Space debris rushes along at speeds of around 10 kilometers per second, so the shock of a collision would be terrific. According to experts, a crash with an object measuring just 3 millimeters in diameter would be equivalent to being hit by a bowling ball moving at 100 kilometers per hour. A satellite would be seriously damaged if it received such a blow.

Of special concern is the damage that would occur if a flying object were to collide with the international space station that is scheduled to be built jointly within the next decade by the United States, Europe, Canada, Russia, and Japan. This space station will be the largest structure ever built in space: Its main structure alone will be the size of a small apartment building, and personnel will be permanently stationed on it. The participating countries and experts are naturally very concerned.

For this reason, plans are being made to install thin metal plates on the outside of the living quarters, which would dissipate the energy of a collision with space litter, and also to enable the space station to alter its course if a crash appeared imminent.

Japan's Robot Technology
Japan has decided to strengthen the monitoring setup necessary to forecast potential collisions. According to a plan by the Science and Technology Agency, a dome-shaped radar facility and a large optical telescope with an aperture of 1 meter and a range three times that of an ordinary telescope will be constructed in Okayama Prefecture--considered the best site in Japan for monitoring space--at a total cost of 2 billion yen (14.3 million U.S. dollars at 140 yen to the dollar). The radar facility, scheduled to go into operation in 2004, will be able to track objects 1 meter in diameter at an altitude of about 600 kilometers; the telescope, which is scheduled to be completed in 2002, will be able to trace 50-centimeter objects in stationary orbit 36,000 kilometers above the Earth's surface. These facilities will be able to monitor and calculate orbits for not only space debris but also asteroids approaching Earth.

Obviously, efforts must also be made not to create any more garbage in space. For its next-generation rocket, the H-IIA, Japan is conducting research into recoverable tanks for oxygen and hydrogen to prevent their remaining in space after a satellite launch.

Despite such efforts, space debris is likely to keep on piling up in the future. So what is needed is the development of a "vacuum cleaner" in space. And for this, the world has expressed its hopes that Japan would contribute its leading-edge robot technology.