Colloidal thrusters are electrostatic accelerators of charged liquid droplets. They were first proposed and then intensively studied from around 1960 to 1975 as an alternative to normal ion engines. Their appeal at that time rested with the large “molecular mass” of the droplets, which was known to increase the thrust density of an ion engine

1. Introduction Hall thrusters are electrostatic ion accelerators in which the grid system (which serves in classical ion engines to anchor the negative charges used to accelerate the ions) is replaced with a relatively strong magnetic field perpendicular to the flow

Prof. Manuel Martinez-Sanchez Page 2 of 11Bohm velocity: Why?

JB=Beam ion (and neutralizer electron current) JE=cathode emitted current Jc=ion current to cathode- potential surfaces JD=current through disch. power supply

These notes aim at providing order-of-magnitude results and at illuminating the mechanisms involved. Numerical precision will be sacrificed in the interest of physical clarity. We look first at the arc in a cooled constrictor, with no flow, expand the analysis

1 Introduction Electrostatic thrusters (“ion engines”) are the best developed type of electric propulsion device, dating in conception to the ‘50’s,(1) and having been demonstrated in space in 1964 on a suborbital flight of the SERT I spacecraft(2). The early history

Ionization and Conduction in a High-pressure Plasma A normal gas at T <3000K is a good electrical insulator, because there are almost no ∼ free electrons in it. For pressure

The STAR 13B incorporates the lightweight case developed for the STAR 13 with the propellant and nozzle design of the earlier TE-M-516 apogee motor. The motor case has been stretched 2.2 inches to provide for increased propellant loading. The motor has been used to adjust orbit inclination of a satellite from a Delta launch

Electrothermal Augmentation Concept Geostationary satellites are most of the time exposed to the sun, but they still are subject to eclipse periods around the two vernal points (March 21, September 21);

method was developed by Raschig. Anhydrous hydrazine is a clear, colorless, hygroscopic liquid with an odor similar to that of ammonia. Anhydrous hydrazine is a strong reducing agent and a weak chemical base. Aqueous hydrazine shows both oxidizing and reducing properties. Although potential data show hydrazine