ancient times, man has imagined an unknown world when looking
up at the starlit sky. As observational technologies developed,
however, space went from being an imagined world to a scientific
one, as well as a source of discoveries and new ideas.
universe has also provided a reason for Prof. Sawaoka to become
enthusiastic about researching diamonds when he was studying
the synthesizing of substances by using shock pressure. Hexagonally
structured diamonds made from graphite under high pressure
generated by a meteorite impact were found in a meteor crater.
He had another inspiration from space, specifically Jupiter,
the huge planet made of hydrogen and helium gases. Theoretical
physics predicts that hydrogen is in the metallic state at
the core of the planet under several tens of millions of atmospheric
pressure. All substances including diamonds can be metallized
under such high pressure, according to calculations based
on theoretical physics. If it is realized, novel properties
may be discovered.
Sawaoka says, "When it was said in 1969 that one would
win a Nobel Prize if one could create metal diamonds, I decided
to make the idea come true." His goal was to create metal
diamonds by using shock pressure. All he succeeded in doing
in his laboratory, however, was to create very small diamond
particles with 50 to 100 nm in diameter. He said, "I
didn't think these small diamonds could be used in actual
applications." He tried to use them as industrial materials
by consolidating them. Ordinary diamonds are very hard but
tend to cleave when force is applied to them in a certain
direction. But carbonade, a type of natural diamond mined
mainly in Brazil, is a tough aggregate composed of very small
diamond crystals and thus it is more suitable for machine
tools. He came up with the idea of consolidating powdered
diamonds with shock pressure to produce golf ball-sized diamond
aggregates. He expected that these could be used as rock drills
for digging oil wells and tunnels. But this was not an easy
task. Diamond powder cannot be consolidated easily and becomes
graphite again with increasing its temperature to consolidate.
His attempt failed although he tried various methods including
changing temperature, pressure, shock pressure and other conditions.
Whenever he tried to enlarge the aggregates to a certain size,
his research on synthesizing diamonds with shock pressure
led to the production of fine diamond powder called "SCM
Diamond," made from graphite. He succeeded in producing
diamond powder by using only 30 to 50 kg of explosives, compared
with 1,000 to 2,000 kg of explosives used in other methods.
In his method, the volume of explosive used can be reduced
by maintaining high pressure longer through reflecting shock
waves of the explosion. In 2000, half of all diamonds produced
globally with shock pressure were synthesized using his method.
Sawaoka has been involved in experimental projects of the
National Space Development Agency of Japan (now the Japan
Aerospace Exploration Agency) since 1979. He is now the leader
of the agency's applied research project being conducted in
the International Space Station. He says, "Space development
is a history of failures and delays. It has never moved forward
as planned. The development involves long-term efforts by
people involved in it, who come and go.
A senior person who has been participating in space development
for many years and who has much knowledge about the history
of this development is needed." He has also been saying
openly that he will become an astronaut. He says, "I
want to be rewarded for working behind the scenes for many
years. My goal is not just a dream; it will come true."
It may not be long before we will see the Japan's oldest astronaut
travel to space.
(Interviewer: Yu Tatsukawa, Cosmopia Inc.)