Andrzej Jeziorski/SINGAPORE
Japan's National Space Development Agency (NASDA) is claiming that an apparent structural failure in the nozzle of a test booster for the new H-2A launcher is a minor problem.
Sixteen fragments of carbonfibre composite material broke away from the redesigned solid rocket booster (SRB-A) during recent ground tests at Tanegashima Space Centre.
NASDA has pinned its hopes on the more economical H-2A to turn its fortunes around after two failures of the H-2 launcher, which is too expensive to appeal to the international launch market. The H-2A is expected to offer commercial launches at half the cost of its predecessor.
The space agency says it does not view the SRB-A test incident as serious, because the material broke away after a 103s burn. In an operational launch, the boosters would separate after 100s. Measured pressure and temperature conditions during the test were normal.
The first operational launch of the H-2A is set for February 2001, carrying the European Space Agency's Advanced Relay and Technology Mission Satellite (ARTEMIS). The launcher will also carry a re-entry test vehicle developed by the Japanese Government's Institute of Space and Astronautical Science (ISAS).
NASDA investigations into the second H-2 failure in November 1999, carried out in collaboration with the Space Activities Commission (SAC), have been completed. Investigators say the failure resulted from the premature shutdown of the first stage LE-7 engine as a result of the vibration failure of impeller vanes in the engine's fuel pump.
SAC investigators say the vibration may have been caused by bubble formation in the fuel as internal pressure changed during the vehicle's ascent. According to local press reports, one investigator says the issue was raised in 1998, but was not dealt with.
Source: Flight International