development of systems for welding at greater depths, as well as automated systems for deeper waters and irradiated environments.

According to Masubuchi, it’s not a far leap from that underwater work to his development of welding technologies for space applications. Although his formal education in his native Japan was in naval architecture, Masubuchi was heavily involved, while working at the Battelle Memorial Institute in Columbus, Ohio, in developing techniques for welding fabrication of large fuel and oxidizer tanks in the Saturn V space vehicles used in the Apollo lunar missions. He later led an MIT research team that participated in the first U.S. space welding experiments in 1973 aboard Skylab. In 1983, his team conducted extensive research for NASA aimed at developing welding technologies to maintain and repair a space station to be built and operated in the 21st century.

Photo of an artist's conception of the International Space Station
Artist's concept of the International Space Station. A welded stainless steel pipe is inset on left; a GHTA arc operating in a vacuum is on right.

More recently, Masubuchi has been the advisor on a project headed by Yoshikazu Suita, a professor at Takamatsu National College of Technology (TNCT). In 1998, Suita was sent by Japan’s Ministry of Education to MIT for 10 months to advance his research. While working under Masubuchi, Suita became interested in space welding. Since returning to Japan, he has continued his research to develop a technique called the gas hollow tungsten arc (GHTA) welding process. With this method, a welding arc can be initiated even in the vacuum environment.

Since 1998, the Space Forum, a subsidiary of the National Space Development Agency of Japan, has been supporting research activities at TNCT to develop technologies for maintaining and repairing the International Space Station (ISS), an international cooperative construction project for a space port that will serve as a transfer point for personnel and cargo for deeper space exploration. Plans call for ISS to operate in space for some 30 years. During that time, structural damage from normal use and deterioration, accidents, or collision with debris will require repairs. Masubuchi is less worried about the catastrophic collision of intergalactic material than the ordinary problems with pipes such as wear and tear. "Think of a pipe being like an artery to your heart. If that breaks, you have a big problem," he says. Thus, the swift and effective repair of pipes in space is critical.

In the Space Forum program, researchers are studying the effects of gravity on welding by performing experiments aboard a diving airplane that creates space-like zero-gravity conditions for 20 seconds. In those brief periods, researchers have successfully made semi-automated welds of stainless steel pipes in a vacuum under near-zero gravity conditions. Further in-flight experiments are planned for 1999.

The fruits of this research may not be put into place for another 20 years. Yet, says Masubuchi, the work points out the need for "a new way of developing new technology simulation"-a kind of "virtual welding technology." Rather than expensive and impractical development via trial and error, welders would try out welding methods much as airline pilots try out flying scenarios in a flight simulator.

Virtual welding, says Masubuchi, will be key to narrowing the gap between the practical and the theoretical: between the welders and the thinkers. As a welding researcher, Masubuchi is a rarity, having actually worked as a ship fitter in Japan during World War II while a student in the department of naval architecture at the University of Tokyo. That background gives him a special appreciation for the skills needed in shipbuilding. That industry has seen steady declines in the United States in the last several decades as Japan, Korea, and then China offered highly skilled, cheap labor. He notes that advanced nations need to focus on developing capable welders to build equipment and repair structures in the next century.

And where does Masubuchi see some of this new welding taking place? He opens a notebook and displays an artist’s rendering of a floating airport. "There are many kinds of structures such as airports, nuclear reactors and prisons that are needed, but nobody wants them in their backyards," he explains. "We need to develop technologies for fabricating and maintaining structures to operate in unfriendly climates."

As to his own work, Masubuchi will continue to bridge gaps in space and underwater. He’ll serve as advisor on the Space Station Freedom for one more year. "I’m a person who’s curious," he says. "I’m 75 years old. I hope my body lasts. I’m having fun."

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