Yukio Fukushima

DEVELOPMENT STATUS OF LE-7A AND LE-5B ENGINES FOR H-IIA FAMILY

Abstract On February 4th 1994, the maiden flight of H-II rocket was successfully conducted. With the completion of H-II development work, Japan has eventually got a world level spacecraft launching capability and both 1000 and 100 kN thrust class LOX/LH2 engines, LE-7 and LE-5A. H-II will be a work-horse rocket for Japans near-term future space activities. A number of studies for improving vehicle launching capability and further cost reduction are under considerations, with regard to Upgraded H-II rocket; H-IIA rocket which will be launched on 1st February 2000. The LE-7A and LE-5B are key components of the H-IIA propulsion system and also the main subject of study in these improvement plans. This paper overviews the current status of LE-7A and LE-5B according to the H-IIA configurations.

Swept Frequency Type of Ultrasonic Inspection Method for Liner-Propellant Separations of the H-I Upper-Stage Motors

This paper describes the swept frequency type of ultrasonic inspection method that is usable for inspecting not only case-liner separations, but liner-propellant separations of solid motors and successful application of the method to the H-I upper-stage motors. Unfortunately, over the past quarter of a century, the liner-propellant separations have never been inspected practically with usual ultrasonic inspection methods. The new method has been developed at the National Aerospace Laboratory (NAL) since 1968, and the inspection technique is based on the one-dimensional quarter-wavelength resonance principle for the liner thickness under one free and the other fixed end-face boundary condition, which is considered the liner-propellant separation boundary condition of the liner. Since the motor cases have curved (spherical or cylindrical) surfaces, some curved contact surface probes were developed. This method was successfully applied to the apogee and third motor of the H-I rocket at the manufactory and then at the launching site. This inspection has contributed to the successful launchings of the H-I rocket since the first launching in August 1987.

Development status of LE-7A engine

On February 4th 1994, the maiden flight of fill rocket was successfully conducted. With the completion of H-II development work, Japan has eventually got a world level spacecraft launching capability and both 100 KN and 1,000 KN thrust class LOX/LH2 engines, LE-7 and LE-5A. H-II will be a work -horse rocket for Japans near term future space activities. A number of studies for improving vehicle launching capability and further cost reduction are under considerations, with regard to Upgraded H-II rocket and Improved H-II rocket for HOPEX(HOPE experimental plane which will be launched on top of H-II). The LE-7A is a key component of the Upgraded H-II propulsion system and also the main subject of study in these improvement plans. And hot fixing test of LE-7A has been conducted since the beginning of 1997. This paper overviews the current status of LE7A according to the Upgraded H-II and Improved H-II configurations.

Low-Cycle Fatigue Test and High-Strain Fatigue Test of INCONEL718 Welded Joint in the LE-7 Rocket Engine Main Injector.

The LE-7 rocket engine main injector has undergone a few occurrences of welded joint structural failure because it is subjected to high thermal stress during the engine start and stop sequence. The low-cycle fatigue test and high-strain fatigue test which were conducted as part of failure analysis revealed that the welded joint has a considerably shorter fatigue life than expected. To improve the ductility and toughness of the welded joint, high-temperature-solution heat treatment was applied after welding. The low-cycle fatigue life of a welded joint subjected to this solution heat treatment became three times longer than that without it. A design criterion was established for low-cycle fatigue life estimation, and the life requirement was found to be satisfied.

Improved LE-7 engine - Current status (for Japanese H-II rocket)

The H-ll Rocket has been developed by National Space Development Agency of Japan(NASDA). to meet demands of heavy lift launchers for various applications in 1990s. The maiden flight of H-ll Rocket was conducted on February 4th,1994 successfully. H-ll Rocket should be work-horse rockets for Japans near term future space activities. But there are some scope for the improvement of its reliability and cost. Several studies for improving further cost reduction and enhancing launching capability and reliability are under considerations, as upgraded H-ll Rocket and H-ll Rocket for HOPE-X (HOPE experimental plane which will be launched on top of H-11). In these configurations, LE-7 Engine is the key component of its propulsion system. Improved LE-7 Engine will be applied to near term future launch vehicles, as H-ll Rocket for HOPE-X and Upgraded H-11. Improved LE-7 Engine, as new Japanese expendable booster engine, is starting to develop. This paper presents the current status and future improvement plan for Improved LE-7 engine. J

SWEPT FREQUENCY ULTRASONIC INSPECTION METHOD FOR LINER-PROPELLANT SEPARATIONS OF SOLID ROCKET MOTORS

Abstract This paper describes the swept frequency type of ultrasonic inspection method that is usable for inspecting liner-propellant separations of solid rocket motors and successful application of the method to the H-I upper-stage motors. Unfortunately, over the past quarter of a century, the liner-propellant separations have never been inspected practically with usual ultrasonic inspection methods. The special method has been developed at the National Aerospace Laboratory (NAL) since 1968, and the inspection technique is based on the one-dimensional quarter-wavelength resonance principle for the liner thickness under one free and the other fixed end-face boundary condition, which is considered the linear-propellant separation boundary condition of the linear. Since the motor cases have curved (spherical or cylindrical) surfaces, some curved contact surface probes were developed. This method was successfully applied to the apogee and third stage motor of the H-I rocket at the manufacturer and then at th...

In-flight external and internal noise measurement for TR-I rocket nose fairing

A total of three TR-I test rockets, about one-quarter size of the Japanese H-U launch vehicle, were launched in 1988 and in 1989. External and internal acoustic environments as well as vibration response of the nose fairing were measured during the ascent of each rocket. It is found that the external sound or fluctuating pressure level of the fairing is high both at lift-off and at transonic flight. However, with regard to the internal sound pressure level and the acceleration level of the fairing structure, they are high at lift-off but relatively low at transonic flight. The noise reduction (NR) and the vibration response of the structure for the rocket exhaust noise at liftoff are similar to those measured by acoustic tests in a reverberation chamber.

Neutron Radiography Using Ultra-Compact Cyclotron

Neutron radiography test was performed with ultracompact cyclotron named “BABY CYCLOTRON” which produces 16MeV proton. 9Be(p,n)9B reaction was applied for neutron soruce. The collimation system has two collimators arranged horizontally, each having cross section 14in. × 17in., L/D ratio : 52, and thermal neutron flux of 3 × 105n/cm2·s was applied at the object. Radiographic image qualities measured with ASTM indicator have shown very useful results and JSW carried out inspection of exprosive devices for NASDA.

Neutron Radiography Facility for Explosive Devices of H Launch Vehicles and its Application

In order to perform the inspection explosive devices of H-I launch vehicles by neutron radiography, we employed Baby Cyclotron as a neutron generator for NRT. As a result of performance test utilizing moderator and a collimetor, approximate 3 × 105 n/cm2 sec thermal neutron flux were obtained on the film surface. The film size of radiograph should be 14″ × 17″ and a fine and clear image quality for the inspection of explosive devices was obtained. Furthermore, this apparatus is designed to emit neutron beam in dual directions, and it has increased radiographing efficiency.