Mission to Psyche: One Year Into the Spacecraft’s Journey to a Metal-Rich Asteroid - YouTube - solar system studies

All of Psyche's instruments are working:the magnetometer;the gamma ray spectrometer;the neutron spectrometer;the imagers;and the gravity experiment.The Hall thruster engine will be the first such engine used outside the Earth/Moon system.The Hall thruster is an ion thruster engine.An ion is an atom or molecule with an electric charge due to the loss or gain of one or more electrons.Hall thrusters use a magnetic field to limit their electrons' axial motion and then use them to ionize propellant.The most common propellants used are Xenon and Krypton.Psyche could reveal some of the early history of the solar system.Some asteroids are believed to be planetesimals,chunks of material left over from the planet formation process.The definition of a planetesimal is a minute planet,a body that could or did come together with many others under gravitation to form a planet. *Credit:NASA/Jet Propulsion Laboratory-California Institute of Technology/ASU

About Ion Thruster Engines - physics

According to NASA,the most common propellant used in ion propulsion is the heavy neutral gas Xenon,which is easily ionized and has a high atomic mass,thus generating a desirable level of thrust when ions are accelerated.The thrusters work by using an electrical charge to accelerate ions from Xenon fuel to a speed 7-10 times the speed of chemical engines.An ion is defined as an atom or molecule that has gained or lost one of its valence eletrons,giving it a net positive or negative electrical charge.So it is a charged entity,as opposed to a neutral one.

This Thruster can Propel a Spacecraft Almost Indefinitely - Science Channel - physics

An ion thruster engine has been chosen to propel the NASA/ESA Gateway space station in lunar orbit.