Spring / Summer 1999 Table
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.
Thats 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 Grants 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,
its 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.
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 Japans 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 artists
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. Hell serve as advisor
on the Space Station Freedom for one more year. "Im a
person whos curious," he says. "Im 75 years
old. I hope my body lasts. Im having fun."