Technology: Fire delays flight of Japan's rocket

日期:2019-02-28 08:10:04 作者:璩晏 阅读:

By MICHAEL CROSS in TOKYO THE NATIONAL space agency of Japan last week revealed the latest in a series of setbacks to its flagship project, the H-II rocket. The rocket, designed as a commercial satellite launcher for the 1990s, is already running a year behind schedule. The National Space Development Agency (NASDA) said that a prototype of the main engine for the rocket had caught fire during tests at the Tanegashima Space Centre, in southern Japan, in September. The agency said that the fire, caused by a faulty computer program which failed to shut off the flow of liquid oxygen after a test firing, would set the development programme back a month. The H-II will be the first rocket designed entirely by the Japanese. Its first-stage engine is an advanced controllable motor, that burns liquid hydrogen and oxygen, like the American space shuttle. Japan’s present space workhorse, the H-I, has a first-stage engine derived from the US’s Delta rocket, a simpler design which burns kerosene and oxygen. The construction of the new engine, called the LE7, has turned out to be a daunting task. In July, NASDA had to set back the H-II’s first flight by a year, to 1993, when it found design flaws in the engine. NASDA was confident this week that this schedule would stand, despite the latest setback. Any further delays in the H-II will be highly embarrassing for NASDA, which planned the rocket to be the mainstay not only of commercial launches but also of Japan’s independent programme to send astronauts into space. It is already difficult to see how the H-II will compete in the commercial launching business: its payload to geostationary orbit will be only 2200 kilogrammes, the same as today’s proven Ariane rockets. Europe’s rocket company, Arianespace, also has the advantage of a launch site on the Equator, where the Earth’s rotation gives its maximum push. The other contenders in the business, China and the Soviet Union, subsidise their launches heavily. One advantage that Japan still has is a reputation for reliability: its rockets have yet to suffer a failure in flight. But the reputation took a knock in August, when flight controllers aborted a launch of an H-I rocket on the launch pad by shutting down the main engine after ignition. A second try at the beginning of September was a complete success, and the rocket’s cargo, the GMS-4 weather satellite,