Purdue has created part of a new cubesat thruster which electromagnetically accelerates plasma to produce thrust. They have successfully tested the ignition system for more than 1.5 million pulses. This is a giant leap for extending the lifetime of electric propulsion systems for CubeSats.
With an on-board propulsion system, CubeSats are able to achieve orbital maneuvers, formation flying, constellation maintenance and precise attitude control. Chemical propulsion as one candidate for propelling smaller spacecraft into outer space has the advantage of large thrust but presents severe concerns due to its requirement for large propellant mass, high temperature and pressure, and a threat to the main payloads posed by the reactive propellant materials. Electric propulsion, in comparison, has very high exhaust velocity and fuel efficiency.
Depending on the mechanism of acceleration, traditional electric propulsion systems are generally divided into three categories:
2. electrostatic and
While R&D of the electric propulsion for CubeSats currently involves multiple technologies including pulsed plasma thruster (PPT), miniature Xenon ion thruster, electrospray, and vacuum arc thruster (VAT). these propulsion systems are still at their infancy and mostly remain less than 7 in the Technology Readiness Level scale used by NASA. The advanced CubeSat propulsion systems have not been validated in space.
A robust and compact ignitor that can reliably trigger the discharge in the electrical propulsion system throughout the entire operational lifetime is the goal of the Purdue University work.
Modification of a classic surface flashover by reducing the energy of the individual flashover event in order to reliably operate the same flashover assembly for a large number of triggering events has been demonstrated. This modified surface flashover is referred to as Low Energy Surface Flashover (LESF). LESF is intended to trigger the discharge in electric propulsion systems throughout the entire operational lifetime. LESF differs from the conventional surface flashover in reducing the duration of the high-current stage of the flashover to below less than 100–200 ns. This minimizes the damage to the LESF assembly and allows successful operation of the same assembly for over 1.5 million consecutive flashovers without failure. The amount of the seed plasma created in the individual LESF event was demonstrated to be sufficient to trigger a moderate current arc which models a discharge in an electric propulsion system.
SOURCES – Purdue University, Plasma Research Express
Written By Brian Wang. Nextbigfuture.com