Ideo Masuda

Near-Field Measurement and Modeling Results for Flight-Type Arcjet: NH Molecule

Density, velocity, and temperature data were obtained in the near-e eld plume of a 1.8-kW hydrazine arcjet thruster, using the NH molecule as a probe. This was the e rst laser spectroscopic study on a e ight-type arcjet. The rotational temperature of NH was obtained in v = 0;1 of the electronic ground state and the vibrational population in v = 1;2. Rotational and vibrational temperatures were similar, and their variation along the thrust axis was minor. Line shapes as well as radial and axial proe les of the peak line intensity were obtained. Maximum laser-induced e uorescence signal was obtained on-axis 1.4 cm downstream from the exit plane, suggesting rapid NH production in the plume. Axial velocity components were determined at various plume locations. The power distribution of the available channels was found, on summation, to be in good agreement with arcjet input power. Direct simulation Monte Carlo predictions have been generated for comparison with much of the experimental data and to provide additional e owe eld information. Good agreement was achieved in most cases.

Basic Design and Fundamental Data Acquisition Test of Reentry Melting Promotion Type Satellite's Propellant Tank

Because the titanium tank is one of the greatest ground-damaging component when a low-Earth orbit satellite falls to ground, we plan to replace the general titanium propellant tank with a reentry melting promotion-type tank to reduce the ground hazard. We selected an aluminum-lined, carbon composite overwrapped tank with a lower melting temperature in a feasibility study and conducted fundamental tests including a liner material aluminum compatibility test with hydrazine propellant and an arc heating test. We also established a target specification for the tank and performed the basic design, trial manufacture, scale model PMD (Propellant Management Device) test under low gravity, CFRP outgassing property acquisition and CFRP resistance to radiation tests. This paper describes how the basic design and fundamental data acquisition test of the tank finished well. I. Introduction hen the satellite NROL-21 fell to Earth in 2008. the fall point contamination from the hydrazine propellant became problematic, while the falling rockets also caused considerable pollution. Although general tanks made from titanium alloy are used for satellite propulsion systems to save weight and ensure propellant compatibility, titanium alloy has a high melting point and is durable on reentry. However, because the titanium tank is one of the components most likely to damage the ground when a satellite in low-Earth orbit falls to ground, we plan to replace the general titanium propellant tank with one which will melt on reentry to reduce the ground hazard. We selected an aluminum-lined, carbon composite overwrapped tank with lower melting temperature in a feasibility study and conducted fundamental tests, including a liner material aluminum compatibility test with hydrazine propellant and an arc heating test. We also established a target specification for the tank, which included the mass, volume, MEOP (Maximum Expected Operating Pressure), propellant expulsion efficiency, propellant storage life, low cost, short manufacturing lead time etc. and performed the basic design, trial manufacture of key parts, scale model PMD (Propellant Management Device) test under low gravity, CFRP outgassing property acquisition test and CFRP resistance to radiation test. We set the volume 0.35m 3 at first. Because the volume was changed from 0.35m 3 to 0.43m 3 in 2013, we performed the basic design for 0.43m 3 volume.

Development of New Composite Propellant Tank for Satellites

Satellite components falling to the ground are a crucial problem, particularly titanium tanks in propulsion systems. Satellite tanks are generally made of titanium alloy because it is light and compatible with propellants used for the satellite. However, it also has a high melting point, which hinders melting on re-entry. To replace the titanium tanks, JAXA has studied as the tank for ground damage prevention on re-entry since 2010 and has started developing a new composite propellant tank since 2013. The tank is targeted; not only due to its demise properties but also its extended propellant storage, cost-effectiveness and a short delivery time. For the first development step, the minimum tank (DM: Development Model #1) which has the shortest cylindrical segment length and a volume of 250L were manufactured to confirm the strength proof of critical portions and the adequacy of production techniques. There are also plans to manufacture a PMD (Propellant Management Device) separately to the tank shell. This paper describes the design, trial productions, and data acquisition tests used when developing the new tank.

Demonstration of propellant leakage phenomena for safety assessment

Payloads launched from JAXA Launch Facilities must meet JAXA safety requirements. For one, payloads having liquid propulsion systems are required to have triple seals to prevent propellant leakage.

Basic Study of Spacecraft Plug Cluster Nozzle

We choose a plug cluster nozzle targeting use with geostationary satellites, from the perspective of installation restrictions on rockets and performance improvement. The flow properties were determined via tests and analysis using a feasibility sample scale model plug cluster nozzle, the expansion area ratio e of which was 150. We selected a plug cluster nozzle with the restriction condition and performance improvement in mind (a fusion-type plug cluster engine and cluster engine). The lack of any notable shock wave sailing across the nozzle exit plane, which would tend to cause slowdown of the exhaust gases, as seen in the module overlap region during the feasibility sample scale model test, gave us reason to believe the performance may improve when the plug cluster nozzle is used. In addition, its use was also expected to boost the base part pressure performance. No major interference between the module exhaust gases suggested no problematic heat load was likely to affect the nozzle when the combustion gases were used. Subsequently, we investigated the effect of the module overlap ratio on performance by a parameter survey on a low expansion area ratio (e25) scale model test. These nozzles showed relatively low performance due to the shock waves caused by the low expansion ratio. We attempted to estimate simply the thrust of the 8-module plug cluster nozzle using 2- or 3module cluster nozzles to reduce the cost of the study, but the estimated figures did not correlate with the thrust loss even of the low overlap ratio nozzles. We consider this attributable to the different gain zone areas, the location of the loss zone and the base pressure effect etc. This investigation will be continued by analysis and testing. Subsequently, we plan to engage in testing using the parameter survey higher expansion area ratio (e>50) scale model because the low expansion ratio nozzles have less performance by strong shock waves upstream of the nozzle exit.

FINAL OPERATION OF KAGUYA

KAGUYA (formerly SELENE) is the second Japanese lunar explorer. It was launched on Sept. 14, 2007 (JST: Japan Standard Time), and was in operation in a circular lunar orbit for approximately 21 months. Finally, we conducted maneuvered falling to