Credit: NASA/Glenn Research Center
NASA’s Dawn spacecraft that explored asteroid Vesta and is now en route to space rock Ceres is being propelled by ion thrust.
Ion engines use electric fields instead of chemical reactions. Ion engines tend to be much less powerful, but they are so efficient, they can last for years before running out of fuel.
Ion propulsion is accomplished by creating ions (charged particles) that are accelerated electrostatically through a potential difference. As these ions are accelerated, conservation of momentum requires that the spacecraft be accelerated in the opposite direction. This provides the thrust to change the speed of the spacecraft.
NASA’s Glenn Research Center in Ohio has been developing the next generation of ion thrusters for future missions.
It’s called the NASA Evolutionary Xenon Thruster (NEXT) Project – a seven kilowatt ion thruster.
The NEXT ion thruster has been operated for over 43,000 hours. For rocket scientists this means that the thruster has processed over 770 kilograms of xenon propellant and can provide 30 million-newton-seconds of total impulse to a spacecraft using the thruster.
This demonstrated performance permits future science spacecraft to travel to varied destinations: extended tours of multiple asteroids and comets, as well as the outer planets and their moons, for example.
By Leonard David