Ion Thrusters

In my last blog post, I wrote about an idea for a more efficient method for getting things into space. I also mentioned more efficient engine design with lower throughput. That is what I will be writing about in this blog post. The type of propulsion that I will be writing about will be an ion thruster. This type of thruster is only viable in space, it does not produce much thrust, but it uses only absolutely tiny amounts of fuel. It works by ionizing xenon and repelling the ions electromagnetically at extremely high velocities.

There is one main positive quality to this type of propulsion (high-five to whoever got that joke). This is the fuel efficiency. It is more fuel efficient because of the higher speed at which the working mass is ejected. This is due to Newton's Second law which is commonly shortened to F=ma, or Force equals Mass times Acceleration. This means that in order to decrease the amount of mass required (fuel), you would need to give it more acceleration. This is achieved by the electromagnetic acceleration. While the space shuttle's main engine had a exhaust velocity of about 4.5km/s, the ion thruster would have an exhaust velocity of about 20-50km/s, making it much more efficient. An example of an achieved efficiency with this type of thruster is the Deep Space 1 spacecraft, which accelerated by 4300 m/s with only about 74 kg of xenon.

There are also two major negative qualities to this type of propulsion (same joke). One of these is the fact that it cannot be used in atmosphere. The electrical fields and electrodes require a near vacuum to function. The second is the low thrust. The thrust of current ion thrusters range from 20 to 250 milinewtons, which is tiny compared to the Space Shuttle Main Engine's 2,279 kilonewtons of force. The Space Shuttle Main Engine has about 9,116,000 to 113,950,000 times as much thrust.

Overall, in my opinion, the idea of low thrust, high efficiency engines should be explored more. In my opinion, the lower thrust is counted for in the less fuel it has to push and in the increased fuel economy. In my opinion, these types of engines could be how we power long distance ships for the future.