In this paper, a real-time capable Nonlinear Model Predictive Controller (NMPC) is implemented for the attitude control of an upper stage launch vehicle with liquid propellant. A mass spring model is used as an analogy to simulate the disturbance generated by the sloshing propellant. For the implementation of the NMPC, an optimal control problem (OCP) is defined with finite time horizon. The ob...

Electric propulsion devices for space applications greatly reduce the propellant mass requirements on a spacecraft in comparison to chemical rockets. To date, gridded ion engines and Hall effect thrusters (HETs) rely on thermionic hollow cathodes to supply electrons for propellant ionization and ion beam neutralization. Hollow cathodes consume up to 10% of the total propellant used in low-power...

The expedient field disposal of excess gun propellants on the ground is an integral part of live-fire training in many countries. However, burning excess propellant in the field will leave significant quantities of energetic residues and heavy metals in the environment. Compounds such as dinitrotoluene and nitroglycerin and metals such as lead will leach into the soil column, eventually migrati...

MAXIFLO-125 Inhaler Each actuation delivers: Formoterol Fumarate Dihydrate IP..................6 mcg Fluticasone Propionate IP............................125 mcg Suspended in propellant HFA 134a ...............q.s. MAXIFLO-250 Inhaler Each actuation delivers: Formoterol Fumarate Dihydrate IP .................6 mcg Fluticasone Propionate IP...........................250 mcg Suspended in propella...

1 SUMMARY To reduce the frequency of electrically initiated, 20mm munition hangfires (delayed ignitions), a joint Army/NASA investigation was conducted to recommend quality evaluation improvements for acceptance of both primers and gun propellant. This effort focused only on evaluating ignition and combustion performance as potential causes of hangfires: poor electrical initiation of the primer...

With latest improvements in MEMS, combustion based Micro-Power generation devices are seen as alternatives for conventional batteries because of the high energy densities of Hydrogen and other hydrocarbon fuels. An important feature of micro-power system is to utilize the combustion of fuel or propellant in the micro-burner to produce the gas with high temperature and high pressure to drive tur...

Lift capacity is the key performance of launch vehicle, and high chemical energy bi-propellants are commonly used for modern large liquid rockets. The residual unburned propellant has a strong effect on lift efficiency, especially orbital stages. In this paper, bias control mixture ratio studied, three models, including equal-probability depletion model (EPDM), equal-mass model(EMRM) optimum mo...

In this paper, results are presented on asymmetric sloshing in partially filled circular cylinders subjected to horizontal, periodic forcing, as well as geyser formation and the subsequent axi-symmetric sloshing that is caused by a sudden change in Bond number. Asymmetric sloshing is controlled by three parameters that are the liquid depth parameter, the frequency offset (depending on forcing f...