In recent years, as a rule, improvement of the reliability of liquid propellant rockets becomes an international technical problem for built-up of safe space transport systems. The high performance, liquid propellant rocket engines require high-pressured turbopumps to deliver extremely low temperature propellants of liquid oxygen (LO2, boiling point 90 K) and liquid hydrogen (LH2, boiling point...

Hall thrusters and other types of electric propulsion have become a tempting alternative to traditional chemical propulsion systems due to the high specific impulses they provide at relatively high efficiencies. Unlike conventional chemical propulsion systems, electric propulsion devices do not rely on the internal energy stored within their propellant. Instead, an external power source is used...

The development of gun propellants from 2010 to 2016 has been a broad endeavor. Researchers worldwide have examined every facet of energetic materials involved with gun propulsion in efforts to improve both safety and performance. They have looked at individual molecules to maximize energy content, as well as revisiting past molecules and improving upon their original properties. A great deal o...

Nitrogen rich compounds are suitable as ingredients in low smoke propellant charges. Several high-N energetic materials are presented which are based on tetrazoles. Tetrazoles are an unique class of compounds, since they combine a high nitrogen content and a high heat of formation with good thermal and kinetic stabilities due to their aromatic ring system. The reaction of 5azidotetrazole with h...

The recently investigated `asso model predictive control (MPC) is applied to the terminal phase of a spacecraft rendezvous and capture mission. The interaction between the cost function and the treatment of minimum impulse bit (MIB) is also investigated. The propellant consumption with `asso MPC for the considered scenario is noticeably less than with a conventional quadratic cost and control a...

Nitrocellulose is cellulose that titrated into an ester polymer which can be used as a major component in several types of ammunition and explosives other materials. Hemp (Boehmeria nivea) type fiber plant rich thrives Indonesia. Until now, the need for nitrocellulose Indonesia still imported, even though there lot potential exploited, one by synthesizing from hemp plant. One many uses derivati...

The Hall thruster is an electric propulsion device used for multiple in-space applications including orbit raising, on-orbit maneuvers, and de-orbit functions. These in-space propulsion functions are currently performed by toxic hydrazine monopropellant or hydrazine derivative/nitrogen tetroxide bi-propellant thrusters. The Hall thruster operates nominally in the 1500 s specific impulse regime....

We introduce a decentralized attitude control strategy that can dramatically reduce the usage of propellant, by taking full advantage of the physical coupling of the tether. Motivated by a controllability analysis, indicating that both array resizing and spin-up are fully controllable by the reaction wheels and the tethermotor, we report the first propellant-free underactuated control results f...

Simulations of the erosion processes for two proposed sets of ion thruster grids for the NEXT project are presented. Structural failure and electron backstreaming due to accel grid erosion are discussed as two possible failure mechanisms of these grid sets. The TAG grid set is shown to outperform the NSTAR grid set both in terms of margin against electron backstreaming and accel grid mass loss ...