Japan, Already a Force in Space, to Build More Powerful Rocket

Japan has become a force to be reckoned with in space, launching more than two dozen unmanned rockets, some of which carried satellites to geostationary orbit.

The Japanese rockets are far smaller and have more limited payload capabilities than their European and American counterparts. Japan’s existing N-2 rocket can lift only 770 pounds to geostationary orbit 22,300 miles above the Equator. By comparison, the Ariane 4 can loft 4,400 pounds to that altitude, and the American shuttle can accommodate a satellite weighing more than 5,000 pounds.

Nonetheless, the Japanese, whose rocket technology has relied heavily on American imports, have committed themselves to developing a full-size, three-stage, all-Japanese rocket by 1991. This new rocket, the H-2, will be able to lift 4,000 pounds to geostationary orbit, meaning that the Japanese in 1991 will be where the Europeans and Americans are today.

The agreement between Japan and the United States that allows the Japanese to buy American rocket parts specifies that they may use the rockets to launch only their own satellites, not those of other nations, thus keeping the Japanese from competing with the United States for satellite launching business. The Japanese hope that by fashioning the H-2 rocket themselves, they will be able to join that competition.

Most of the Japanese satellites put into space so far are for communications and weather-forecasting purposes, though a few have taken measurements for scientific research. Earlier this year, the Japanese launched a probe to Halley’s Comet, which will rendezvous with the comet in 1986, and they plan to launch another comet probe in August.

The Europeans will also send an observer spacecraft to Halley’s Comet, as will the Soviets. Because of budget constraints, the United States scrapped its plans to explore the comet close up.