System confirmation test conducted on the rocket with a LE-7A engine – Team Established for Better Quality and Reliability
During a firing test in October 2000, the National Space Development Agency of Japan (NASDA) detected malfunctions in the LE-7A, which is loaded as the first stage in the H-IIA launch vehicle. The failures were caused by Ni foil peeling off the oxidizer turbo pump (OTP) and leaks from the pressurization line connected to the oxidizer tank. After every effort was made to investigate the causes and take preventive measures, NASDA successfully obtained data meeting the desired performance and functionality in subsequent LE-7A firing tests.
The H-IIA FT No.1 was initially scheduled for the winter of 2000. However, the planned launch was postponed to the summer of 2001 because the agency determined it necessary to take more time to ensure unquestionable success of the median flight.
For this reason, NASDA formed a joint task force consisting of manufacturers and contractors in December 19, 2000, with the goal of reconfirming the designed quality and reliability through processes including manufacturing, testing and quality assurance.
LE-7A Engine Acceptance Firing Tests Completed
Prior to the LE-7A acceptance firing tests, the task force checked items to be confirmed, deduced the problems and took necessary measures. The acceptance firing test is conducted on the actual flight hardware for the purpose of confirming its basic functionality and performance and for correcting any problems that might hinder proper operations.
The firing test was conducted on April 12 and 16, during which a continuous firing period of 50 seconds was confirmed. The third test was conducted on April 19 (120-sec duration) by simulating the flight condition of varying pressure being applied to the interface at the propellant inlet. From the obtained data, it was confirmed that the fuel turbo pump (FTP) and OTP would function nominally even under variable interface pressures.
After the April firing tests were completed, the LE-7A was checked and integrated with the first stage on May 11. Now the all-stage system test is being conducted to confirm that onboard computer and measuring instruments accommodated in the first and second stages will function properly.
The task force continues to analyze stress incurred from vibrations in order to reconfirm the margin of lifetime of the engines. In addition, the procedures for launch operations are also being reviewed.
Median Flight Just Ahead
Prior to the LE-7A firing tests, the FTP and OTP were tested to determine the characteristics of the pump section in the flight hardware. The obtained data indicated that these turbo pumps would operate properly under the actual flight conditions.
Other components, such as the fairing and solid rocket motors, have already been manufactured and tested. After the all-stage system tests are successfully completed, the first and second stages will be transported to Tanegashima Space Center where the launch operations will be progressively conducted. The debut of the H-IIA FT No.1 is expected soon.
