Public reporting burden tor this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2 Introductionon the Japanese NASDA Data Relay Test The second generation MR 509 1.8 kW Satellite (DRTS). This paper describes the hydrazine arcjet system has been based on the new system, and the power processing um M* 508 system, the first flight qualified (PPU) as well as thruster related changes that 1 8 kW arciet system by incorporating lessons became necessary for this application ana tod from S flight missions. The proved the maturity and flexibility of arcjet design upgrade successfully extended the systems, lifetime to a more demanding 13 years on orbit life Its qualification history and flight Since the thruster design had already exoerience have been described by Smith et demonstrated adequate lifetime and al^ Consequently, the MR 510 2.2 kW performance for the DRTS mission, a new hydrazine arcjet has been developed from the complete qualification of the *mier MR 509 system. The increase in power and components was not necessary. A limited incorporation of new technology enabled the delta-qualification effort was required to show arcjet to operate at higher performance. For compliance with the environmental conditions more details on the MR 510 development and during integration, launch, and on-orbii. Since qualification history see < 21 by Smith et al. the thruster integration on the satellite required 4 ' ihrusters with two different thrust levels (see The new 18kW MR 512 system was chapter "Thruster Performance"), the two developed to provide areater versatility and thrusters are now designated MR512-A and increased environmental capabilities with an -B rcspectiyely. A complete arcjet propulsion input voltage range of 31 to 51.5 VDC for use system for one satellite consists of four FPUs, »Principal Development Engineer, arcjet thrusters, member AIAA; -Senior Principal Electrical Engineer
The components of a satellite falling to the ground is a crucial problem, since titanium tanks are one of the component causing most damage to the ground in satellites. To replace titanium tanks, JAXA has researched a Melting Promotion Type Tank which can reduce residual debris during the re-entry phase. The tank structure features an aluminum liner overwrapped with carbon composite (filament winding). The demise characteristics of the new tank on re-entry were investigated in this paper. Basic evaluation for demise characteristics were conducted by analyses. In addition, two types of tests (laser heating and arc wind tunnel) were also conducted to confirm the demise characteristics of the new tank experimentally. Numerical results showed this new tank has effective demising properties. Experimental results indicate the demise mode of the new tank in re-entry condition. NomenclatureC p = specific heat capacity m = mass T = temperature T new = temperature after heat input T old = temperature before heat input T melt = temperature of melting point Q in = quantity of heat input Q out = quantity of heat release △t = time step h f = latent heat of melting r = radius of sphere λ = thermal conductivity i = suffix indicating time node j = suffix indicating space node
Molecular beam mass spectrometry was used to measure the chemical composition, angular distribution, and speed distribution in the plume of an arcjet thruster at 127 mm from the nozzle. The arcjet operating conditions were 1660 W of input power, 46.4 mg/s of simulated hydrazine propellant, and a background pressure of 0.85 mtorr. Time-of-ight spectra yielded speed distributions for N 2 , N, H 2 , and H as a function of angle µ relative to plume centerline. Absolute uxes were obtained from the experimental relative ux distributions by normalizing to the total mass ow rate. Dissociation fractions for N 2 and H 2 were 11 and 14%. Molecules near the centerline had most probable speeds of 7.4 km/s with the high end of the distribution extending to 10-12 km/s. The N 2 speed decreased to 2.7 km/s at µ = 80 deg. The N 2 and N accounted for 89% of the arcjet thrust, and the mass ux for both species decreased by a factor of 10 4 between µ = 0 and 90 deg. The angular distributions of H 2 and H were much broader, with mass uxes that decreased by less than a factor of 10 between µ = 0 and 90 deg. Other quantities derived from time-of-ight spectra were the momentum ux, kinetic power ux, average speed, and translational temperature. Nomenclature F = thrust, N f = mass ux, kg ¢ s ¡1 ¢ sr ¡1 M = molar weight, kg ¢ mol ¡1 N = number density, m ¡3 p = momentum ux, N ¢ sr ¡1 R = gas constant, 8.314510 J mol ¡1 ¢ K ¡1 r = distance from source, m S = mass spectrometer signal, V S x = detection sensitivity for species x, dimensionless T s = stream temperature, K T tr = translational temperature, K t = time, s v = velocity, m s ¡1 v s = stream velocity, m s ¡1 w = kinetic power ux, W ¢ sr ¡1 µ = polar angle relative to plume centerline, deg or rad
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