During November, the minds at MIT shared the controlled tests of their ionic plane. At first glance, the idea seems contradictory because ion propulsion doesn't have enough power, but the engineers arrived at a design that takes flight even with the humble initial parameters of ionization. The fact that it runs on electricity and has no moving parts gives this plane two very important advantages; however, to be truly useful, some aspects must be modified. The question is: Can it?
Ion Propulsion Explained
Ion propulsion! A fabulous technology that deserves much more attention than it receives. The Deep Space 1 probe was the first under NASA's wing to use it, and it also allowed the probe Dawn (now resting in orbit around Ceres) to achieve a velocity change of more than 10 kilometers per second. The operation of this propulsion in space vehicles like Dawn is developed from the ionization of atoms of a propellant (xenon is the most popular option). The excess electrons are attracted by the walls of the ionization chamber with a positive charge, and xenon ions move toward the exit, passing through two grids (one positive and one negative) with a huge electric potential between them.
This step drastically accelerates the xenon ions, reaching an impressive 145,000 kilometers per hour. The bad news is that the generated force is very small, 0.09 newtons. The good news? The effect is cumulative, so as long as a spacecraft has enough electricity and propellant, it will not stop accelerating. In other words, ion propulsion works very well in deep space, but MIT applied it to an atmospheric flight vehicle. This ionic plane must generate energy to overcome air resistance and take flight at the same time. The video shows that MIT's design flew for just over 56 meters. It has a wingspan of 5 meters and weighs 2.56 kilograms, meaning a person could lift it off the ground with one hand.
That translates to about 4.8 meters per second and 3.2 newtons of force, well above what a traditional ion engine can do. However, MIT's plane has an advantage: it does not have to carry its own propellant, since it uses the air from the atmosphere. Its propulsion is based on a series of miniature engines. Two electrodes, a 0.2 mm positive wire made of steel and the negative wing with an aluminum layer, are responsible for ionizing nitrogen in the air, courtesy of an electric potential of 40,000 volts, obtained with a special circuit that steps up the 200 volts (on average) from the installed LiPo batteries.
Very well... then what's the problem? Actually, there are two. The first comes down to scale. Any ionic plane will need to be larger and more robust, which increases weight, followed by energy, so we're talking about more weight, and more energy, entering a vicious circle. The second is that MIT's test (and the entire project) is being seriously questioned. On one hand, the use of a catapult for takeoff is doubted (although the data shows that the plane gains energy during flight), and on the other, many comments insist that the basic designs of the ionic plane have been in the public domain for decades, and that MIT only copied/optimized them...
